Journal articles on the topic 'Temperature log'
To see the other types of publications on this topic, follow the link: Temperature log.
Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles
Consult the top 50 journal articles for your research on the topic 'Temperature log.'
Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.
You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.
Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.
1
Kohout, Jan, and Stanislav Vĕchet. "Low-Temperature and High-Temperature Anomalies in Temperature Shift of Stress-Lifetime Fatigue Curves." Materials Science Forum 567-568 (December 2007): 113–16. http://dx.doi.org/10.4028/www.scientific.net/msf.567-568.113.
Full textAbstract:
Most families of S-N curves determined at various temperatures present certain general regularities on whose basis the Basquin equation describing finite-life S-N curves can be generalized for various temperatures. This equation can be represented by straight lines with common slope if log-log fit for stress vs. temperature dependence is used. Deviations from these straight lines (anomalies) are evidence that additional degradation mechanisms are effective besides fatigue, whose temperature dependences differ from the mentioned temperature dependence of fatigue strength. In high-temperature region it is most often cyclic creep, in low-temperature region athermal processes of plastic deformation can play significant role in fatigue failure.
2
Longmore, A. J., R. Dixon, I. Skillen, R. F. Jameson, and J. A. Fernley. "RR Lyrae Stars and the Sandage Period-Shift Effect Examined Using IR-Derived Temperatures." International Astronomical Union Colloquium 111 (1989): 274. http://dx.doi.org/10.1017/s0252921100011829.
Full textAbstract:
AbstractMean temperatures for RR Lyrae stars in 7 globular clusters (M3, M4, M5, M15, M107, ω Cen and NGC 5466) have been determined using the optical-infrared colour <V>-<K> as a temperature indicator. Where <K> has been relatively well determined, from means of 3 or more observations, the scatter in relationships such as Log P’ vs log (temperature) and log (temperature) vs (blue amplitude) is significantly reduced when IR-derived temperatures are used instead of those derived from (B-V). Within the observational errors, the gradient in the log P’ vs log (temperature) diagram is the same for each cluster. Temperatures derived from <V>-<K> should also be less sensitive to metallicity differences than their optically derived counterparts. The Sandage Period-Shift Effect has therefore been re-examined using 6 of the 7 clusters (NGC 5466 was excluded because of too few data). A strong correlation between period-shift and metallicity is found; a smaller shift (but in the same sense) is also found for the temperature – amplitude relationship.
3
INGHAM, STEVEN C., BARBARA H. INGHAM, DARAND BORNEMAN, EMILIE JAUSSAUD, ERICA L. SCHOELLER, NATHAN HOFTIEZER, LAUREN SCHWARTZBURG, GREG M. BURNHAM, and JOHN P. NORBACK. "Predicting Pathogen Growth during Short-Term Temperature Abuse of Raw Sausage." Journal of Food Protection 72, no. 1 (January 1, 2009): 75–84. http://dx.doi.org/10.4315/0362-028x-72.1.75.
Full textAbstract:
Lag-phase duration (LPD) and growth rate (GR) values were calculated from experimental data obtained using a previously described protocol (S. C. Ingham, M. A. Fanslau, G. M. Burnham, B. H. Ingham, J. P. Norback, and D. W. Schaffner, J. Food Prot. 70:1445–1456, 2007). These values were used to develop an interval accumulation-based tool designated THERM (temperature history evaluation for raw meats) for predicting growth or no growth of Salmonella serovars, Escherichia coli O157:H7, and Staphylococcus aureus in temperature-abused raw sausage. Data (time-temperature and pathogen log CFU per gram) were obtained from six inoculation experiments with Salmonella, E. coli O157:H7, and S. aureus in three raw pork sausage products stored under different temperature abuse conditions. The time-temperature history from each experiment was entered into THERM to predict pathogen growth. Predicted and experimental results were described as growth (>0.3 log increase in CFU) or no growth (≤0.3 log increase in CFU) and compared. The THERM tool accurately predicted growth or no growth for all 18 pathogen-experiment combinations. When compared with the observed changes in log CFU values for the nine pathogen-experiment combinations in which pathogens grew, the predicted changes in log CFU values were within 0.3 log CFU for three combinations, exceeded observed values by 0.4 to 1.5 log CFU in four combinations, and were 1.2 to 1.4 log CFU lower in two combinations. The THERM tool approach appears to be useful for predicting pathogen growth versus no growth in raw sausage during temperature abuse, although further development and testing are warranted.
4
Douaa, Alsaeed, and Deri Fawaz. "Rheological and Prediction of melt viscosity flow curves for blend of Polycarbonate (PC) and Polyacrylonitrile butadiene styrene (ABS)." International Journal of ChemTech Research 12, no. 6 (2019): 33–40. http://dx.doi.org/10.20902/jctr.2019.120605.
Full textAbstract:
A knowledge of the variation of melt viscosity of thermoplastic polymers with both shear rate and temperature is of considerable importance to plastics engineers as well as to polymer rheologists. The Actual measurement of melt viscosity at large number of temperatures and shear rates is frequently a tedious and time-consuming task. The experimental validity for superimposing Log shear stress – Log shear rate curves at different temperatures along the log shear rate axis has been established for the mixture of (polycarbonate and polyacrylonitrile butadiene styrene). The temperature dependence of the resultant shift factors has been determined to predict viscosities as a function of temperature and shear rate is discussed
5
PAN, HAO, MATTHEW BUENCONSEJO, KARL F. REINEKE, and Y. CAROL SHIEH. "Effect of Process Temperature on Virus Inactivation during High Hydrostatic Pressure Processing of Contaminated Fruit Puree and Juice." Journal of Food Protection 79, no. 9 (September 1, 2016): 1517–26. http://dx.doi.org/10.4315/0362-028x.jfp-16-004.
Full textAbstract:
ABSTRACT High pressure processing (HPP) can inactivate pathogens and retain fruit qualities. Elevated HPP pressure or time increases virus inactivation, but the effect of temperature is not consistently observed for norovirus and hepatitis A virus. In the present study, the effectiveness of HPP holding temperatures (<40°C) and pressures were evaluated for inactivating surrogates (murine norovirus [MNV] and MS2 coliphage) in pomegranate and strawberry juices and strawberry puree using a 24-liter HPP system. The holding temperature was established by setting the HPP initial temperature via pretrials. All trials were able to arrive at the designated holding pressure and holding temperature simultaneously. MNV inactivation in juices was conducted at 300 MPa for 3 min with various holding temperatures (10 to 30°C). A regression equation was derived, Y = −0.08 × X + 2.6 log PFU, R2 = 0.96, where Y is the log reduction and X is the holding temperature. The equation was used to predict a 2.6-log reduction in juices at 0°C holding temperature and indicated that MNV inactivation was inversely proportional to temperature increase. MNV survival during HPP did not differ significantly in pomegranate and strawberry juices. However, MS2 coliphage inactivation was greater as the holding temperature increased (from 15 to 38°C) at 600 MPa for 3 min. The increased inactivation trend is presumably similar to that for hepatitis A virus, but the holding temperature was not correlated with the reduction of HPP-resistant MS2 in strawberry puree. When the HPP holding pressure was evaluated independently in strawberry puree, a 5-log reduction of MNV was predicted through regression analysis at the holding pressure of 424 MPa for 3 min at 20°C. These parameters should inactivate >5 log PFU of MNV in juices, based upon a greater inactivation in berry juice than in puree (1.16-versus 0.74-log reduction at 300 MPa). This research illustrates use of predictive inactivation and a feasible means for manipulating HPP parameters for effective virus inactivation in fruit juices and puree.
6
Tirta, Gabriella Devina, Leon Martin, Mario Donald Bani, Katherine Kho, Ihsan Tria Pramanda, Liew Phing Pui, Yu Hsuan How, Crystale Siew Ying Lim, and Putu Virgina Partha Devanthi. "Spray Drying Encapsulation of Pediococcus acidilactici at Different Inlet Air Temperatures and Wall Material Ratios." Foods 12, no. 1 (December 28, 2022): 165. http://dx.doi.org/10.3390/foods12010165.
Full textAbstract:
Pediococcus acidilactici has gained research and commercial interest due to its outstanding probiotic properties, yet its survival during storage and consumption requires improvement. This study aims to enhance P. acidilactici survival using spray drying encapsulation. Different inlet air temperatures (120 °C, 150 °C, and 170 °C) and whey protein isolate (WPI):gum arabic (GA) ratios (1:1, 3:1, 1:3) were tested. Cell viability was significantly (p < 0.05) affected by the inlet temperature but not the WPI:GA ratio. Increasing the inlet temperature to 170 °C significantly decreased P. acidilactici viability by 1.36 log cycles, from 8.61 log CFU/g to 7.25 log CFU/g. The inlet temperature of 150 °C resulted in a powder yield (63.12%) higher than at 120 °C (58.97%), as well as significantly (p < 0.05) lower moisture content (5.71%) and water activity (aw 0.21). Viable cell counts in all encapsulated P. acidilactici were maintained at 5.24–6.75 log CFU/g after gastrointestinal tract (GIT) simulation, with WPI:GA of 3:1 and inlet temperature 150 °C having the smallest log reduction (0.3 log cycles). All samples containing different WPI:GA ratios maintained sufficient viability (>7 log CFU/g) during the first three weeks of storage at 25 °C. These results could provide insights for further developing P. acidilactici as commercial probiotic products.
7
Brzic, Sasa, Ljiljana Jelisavac, Jela Galovic, Danica Simic, and Jelena Petkovic. "Viscoelastic properties of hydroxyl-terminated poly(butadiene) based composite rocket propellants." Chemical Industry 68, no. 4 (2014): 435–43. http://dx.doi.org/10.2298/hemind130426067b.
Full textAbstract:
In the present study, the viscoelastic response of three composite solid propellants based on hydroxyl-terminated poly(butadiene), ammonium perchlorate and aluminum has been investigated. The investigation was surveyed by dynamic mechanical analysis over a wide range of temperatures and frequencies. The mechanical properties of these materials are related to the macromolecular structure of the binder as well as to the content and nature of solid fillers. The storage modulus, loss modulus, loss factor and glass transition temperature for each propellant sample have been evaluated. The master curves of storage (log G' vs log ?) and loss modulus (log G'' vs log ?) were generated for each propellant. A comparison of logaT vs temperature curves for all propellants indicate conformance to Williams-Landel-Ferry equation. Choosing the glass transition as the reference temperature, WLF equation constants are determined. Fractional free volume at the glass transition temperature and thermal coefficient of free volume expansion values are in accordance with the consideration that Al is reinforcing filler.
8
MURPHY, R. Y., K. H. DRISCOLL, L. K. DUNCAN, T. OSAILI, and J. A. MARCY. "Thermal Lethality of Salmonella in Chicken Leg Quarters Processed via an Air/Steam Impingement Oven." Journal of Food Protection 67, no. 3 (March 1, 2004): 493–98. http://dx.doi.org/10.4315/0362-028x-67.3.493.
Full textAbstract:
Chicken leg quarters were injected with 0.1 ml of the cocktail culture per cm2 of the product surface area to contain about 7 log(CFU/g) of Salmonella. The inoculated leg quarters were processed in an air/steam impingement oven at an air temperature of 232°C, an air velocity of 1.4 m/s, and a relative humidity of 43%. The endpoint product temperatures were correlated with the cooking times. A model was developed for pathogen thermal lethality up to 7 log(CFU/g) reductions of Salmonella in correlation to the product mass (140 to 540 g) and cooking time (5 to 35 min). The results from this study are useful for validating thermal lethality of pathogens in poultry products that are cooked via impingement ovens.
9
Nummert, Vilve, and Mare Piirsalu. "Separation of ortho Inductive, Resonance and Steric Terms in Alkaline Hydrolysis of Substituted Phenyl Benzoates and Phenyl Tosylates." Collection of Czechoslovak Chemical Communications 67, no. 12 (2002): 1833–57. http://dx.doi.org/10.1135/cccc20021833.
Full textAbstract:
The second-order rate constants k2 (l mol-1 s-1) for the alkaline hydrolysis of meta-, para- and ortho-substituted phenyl benzoates C6H5CO2C6H4-X and phenyl tosylates 4-CH3-C6H4SO2OC6H4-X in aqueous 5.3 M NaClO4 have been measured spectrophotometrically at various temperatures. The log k values at a single temperature were analysed according to the equations log km,p = log k0 + (ρ)°m,pσ°, log kortho = log k0+ (ρI)orthoσI + (ρR)orthoσR° + δorthoυ and log km,p,ortho = log k0+ (ρI)orthoσI + (ρI)metaσI + (ρI)paraσI + (ρR)orthoσR° + (ρR)metaσR° + (ρR)paraσR° + δorthoυ. In the case of various temperatures, the equation for data processing involved the additional c1(1/T) term and the cross term cm,p(1/T)σ° or c2(1/T)σI and c3(1/T)σR° different for ortho-, meta- and para-substituted derivatives. As the measure of the steric influence from ortho position, the Charton υ values were used. In the case of a single temperature, the sensitivity to the inductive effect of ortho substituents was found to be about 1.7 times (in water 1.5 times) stronger than that of para and meta substituents in both reaction series studied. The variation of the ortho inductive influence with temperature appeared to be more than twice larger than that for para substituents. Compared to water, in aqueous 5.3 M NaClO4 the inductive effect from ortho position was nearly unchanged while the para inductive effect was found to be about 0.13 units of ρI smaller in the case of both reaction series studied, though the polar effects in these reaction series differ about two-fold. Due to different variation of the ortho and para inductive effects with solvent and temperature, the relative increase in the ortho effect was observed when going from water to aqueous 5.3 M NaClO4.
10
WARD, MICHELLE, RADHIKA DHINGRA, JUSTIN V. REMAIS, HOWARD H. CHANG, LYNETTE M. JOHNSTON, LEE-ANN JAYKUS, and JUAN LEON. "Associations between Weather and Microbial Load on Fresh Produce Prior to Harvest." Journal of Food Protection 78, no. 4 (April 1, 2015): 849–54. http://dx.doi.org/10.4315/0362-028x.jfp-14-381.
Full textAbstract:
Contaminated produce causes approximately 1 million cases of foodborne illness and 1 billion dollars in damages to the U.S. economy annually. The environmental conditions, especially weather, that influence the inoculation, proliferation, and dispersal of microbial load on produce are not well understood. Using a mixed models approach, we examined the relationship of temperature and precipitation to microbial indicators of contamination on fresh produce on the farm over a week-long period prior to harvest. Between 2000 and 2002, we assayed for four microbial indicators of contamination (aerobic plate count, Enterococcus, total coliforms, and Escherichia coli) on 10 produce types in 15 fields in the southern United States. The sample collection times varied, with most occurring between January and May. We collected hourly weather data for the corresponding time period and location. Our results indicated that there was a significant association between the average daily temperature (20°C) and both log aerobic plate count (e.g., an increase of 0.074 log CFU/g [standard error {SE}, 0.023] per °C increase in weekly average temperature) and log Enterococcus (e.g., an increase of 0.15 log CFU/g [SE, 0.031] per °C increase in weekly average temperature) for approximately 5 days prior to sample collection. Daily total precipitation was significantly associated with log coliforms on 2 days (~0.11 log CFU/g [SE, 0.06] per mm of precipitation) during the week-long lag period prior to harvest. Our results suggest that microbial indicator concentrations may increase as the temperature increases. Precipitation may have a positive but complex relationship with microbial indicators, as precipitation may create moist conditions conducive to bacterial growth, spread contamination onto the field, or wash contamination off of the plant.
11
Acharya, Y. B., and S. G. Tikekar. "Low‐current temperature compensated bipolar log‐ratio amplifier." Review of Scientific Instruments 64, no. 6 (June 1993): 1652–54. http://dx.doi.org/10.1063/1.1144042.
Full text
12
Ucok Alakavuk, Didem, Safak Ulusoy, Serap Cosansu, and Sühendan Mol. "Reduction of Salmonella Enteritidis in Fish by Microwave Cooking." Turkish Journal of Fisheries and Aquatic Sciences 21, no. 11 (July 12, 2021): 535–40. http://dx.doi.org/10.4194/1303-2712-v21_11_01.
Full textAbstract:
The effect of microwave cooking on the survival of Salmonella Enteritidis was investigated. Inoculated whiting and salmon fillets (6-7 log cfu/cm2) were cooked in microwave either packed or unpacked at two internal temperatures (50 and 70°C). When the samples were cooked up to the internal temperature of 50°C, the reductions were 1.82 log cfu/cm2 (29%) for packed and 0.69 log cfu/cm2 (11%) for unpacked whiting. For the same cooking temperature, the reductions were 2.39 (33%) and 0.73 log cfu/ cm2 (10%) for packed and unpacked salmon, respectively. When the internal temperature was 70°C, the reductions in S. Enteritidis counts were 2.89 (45%) and 3.90 cfu/cm2 (54%) unpacked whiting and salmon, respectively. However, the reductions were higher in packed samples of both fish cooked to 70C internal temperature than that of unpacked samples and counts of the pathogen were below the detectable level (<1.00 log cfu/cm2 ). These results suggested that packaging increased the S. Enteritidis reduction during microwave cooking and the reductions were higher in salmon than that of whiting. Microwave-cooking instructions must be included in the MW operating manuals. The foods must be cooked in microwave not lower than 360 W and 70°C.
13
MISHRA, ABHINAV, MIAO GUO, ROBERT L. BUCHANAN, DONALD W. SCHAFFNER, and ABANI K. PRADHAN. "Prediction of Escherichia coli O157:H7, Salmonella, and Listeria monocytogenes Growth in Leafy Greens without Temperature Control." Journal of Food Protection 80, no. 1 (December 21, 2016): 68–73. http://dx.doi.org/10.4315/0362-028x.jfp-16-153.
Full textAbstract:
ABSTRACT A recent study by the Centers for Disease Control and Prevention reported that between 1998 and 2008, leafy greens outbreaks accounted for 22.3% of foodborne outbreaks in the United States. Several studies on the growth of bacteria at different temperatures have been conducted; however, there is a need for the prediction of bacterial growth when leafy greens are transported without temperature control. Food products, when taken out of refrigeration, undergo a temperature change, with the rate of temperature change being proportional to the difference in the temperature of food and its surroundings. The objective of this study was to estimate the growth of Escherichia coli O157:H7, Salmonella enterica, and L. monocytogenes in leafy greens during transportation from retail to home at ambient temperatures ranging from 10 to 40°C for up to 10 h. Experiments were conducted to monitor the temperature increase in fresh spinach taken from refrigeration temperature to ambient temperature. The growth of pathogens was predicted using these changing temperature profiles with the three-phase linear model as a primary model and the square root model as the secondary model. The levels of E. coli O157:H7, S. enterica, and L. monocytogenes increased by 3.12, 2.43, and 3.42 log CFU at 40°C for the 10-h period, respectively, when no lag phase was assumed. If leafy greens are not kept out of refrigeration for more than 3 h, when the air temperature is 40°C or more, pathogen growth should be less than 1 log CFU. These results would assist in developing recommendations for food transportation without refrigeration.
14
Alm, Per-Gunnar. "The Temperature Decay Log: a different approach to presenting a temperature survey." Geological Society, London, Special Publications 65, no. 1 (1992): 339–48. http://dx.doi.org/10.1144/gsl.sp.1992.065.01.26.
Full text
15
Mančušková, Tatiana, Alžbeta Medved’ová, and Ľubomír Valík. "Viability of Lactobacillus acidophilus NCFM Howaru Dophilus during storage at refrigeration temperatures." Acta Chimica Slovaca 8, no. 1 (April 1, 2015): 17–21. http://dx.doi.org/10.1515/acs-2015-0004.
Full textAbstract:
Abstract A strain Lactobacillus acidophilus NCFM Howaru Dophilus is a probiotic bacterium available in dairy products and dietary supplements since 1970s. Its positive health effects have been proved by many studies. This work deals with the examination of NCFM strain’s viability during its storage at stable and unstable temperature in MRS broth and ultra-pasteurized milk. In nutritionally rich environment, Lb. acidophilus NCFM was able to survive and to metabolize the media. The relevant decrease of viable cells was observed in MRS broth about 30 days after inoculation, and in milk after 21 to 45 days at both stable and unstable temperatures, respectively. The average rate of decrease of viable cells was approximately two to three times higher in experiments at unstable temperature (GrMRS,unst = −0.149 log CFU.ml−1.d−1 in MRS broth, Grmilk,unst = 0.030 log CFU.ml−1.d−1 in milk) compared with that at stable temperature (GrMRS,st = −0.079 log CFU.ml−1.d−1 in MRS broth, Grmilk,st = 0.009 log CFU.ml−1.d−1 in milk). In the MRS broth exhausted by overnight cultivation of NCFM strain the decrease of viable cells started practically immediately (Grovernigh,unst = −0.137 log CFU.ml−1.d−1). Maintenance of the culture in milk at stable temperature was proved to be the most appropriate form of its storage.
16
LUBLIN, AVISHAI, ILANA MALER, SARA MECHANI, RIKY PINTO, and SHLOMO SELA-SALDINGER. "Survival of Salmonella enterica Serovar Infantis on and within Stored Table Eggs." Journal of Food Protection 78, no. 2 (February 1, 2015): 287–92. http://dx.doi.org/10.4315/0362-028x.jfp-14-066.
Full textAbstract:
Contaminated table eggs are considered a primary source of foodborne salmonellosis globally. Recently, a single clone of Salmonella enterica serovar Infantis emerged in Israel and became the predominant serovar isolated in poultry. This clone is currently the most prevalent strain in poultry and is the leading cause of salmonellosis in humans. Because little is known regarding the potential transmission of this strain from contaminated eggs to humans, the objective of this study was to evaluate the ability of Salmonella Infantis to survive on the eggshell or within the egg during cold storage or at room temperature. Salmonella cells (5.7 log CFU per egg) were inoculated on the surface of 120 intact eggs or injected into the egg yolk (3.7 log CFU per egg) of another 120 eggs. Half of the eggs were stored at 5.5 ± 0.3°C and half at room temperature (25.5 ± 0.1°C) for up to 10 weeks. At both temperatures, the number of Salmonella cells on the shell declined by 2 log up to 4 weeks and remained constant thereafter. Yolk-inoculated Salmonella counts at cold storage declined by 1 log up to 4 weeks and remained constant, while room-temperature storage supported the growth of the pathogen to a level of 8 log CFU/ml of total egg content, as early as 4 weeks postinoculation. Examination of egg content following surface inoculation revealed the presence of Salmonella in a portion of the eggs at both temperatures up to 10 weeks, suggesting that this strain can also penetrate through the shell and survive within the egg. These findings imply that Salmonella enterica serovar Infantis is capable of survival both on the exterior and interior of table eggs and even multiply inside the egg at room temperature. Our findings support the need for prompt refrigeration to prevent Salmonella multiplication during storage of eggs at room temperature.
17
Jung, Woo Young, and Tae Kwon Ha. "High Temperature Deformation Behavior of 8090 Al-Li Alloy." Advances in Materials Science and Engineering 2013 (2013): 1–9. http://dx.doi.org/10.1155/2013/512606.
Full textAbstract:
High temperature deformation behavior, especially the superplasticity of an 8090 Al-Li alloy, was studied within the recent framework of the internal variable theory of structural superplasticity. In this study, a series of load relaxation tests were conducted at various temperatures ranging from 200°C to 530°C to obtain the flow curves of log ε˙versus log ε. The effect of grain size was also examined by varying the grain sizes through a proper thermomechanical treatment. The flow curves were found to be composite curves consisting of contributions from grain boundary sliding (GBS) and grain matrix deformation (GMD) at superplastic temperatures. The activation energy obtained for GMD was 124.9 kJ/mole in the temperature range from 470°C to 530°C, very similar to that for self-diffusion in pure Al.
18
HWANG, CHENG-AN. "Effect of Salt, Smoke Compound, and Storage Temperature on the Growth of Listeria monocytogenes in Simulated Smoked Salmon†." Journal of Food Protection 70, no. 10 (October 1, 2007): 2321–28. http://dx.doi.org/10.4315/0362-028x-70.10.2321.
Full textAbstract:
Smoked salmon can be contaminated with Listeria monocytogenes. It is important to identify the factors that are capable of controlling the growth of L. monocytogenes in smoked salmon so that control measures can be developed. The objective of this study was to determine the effect of salt, a smoke compound, storage temperature, and their interactions on L. monocytogenes in simulated smoked salmon. A six-strain mixture of L. monocytogenes (102 to 103 CFU/g) was inoculated into minced, cooked salmon containing 0 to 10% NaCl and 0 to 0.4% liquid smoke (0 to 34 ppm of phenol), and the samples were stored at temperatures from 0 to 25°C. Lag-phase duration (LPD; hour), growth rate (GR; log CFU per hour), and maximum population density (MPD; log CFU per gram) of L. monocytogenes in salmon, as affected by the concentrations of salt and phenol, storage temperature, and their interactions, were analyzed. Results showed that L. monocytogenes was able to grow in salmon containing the concentrations of salt and phenol commonly found in smoked salmon at the prevailing storage temperatures. The growth of L. monocytogenes was affected significantly (P < 0.05) by salt, phenol, storage temperature, and their interactions. As expected, higher concentrations of salt or lower storage temperatures extended the LPD and reduced the GR. Higher concentrations of phenol extended the LPD of L. monocytogenes, particularly at lower storage temperatures. However, its effect on reducing the GR of L. monocytogenes was observed only at higher salt concentrations (>6%) at refrigerated and mild abuse temperatures (<10°C). The MPD, which generally reached 7 to 8 log CFU/g in salmon that supported L. monocytogenes growth, was not affected by the salt, phenol, and storage temperature. Two models were developed to describe the LPD and GR of L. monocytogenes in salmon containing 0 to 8% salt, 0 to 34 ppm of phenol, and storage temperatures of 4 to 25°C. The data and models obtained from this study would be useful for estimating the behavior of L. monocytogenes in smoked salmon.
19
SANTILLANA FARAKOS, SOFIA M., DONALD W. SCHAFFNER, and JOSEPH F. FRANK. "Predicting Survival of Salmonella in Low–Water Activity Foods: An Analysis of Literature Data." Journal of Food Protection 77, no. 9 (September 1, 2014): 1448–61. http://dx.doi.org/10.4315/0362-028x.jfp-14-013.
Full textAbstract:
Factors such as temperature, water activity (aw), substrate, culture media, serotype, and strain influence the survival of Salmonella in low-aw foods. Predictive models for Salmonella survival in low-aw foods at temperatures ranging from 21 to 80°C and water activities below 0.6 were previously developed. Literature data on survival of Salmonella in low-aw foods were analyzed in the present study to validate these predictive models and to determine global influencing factors. The results showed the Weibull model provided suitable fits to the data in 75% of the curves as compared with the log-linear model. The secondary models predicting the time required for log-decimal reduction (log δ) and shape factor (log β) values were useful in predicting the survival of Salmonella in low-aw foods. Statistical analysis indicated overall fail-safe secondary models, with 88% of the residuals in the acceptable and safe zones (<0.5 log CFU) and a 59% correlation coefficient (R2 = 0.35). A high variability in log δ-values and log β-values was observed, emphasizing the importance of experimental design. Factors of significant influence on the times required for first log-decimal reduction included temperature, aw, product, and serotype. Log β-values were significantly influenced by serotype, the type of inoculum (wet or dry), and whether the recovery media was selective or not. The results of this analysis provide a general overview of survival kinetics of Salmonella in low-aw foods and its influencing factors.
20
WEI, JIE, YAN JIN, J. THOMAS SIMS, and KALMIA E. KNIEL. "Fate of Human Enteric Viruses during Dairy Manure–Based Composting." Journal of Food Protection 73, no. 8 (August 1, 2010): 1543–47. http://dx.doi.org/10.4315/0362-028x-73.8.1543.
Full textAbstract:
Murine norovirus 1 (MNV-1), Aichi virus (AiV), and human adenovirus 41 (Ad41) were seeded in dairy manure and composted for 60 days, and both the stability of virus genomes and infectious viruses were evaluated. For compost started in late fall, pile temperature reached approximately 54.5°C on day 1 and remained between 55 and 60°C for 3 days. For viral genomes, AiV had an approximate 1.4-log loss of viral genome after 1 day and more than a 3.1-log loss after 2 days; while for MNV-1, there was a roughly 0.6-log reduction on day 1 and a more than 4-log reduction after 5 days. For compost started in late spring, the center temperature reached about 70°C on day 1 and remained warmer than 65°C for 3 days. The MNV-1 viral genome level was below the detection limit (ca. 3.4 log reverse transcriptase and quantitative PCR unit per g) after 1 day. Compared with RNA viruses, the Ad41 DNA genome was more stable in compost started in late spring; there was no reduction in DNA after 1 day, and ca. a 2.1-log loss at 5 and 7 days. For viral infectivity, the AiV infectious concentration was below the detection limit (about 2.8 log tissue culture infectious dose assay per g) after day 1 for both trials 1 and 2, and for Ad41, there was a greater than 4-log reduction of infectivity after 1 day for trial 2. Overall, temperature is a critical factor, which affects the survival of viruses in compost, and the fate of the viral genome in the generated heat is virus dependent as well. For U.S. Environmental Protection Agency Class A compost, current compost regulations require maintaining temperatures between 55 and 70°C for at least for 3 days for a static aerated-pile system. This study indicated that these temperature conditions could effectively inactivate MNV-1, AiV, and Ad41.
21
Chan, C. K. "Temperature-dependent standard deviation of log(failure time) distributions." IEEE Transactions on Reliability 40, no. 2 (June 1991): 157–60. http://dx.doi.org/10.1109/24.87118.
Full text
22
INGHAM, STEVEN C., MELODY A. FANSLAU, GREG M. BURNHAM, BARBARA H. INGHAM, JOHN P. NORBACK, and DONALD W. SCHAFFNER. "Predicting Pathogen Growth during Short-Term Temperature Abuse of Raw Pork, Beef, and Poultry Products: Use of an Isothermal-Based Predictive Tool." Journal of Food Protection 70, no. 6 (June 1, 2007): 1446–56. http://dx.doi.org/10.4315/0362-028x-70.6.1446.
Full textAbstract:
A computer-based tool (available at: www.wisc.edu/foodsafety/meatresearch) was developed for predicting pathogen growth in raw pork, beef, and poultry meat. The tool, THERM (temperature history evaluation for raw meats), predicts the growth of pathogens in pork and beef (Escherichia coli O157:H7, Salmonella serovars, and Staphylococcus aureus) and on poultry (Salmonella serovars and S. aureus) during short-term temperature abuse. The model was developed as follows: 25-g samples of raw ground pork, beef, and turkey were inoculated with a five-strain cocktail of the target pathogen(s) and held at isothermal temperatures from 10 to 43.3°C. Log CFU per sample data were obtained for each pathogen and used to determine lag-phase duration (LPD) and growth rate (GR) by DMFit software. The LPD and GR were used to develop the THERM predictive tool, into which chronological time and temperature data for raw meat processing and storage are entered. The THERM tool then predicts a Δ log CFU value for the desired pathogen-product combination. The accuracy of THERM was tested in 20 different inoculation experiments that involved multiple products (coarse-ground beef, skinless chicken breast meat, turkey scapula meat, and ground turkey) and temperature-abuse scenarios. With the time-temperature data from each experiment, THERM accurately predicted the pathogen growth and no growth (with growth defined as Δ log CFU ≥ 0.3) in 67, 85, and 95% of the experiments with E. coli O157:H7, Salmonella serovars, and S. aureus, respectively, and yielded fail-safe predictions in the remaining experiments. We conclude that THERM is a useful tool for qualitatively predicting pathogen behavior (growth and no growth) in raw meats. Potential applications include evaluating process deviations and critical limits under the HACCP (hazard analysis critical control point) system.
23
KANDHAI, M. C., M. W. REIJ, M. van SCHOTHORST, L. G. M. GORRIS, and M. H. ZWIETERING. "Inactivation Rates of Cronobacter spp. and Selected Other Bacterial Strains in Powdered Infant Formulae Stored at Different Temperatures." Journal of Food Protection 73, no. 5 (May 1, 2010): 839–48. http://dx.doi.org/10.4315/0362-028x-73.5.839.
Full textAbstract:
The aim of this study was to determine the survival of two strains of Cronobacter (Enterobacter sakazakii) and six other bacterial strains inoculated into dry powdered infant formula (PIF) stored for 22 weeks at several temperatures between 7 and 42°C. The experimental setup involved a relatively high initial concentration of bacteria, around 104 CFU/g of powder, and enumeration of survivors with a minimum detection level of 100 CFU/g. For all strains tested, it was found that the number of bacterial cells decreased faster with increasing temperature. Cronobacter spp. cells generally survived better at high temperatures (37 and 42°C) than the other bacteria, while such a difference in survival was not apparent at other temperatures. To describe the effect of temperature on survival, both the Weibull distribution model and the log-linear model were tested. At 22°C, decline rates of 0.011 and 0.008 log units per day were found for Cronobacter sakazakii ATCC 29544 and Cronobacter strain MC10, respectively. Assuming a linear relationship between log-transformed D-values and temperature, z-values estimated for C. sakazakii ATCC 29544 and Cronobacter MC10 were 13.3 and 23.5°C, respectively. Such differences found in resistance among Cronobacter spp. would be relevant to consider when establishing quantitative risk assessments on consumer risks related to PIF.
24
Zimmerling, Todd N. "The Influence of Thermal Protection on Winter Den Selection by Porcupines, Erethizon dorsatum, in Second-Growth Conifer Forests." Canadian Field-Naturalist 119, no. 2 (April 1, 2005): 159. http://dx.doi.org/10.22621/cfn.v119i2.100.
Full textAbstract:
I investigated den type selection by Porcupines (Erethizon dorsatum), in relation to the thermal cover provided by the den type, over a period of four winters. Porcupines used log dens, stump dens and rock dens in proportion to the thermal cover provided by each den type. Based on behavioural observations of Porcupines, I assumed that the lower critical temperature for porcupines in my study area was -4°C. Both stump and rock dens provided adequate thermal protection, under most ambient conditions, to allow Porcupines to maintain their body temperature, without increasing basal metabolic rate. In most cases rock and stump dens maintained den temperatures above -4°C until ambient temperatures reached -12°C or lower. In contrast log dens provided poor thermal protection, even in years of thick snowcover. When ambient temperatures dropped below -4°C, den temperatures within log dens were also recorded below -4°C. Log dens were used least often by Porcupines, whereas stump and rock dens were used most often. Despite the large number of potential dens available to Porcupines within the study area, den use was generally limited to three dens per porcupine per winter. The limited use of dens by an individual porcupine during winter may be related to the energetic cost of finding a new den or it may be related to specific selection criteria used by Porcupines.
25
Landfeld, A., M. Karpíšková R Houška, K. Kýhos, and P. Novotná. "Verification of prediction of growth of Listeria monocytogenes micro-organism in chicken meat." Czech Journal of Food Sciences 18, No. 5 (January 1, 2000): 183–86. http://dx.doi.org/10.17221/8340-cjfs.
Full textAbstract:
Raw chicken meat was comminuted and homogenised. There were measured water activity and pH (aw = 1 for temperature 25°C, pH = 5.8 for temperature 8°C). Input raw material was investigated for the presence of Listeria monocytogenes (negative) and the raw meat was inoculated by Listeria monocytogenes CCM 4699. Number of Listeria monocytogenes, total plate count and number of coliforms were determined in the range 0–7 days by bacteriological survey for the storage temperatures 4.9, 7 and 8.3°C. The increase of Listeria monocytogenes counts has been registered for temperature 4.9°C about log 1.5 CFU/g after 6 days, for temperatures 7 and 8.3°C about 2 log CFU/g (regarding to the starting counts). The prediction for listeria growth with the aid of Food MicroModel was also made. The best agreement between the experimentally analysed number of bacteria and prediction was received for the lowest incubation temperature 4.9°C.
26
Crear, B. J., and G. N. R. Forteath. "Flow-rate requirements for captive western rock lobsters (Panulirus cygnus): effects of body weight, temperature, activity, emersion, daily rhythm, feeding and oxygen tension on oxygen consumption." Marine and Freshwater Research 52, no. 5 (2001): 763. http://dx.doi.org/10.1071/mf00004.
Full textAbstract:
Oxygen consumption (Mo 2) of P. cygnus was measured in intermittent flow respirometers. A log–log relationship with body weight (W ) remained constant over the range 15–31 °C. Mo 2 was related to body weight and temperature (T) : log 10 Mo 2 =0.814log 10W +0.051 T – 2.075.I n 400 –500 g lobsters it showed a strong response to acute temperature changes (23 –19 –15 –11 and 23 –27 –31 °C): log 10 Mo 2 = 0.045 T – 2.38. Activity caused a significant (P <0.001) increase in Mo 2, with the response being modulated by temperature and body weight. Lobsters took 5–8 h to recover from exposure to handling and emersion, the duration of the recovery period being longer at higher temperatures. A nocturnal rhythm to oxygen consumption was evident. There was a large and sustained specific dynamic action, with a peak Mo 2 of 2.19 times the standard rate occurring 7 h after feeding. Mo 2 at 23 °C was independent of the oxygen tension down to a critical oxygen tension (P c) of 46.2 Torr, be low which Mo 2 varied directly with the oxygen tension. P c varied with temperature and activity state. The data allow the design of live-holding systems and practices that provide the oxygen requirements of captive P. cygnus . Extra keyword: live holding.
27
HUANG, JINGWEI, YAGUANG LUO, and XIANGWU NOU. "Growth of Salmonella enterica and Listeria monocytogenes on Fresh-Cut Cantaloupe under Different Temperature Abuse Scenarios." Journal of Food Protection 78, no. 6 (June 1, 2015): 1125–31. http://dx.doi.org/10.4315/0362-028x.jfp-14-468.
Full textAbstract:
Effective cold chain management is a critical component of food safety practice. In this study, we examined the impact of commonly encountered temperature abuse scenarios on the proliferation of Salmonella enterica and Listeria monocytogenes on fresh-cut cantaloupe. Inoculated fresh-cut cantaloupe cubes were subjected to various temperature abuse conditions, and the growth of S. enterica and L. monocytogenes was determined. During 1 week of storage, Salmonella cell counts on fresh-cut cantaloupe increased by −0.26, 1.39, and 2.23 log units at 4°C (control), 8°C, and 12°C (chronic temperature abuse), respectively, whereas that of L. monocytogenes increased by 0.75, 2.86, and 4.17 log units. Under intermittent temperature abuse conditions, where storage temperature fluctuated twice daily to room temperature for 30 min, Salmonella cell count increased by 2.18 log units, whereas that of L. monocytogenes increased by 1.86 log units. In contrast, terminal acute temperature abuses for 2 to 4 h resulted in upwards to 0.6 log unit for Salmonella, whereas the effect on L. monocytogenes was less significant compared with L. monocytogenes on cut cantaloupe stored at 4°C. Significant deterioration of produce visual quality and tissue integrity, as reflected by electrolyte leakage, was also observed under various temperature abuse conditions.
28
Sanders, T. H., and R. S. Calhoun. "Effect of Oil and Dry Roasting of Peanuts at Various Temperatures and Times on Survival of Salmonella and Enterococcus faecium." Peanut Science 41, no. 2 (July 1, 2014): 65–71. http://dx.doi.org/10.3146/ps13-16.1.
Full textAbstract:
ABSTRACT A number of outbreaks of salmonellosis since 2006 associated with the consumption of Salmonella-contaminated peanut butter have increased concerns about this food and the associated processing methods. Laboratory studies were conducted to determine the level of Salmonella reduction associated with oil and dry roasting of peanuts. After inoculation with either Salmonella or Enterococcus faecium, peanuts were dry roasted for various time durations at 5 temperatures ranging from 129–163 C and oil roasted at 120–160 C for three different time durations. At each dry roast combination of temperature and time in the study, Salmonella and E. faecium reductions were 2.7 log Colony Forming Units (CFU)/g or greater. Dry roast temperature of 154 C provided 4.6–4.7 log CFU/g reduction of Salmonella at 10 min and greater than 5.4 log CFU/g reduction at15 min. Oil roasting for 1.5 min at 150 C resulted in greater than a 6.0 log CFU/g reduction of Salmonella. E. faecium log CFU/g reductions were significantly less than Salmonella reductions in all treatments indicating a greater heat tolerance by E. faecium and documentation that it is an acceptable surrogate for Salmonella on peanuts.
29
CHEN, HAIQIANG, DALLAS G. HOOVER, and DAVID H. KINGSLEY. "Temperature and Treatment Time Influence High Hydrostatic Pressure Inactivation of Feline Calicivirus, a Norovirus Surrogate†." Journal of Food Protection 68, no. 11 (November 1, 2005): 2389–94. http://dx.doi.org/10.4315/0362-028x-68.11.2389.
Full textAbstract:
Interest in high hydrostatic pressure processing as a nonthermal pasteurization process for foods continues to increase. Feline calicivirus (FCV), a propagable virus that is genetically related to the nonpropagable human noroviruses, was used for detailed evaluation of the high pressure processing parameters necessary for virus inactivation. Pressure inactivation curves of FCV strain KCD in Dulbecco's modified Eagle medium with 10% fetal bovine serum were obtained at 200 and 250 MPa as a function of time at room temperature. Pressure inactivation curves at 200 and 250 MPa also were determined as a function of temperature ranging from −10 to 50°C at treatment times of 4 and 2 min, respectively. Tailing was observed for inactivation as a function of treatment time, indicating that the linear model was not adequate for describing these curves. The two nonlinear models, the log logistic and Weibull functions, consistently produced better fit to inactivation curves than did the linear model. The mean square errors were 0.381 for the log logistic model, 0.425 for the Weibull model, and 1.546 for the linear model. For inactivation as a function of temperature, FCV was most resistant to pressure at 20°C. Temperatures above and below 20°C significantly increased pressure inactivation of FCV. A 4-min treatment of 200 MPa at −10 and 50°C reduced the titer of FCV by 5.0 and 4.0 log units, respectively; whereas at 20°C the same treatment only reduced the titer by 0.3 log units. These novel results point to the potential for using temperatures above and particularly below room temperature to lower the pressure needed to cause the desired level of virus inactivation.
30
Y., Ummul-Izzatul, Nor-Khaizura M.A.R., F. M. Ghazali, Son R., Shafiqa-Atikah M.K., and Nur-Syifa' J. "Survival of Listeria monocytogenes in turmeric-salt marinated short mackerel (Rastrelliger brachysoma) under isothermal storage temperature." Food Research 4, S2 (April 16, 2020): 48–56. http://dx.doi.org/10.26656/fr.2017.4(s2).s06.
Full textAbstract:
Short mackerel (Rastrelliger brachysoma) is a common fish consumed in Malaysia. The high protein content of fish makes it prone to contamination with bacteria, including Listeria monocytogenes. Therefore, the objective of this study is to control the growth of L. monocytogenes by marinating short mackerel with turmeric-salt and storing at various temperatures. The short mackerel was treated with 70% of ethanol before marinating with turmeric-salt in a ratio (1:1). The short mackerel were inoculated with a concentration of 108 CFU/mL of L. monocytogenes and was stored at 0, 5, 10, 15, 20, and 25˚C for 21 days. The total microbial count and L. monocytogenes count were determined for every three days from 0 days to 21 days. The growth of L. monocytogenes in marinated mackerel was from 4.30 log CFU/g (0 days at 0 ˚C) to 5.22 log CFU/g (0 days at 25 ˚C). While the total of L. monocytogenes counts in non-marinated (control), short mackerel increased significantly based on temperature and time from 4.98 log CFU/g (0 days at 0 ˚C) to 6.22 log CFU/g (0 days at 25 ˚C). These results indicated that the growth of L. monocytogenes in the presence of turmeric-salt slowed compared with the non-marinated product, although the growth of L. monocytogenes was gradually increased throughout 21 days of storage. There was a significant difference (p<0.05) in the growth of L. monocytogenes with the storage temperature. In conclusion, the turmeric-salt marination has the potential to slow the growth of L. monocytogenes in short mackerel by approximately 0.07 log CFU/g - 2.81 log CFU/g of log reduction.
31
Lee, Heeyoung, Kyungmi Kim, Soomin Lee, and Yohan Yoon. "Kinetic behaviour ofStaphylococcus aureuson cheese as a function of water activity and temperature." Journal of Dairy Research 82, no. 1 (November 10, 2014): 64–69. http://dx.doi.org/10.1017/s0022029914000569.
Full textAbstract:
This study developed mathematical models in order to evaluate the effect ofAw(Water activity) and growth temperature onStaphylococcus aureuskinetic behaviour. TheAwlevels (0·970, 0·975, 0·983, and 0·991) of cheese were adjusted by NaCl; then,Staph. aureuswas inoculated on the cheese, followed by storage at 7–30 °C for 72–720 h. Total bacterial andStaph. aureuscell counts were enumerated on tryptic soy agar and mannitol salt agar, respectively. The Baranyi model was fitted to theStaph. aureusgrowth data in order to calculate the maximum specific growth rate (μmax; log CFU/g/h), lag phase duration (λ; h), lower asymptote (N0; log CFU/g) and upper asymptote (Nmax; log CFU/g). The effects of storage temperature andAwon the kinetic parameters (μmaxand λ) were then further analysed with the Ratkowsky-type model and a polynomial equation, respectively. The root mean square error (RMSE) and relative error (RE) were calculated in order to estimate the model performance. No significant effect ofAwonStaph. aureusgrowth was observed at 7 °C; thus, the Baranyi model was fitted to the growth data from 15, 25 and 30 °C. The μmaxvalues (0·011–0·303 log CFU/g/h) increased (P<0·05) as the storage temperature andAwincreased. In addition, λ values (2·42–63·48 h) decreased (P<0·05) as storage temperature andAwincreased; yet, the effect ofAwon λ was observed only at 15 °C. The theoretical minimum storage temperature andAwwere 10·15 °C and 0·882, respectively.RMSE(0·010–1·544) andREvalues (−0·131 to 0·187) from validation indicated that model performance was appropriate. Hence, these results suggest that the developed models in this study should be useful in describing the effect of temperature andAwon the growth kinetic behaviour ofStaph. aureusin cheese along with the exposure assessment ofStaph. aureusin cheese as well.
32
BRANDL, MARIA T., ZHONGLI PAN, STEVEN HUYNH, YI ZHU, and TARA H. MCHUGH. "Reduction of Salmonella Enteritidis Population Sizes on Almond Kernels with Infrared Heat." Journal of Food Protection 71, no. 5 (May 1, 2008): 897–902. http://dx.doi.org/10.4315/0362-028x-71.5.897.
Full textAbstract:
Catalytic infrared (IR) heating was investigated to determine its effect on Salmonella enterica serovar Enteritidis population sizes on raw almond kernels. Using a double-sided catalytic IR heating system, a radiation intensity of 5,458 W/m2 caused a fast temperature increase at the kernel surface and minimal temperature differences between the top and bottom kernel surfaces. Exposure of dry kernels to IR heat for 30, 35 and 45 s resulted in maximum kernel surface temperatures of 90, 102, and 113°C, and when followed by immediate cooling at room temperature, yielded a 0.63-, 1.03-, and 1.51-log reduction in S. enterica population sizes, respectively. The most efficacious decontamination treatment consisted of IR exposure, followed by holding of the kernels at warm temperature for 60 min, which effected a greater than 7.5-log reduction in S. enterica on the kernels. During that treatment, the kernel surface temperature rose to 109°C and gradually decreased to 80°C. Similar IR and holding treatments with lower maximum kernel surface temperatures of 104 and 100°C yielded reductions of 5.3 and 4.2 log CFU/g kernel, respectively. During these treatments, moisture loss from the kernels was minimal and did not exceed 1.06%. Macroscopic observations suggested that kernel quality was not compromised by the IR-holding combination treatment, as skin morphology, meat texture, and kernel color were indistinguishable from those of untreated kernels. Our studies indicate that IR heating technology is an effective dry pasteurization for raw almonds.
33
GILL, C. O., and C. LANDERS. "Effects of Spray-Cooling Processes on the Microbiological Conditions of Decontaminated Beef Carcasses." Journal of Food Protection 66, no. 7 (July 1, 2003): 1247–52. http://dx.doi.org/10.4315/0362-028x-66.7.1247.
Full textAbstract:
Spray processes for cooling decontaminated carcasses were examined at four beef packing plants. Temperature histories were collected from deep leg sites on 25 carcasses and from randomly selected sites on the surfaces of a further 25 carcasses selected at random from carcasses undergoing cooling at each plant. Carcass cooling rates were similar at all four plants. Proliferation values calculated from surface temperature histories indicated similar increases of ≤2 log units in the numbers of pseudomonads on carcasses at all plants and increases of <0.5 and >0.5 log units in the numbers of Escherichia coli on carcasses at plants A and B and plants C and D, respectively. The numbers of aerobes recovered from carcasses after cooling were about 1 log unit larger than the numbers recovered from carcasses before cooling at plants A, B, and C but >1.5 log units larger at plant D. These increases in numbers of aerobes were in agreement with the estimated proliferations of pseudomonads. The larger increase in the number of aerobes on carcasses at plant D may be attributable to carcasses not being pasteurized at that plant, while carcasses were pasteurized at all of the other plants. The numbers of E. coli recovered from carcasses after cooling at plants B, C, and D were also in agreement with the increases calculated from surface temperature histories. However, numbers of E. coli declined by about 1 log unit during carcass cooling at plant A. This decline may have been due to death occurring during chilling for some E. coli cells that were injured rather than killed by pasteurization with sprayed hot water at plant A, whereas pasteurization with steam at plants B and C seemingly left few injured E. coli cells. The growth of bacteria on decontaminated carcasses during spray cooling at the four plants was apparently constrained by temperature alone.
34
Widaningrum, Widaningrum, Miskiyah Miskiyah, and Juniawati Juniawati. "EFIKASI CUKA KULIT PISANG DAN AIR KELAPA SEBAGAI PENGHAMBAT Listeria monocytogenes PADA DAGING AYAM." Jurnal Penelitian Pascapanen Pertanian 12, no. 2 (January 9, 2017): 93. http://dx.doi.org/10.21082/jpasca.v12n2.2015.93-104.
Full textAbstract:
Providing natural preservatives to increase the shelf life of chicken meat is a challenge, since the microbial contaminants problem has been a concern among many actors: government, business, consumers, and health practitioners. Acetic acid (known as vinegar) has properties as an antimicrobial, due to its ability to lower the pH and causing instability in the cell membrane of pathogenic bacteria. This paper aimed to assess the manufacture of vinegar from banana peel and coconut water as potentially natural preservative, and
its application to determine the effect of microbial growth inhibition of Listeria monocytogenes in chicken meat. The study was designed using a randomized factorial design with 2 factors: 1. Types of vinegar (banana peel, coconut water, commercial acetic acid and commercial lactic acid) and 2. Storage temperature (room temperature and refrigerated temperature 5-7° C), each were repeated
three times. Chicken meat that has been treated with acid soaking then stored at room temperature and cold temperatures. The results showed that banana peel and coconut water vinegar inhibit the growth of testing bacteria L. monocytogenes in chicken meat stored at
room temperature more effective (5-6 log CFU/g) than the commercial acetic acid and commercial lactic acid (7-8 log CFU/g), for 24 hours storage. In chicken meat stored in cold temperatures, banana peel and coconut water vinegar had almost the same capabilities with commercial acetic acid (5.34 log CFU/g) on storage for 12 days. The most potential vinegar to be used in refrigerated temperature
was banana peel vinegar.
35
Jensen, Dane A., David R. Macinga, David J. Shumaker, Roberto Bellino, James W. Arbogast, and Donald W. Schaffner. "Quantifying the Effects of Water Temperature, Soap Volume, Lather Time, and Antimicrobial Soap as Variables in the Removal of Escherichia coli ATCC 11229 from Hands." Journal of Food Protection 80, no. 6 (May 15, 2017): 1022–31. http://dx.doi.org/10.4315/0362-028x.jfp-16-370.
Full textAbstract:
ABSTRACT The literature on hand washing, while extensive, often contains conflicting data, and key variables are only superficially studied or not studied at all. Some hand washing recommendations are made without scientific support, and agreement between recommendations is limited. The influence of key variables such as soap volume, lather time, water temperature, and product formulation on hand washing efficacy was investigated in the present study. Baseline conditions were 1 mL of a bland (nonantimicrobial) soap, a 5-s lather time, and 38°C (100°F) water temperature. A nonpathogenic strain of Escherichia coli (ATCC 11229) was the challenge microorganism. Twenty volunteers (10 men and 10 women) participated in the study, and each test condition had 20 replicates. An antimicrobial soap formulation (1% chloroxylenol) was not significantly more effective than the bland soap for removing E. coli under a variety of test conditions. Overall, the mean reduction was 1.94 log CFU (range, 1.83 to 2.10 log CFU) with the antimicrobial soap and 2.22 log CFU (range, 1.91 to 2.54 log CFU) with the bland soap. Overall, lather time significantly influenced efficacy in one scenario, in which a 0.5-log greater reduction was observed after 20 s with bland soap compared with the baseline wash (P = 0.020). Water temperature as high as 38°C (100°F) and as low as 15°C (60°F) did not have a significant effect on the reduction of bacteria during hand washing; however, the energy usage differed between these temperatures. No significant differences were observed in mean log reductions experienced by men and women (both 2.08 log CFU; P = 0.988). A large part of the variability in the data was associated with the behaviors of the volunteers. Understanding what behaviors and human factors most influence hand washing may help researchers find techniques to optimize the effectiveness of hand washing.
36
Mai, Nga, and Van Huynh. "Kinetics of Quality Changes ofPangasiusFillets at Stable and Dynamic Temperatures, Simulating Downstream Cold Chain Conditions." Journal of Food Quality 2017 (2017): 1–9. http://dx.doi.org/10.1155/2017/2865185.
Full textAbstract:
This study was about the quality changes ofPangasiusfillets during storage under simulated temperature conditions of downstream cold chain. Sensory, chemical, and microbiological analyses were conducted over storage time and bacterial growth was modelled. Sensory quality index (QI), at five stable (1, 4, 9, 15, and 19 ± 1°C) and three dynamic temperatures, progressed faster at higher temperatures, especially with sooner temperature abuses. Total volatile basic nitrogen remained under the acceptable limit throughout all the storage conditions. Total viable psychrotrophic counts (TVC) were around 5.68 ± 0.24 log CFU g−1at the beginning and exceeded the limit of 6 log CFU g−1after 216, 96, 36, 16, and 7 h at 1, 4, 9, 15, and 19 ± 1°C, respectively. Meanwhile,Pseudomonascounts started at 3.81 ± 0.53 log CFU g−1and reached 4.60–6.36 log CFU g−1by the time of TVC rejection. Since lower shelf lives were given by TVC rather than QI, it should be appropriate to base the product shelf life on the TVC acceptable limit. Kinetics models based on the Baranyi and Roberts and square root models, developed for TVC andPseudomonasspp., gave acceptable bacterial estimations at dynamic temperatures, with over 80% of observed counts within the acceptable simulation zone, revealing promising model applicability as a supporting tool for cold chain management. However, further improvement and validation of the models are needed.
37
KIM, JUNGHEE, KAREN A. SCHMIDT, RANDALL K. PHEBUS, and IKE J. JEON. "Time and Temperature of Stretching as Critical Control Points for Listeria monocytogenes during Production of Mozzarella Cheese†." Journal of Food Protection 61, no. 1 (January 1, 1998): 116–18. http://dx.doi.org/10.4315/0362-028x-61.1.116.
Full textAbstract:
Different heating times and temperatures commonly used during curd stretching were investigated to determine their effects on the viability of Listeria monocytogenes in mozzarella cheese. Pasteurized whole milk was inoculated with two levels of L. monocytogenes (7 and 3 log CFU/g) and coagulated with citric acid and rennet. The curd was stretched at 55, 66, and 77°C for 1, 3, and 5 min. Results indicated that the majority of L. monocytogenes cells remained in the cheese curds at both inoculum levels. Stretching at 66°C for 3 min reduced the number of L. monocytogenes by 5 log units, whereas stretching at 55°C had a minimal effect. Stretching at 77°C resulted in the complete demise of L. monocytogenes cells (from 7.6 log CFU/g to < 1.0 log CFU/g) in 1 min. If the stretching temperature partially reduced microbial counts, brining (4°C for 12 h) usually had a lethal effect on the remaining microorganisms, but was less effective than the stretching temperature. These results show that stretching curd at 66°C for 5 min or 77°C for 1 min can effectively control L. monocytogenes during the production of mozzarella cheese.
38
Young, D. G., and J. A. Danik. "Effects of Temperature on Fatigue and Fracture." Rubber Chemistry and Technology 67, no. 1 (March 1, 1994): 137–47. http://dx.doi.org/10.5254/1.3538660.
Full textAbstract:
Abstract Although fatigue tests at varied temperatures are not common due to the added burden of testing, there are times when variable temperature testing is important to ensure that rubber compounds will be suitable for the full range of use conditions. This is particularly true when materials with high Tg(>−50°C) are being considered for use in tires. Results for two high Tg rubber compounds (ECO and HS-SBR) showed fatigue crack growth (FCG) rates that were roughly 100 times those of a BIIR liner compound over the temperature range of −25 to 100°C. Additional tests with BIIR and NR showed that most crack growth results for temperatures of −25 to 100°C, and various strains, followed similar fatigue functions (dc/dn vs. T). The exception was some data for NR at 0 and −25°C which showed inhibited rates of FCG due to strain crystallization. There appears to be a window of strain rate, temperature and strain level where this effect is noticed, but these results need to be confirmed for NR and other strain crystallizable elastomers. Two fully cured NR belt skims used in truck tires showed linear results for log dc/dn vs. log T at temperatures of 70 to 100°C. However, undercured samples of one compound exhibited more temperature sensitivity of FCG results; specifically, rates of FCG increased significantly with temperature at low strain levels. This suggests the need for further evaluation of the effect of cure state on FCG over a range of test temperatures.
39
CALICIOGLU, MEHMET, NANCY G. FAITH, DENNIS R. BUEGE, and JOHN B. LUCHANSKY. "Viability of Escherichia coli O157:H7 in Fermented Semidry Low-Temperature-Cooked Beef Summer Sausage." Journal of Food Protection 60, no. 10 (October 1, 1997): 1158–62. http://dx.doi.org/10.4315/0362-028x-60.10.1158.
Full textAbstract:
The population of inoculated Escherichia coli O157:H7 was monitored during the manufacture and storage of a semidry beef summer sausage processed by fermentation and cooking at a low temperature by heating to an internal temperature of 130°F (54°C). The all-beef batter (11% fat and nonmeat ingredients) was inoculated with the commercial starter culture Pediococcus acidilactici HP (≥8.6 log CFU/g of batter) and a five-strain mixture of E. coli O157:H7 (≥7 log CFU/g) and then hand stuffed into 2.5-inch (64-mm) diameter fibrous casings. The sausages were fermented at an initial temperature of 85°F (29°C) to a final temperature of 105°F (41°C) over ca. 13 h at 80% relative humidity (RH) to pH 4.6 or pH 5.0. After fermentation to pH 4.6, the internal temperature of the chubs was raised to 130°F (54°C) instantaneous over 3.6 h at 60% RH. After fermentation to pH 5.0, the internal temperature of the chubs was raised to 130°F (54°C) over 3.6 h at 60% RH and the chubs were maintained under these conditions for 0, 30, or 60 min. he chubs were cold water showered for 15 min and then chilled at 39°F (4°C) for 6 h before being vacuum packaged and stored at 39°F (4°C) or 77°F (25°C) for 7 days. Regardless of the target pH, fermentation alone resulted in only a 1.39-log CFU/g decrease in pathogen numbers. However, fermentation to pH 4.6 and heating to an internal temperature of 130°F (54°C) instantaneous reduced counts of E. coli O157:H7 by ≥7.0 log units to below detection levels (<10 CFU/g). Pathogen numbers remained below levels detectable by direct plating, but viable E. coli O157:H7 cells were recovered by enrichment of samples during sausage storage at either refrigeration or abuse temperatures. In contrast, fermentation to pH 5.0 and heating to an internal temperature of 130°F (54°C) instantaneous resulted in a 3.2-log-unit decrease in counts of E. coli O157:H7. No appreciable reductions in pathogen numbers were observed thereafter following storage at either 39°F (4°C) or 77°F (25°C) for 7 days. Fermentation to pH 5.0 and heating to an internal temperature of 130°F (54°C) instantaneous followed by holding for 30 or 60 min resulted in about a 5- or 7-log reduction, respectively, in pathogen numbers. For chubs held for 30 min at 130°F (54°C), pathogen numbers decreased to 2.02 and <1.0 log CFU/g at 39°F (4°C) and 77°F (25°C), respectively, after 7 days; viable cells were only observed by enrichment after storage at 77°F (25°C). For chubs held for 60 min at 130°F (54°C), pathogen numbers remained below levels detectable by direct plating, but viable cells were recoverable by enrichment after 7 days at both storage temperatures. These data will be useful guidelines to manufacturers for developing processing conditions to further ensure the safety of this category of fermented sausages relative to food-borne pathogens such as serotype O157:H7 strains of E. coli.
40
Nicolau-Lapeña, Iolanda, Ingrid Aguiló-Aguayo, Marina Anguera, Inmaculada Viñas, and Maribel Abadias. "Exploring thermosonication as non-chemical disinfection technology for strawberries." European Food Research and Technology 248, no. 3 (November 27, 2021): 671–83. http://dx.doi.org/10.1007/s00217-021-03913-9.
Full textAbstract:
AbstractThe scope of this work was to study the efficacy of the combination of sonication at 35 or 130 kHz with three temperature treatments: 20, 50 and 55 ºC, on the population of artificially inoculated Listeria innocua in strawberries, and on their overall quality. Prior in vitro results showed that temperature was the main factor in decreasing L. innocua population: a maximum of 3.8 log reductions was obtained with sonication at 130 kHz and 55 ºC for 15 min Treatments combining—or not—sonication at 130 kHz with mild temperatures (50 and 55 ºC) for 5 or 10 min were able to decrease about 3 log units of artificially inoculated L. innocua in strawberries and about 2 log units of total aerobic mesophilic and yeasts and molds populations naturally occurring in strawberries. Thermosonication treatments did not exert a detrimental impact on fruit quality, except for those at the higher temperatures and times, which caused a change in color to more purplish and a little softening of the strawberries, which were proposed to be assessed for further processing other than fresh commercialization. Overall, the impact of sonication in fresh strawberries needs to be further investigated to find the adequate conditions to enhance the effects of temperature itself.
41
Azim Aijaz, Mohammad, and T. S. Ravikumar. "Design and Analysis of a Heat Exchanger Network." Material Science Research India 9, no. 1 (June 20, 2012): 85–91. http://dx.doi.org/10.13005/msri/090111.
Full textAbstract:
the hot fluid outlet temperature, cold fluid outlet temperature, heat transfer rate and effectiveness at varying hot and cold fluid inlet temperatures using, log mean temperature difference (LMTD) and effectiveness-number of transfer units (ε-NTU) method. The obtained result illustrates how heat transfer rate and effectiveness increases or decreases at varying hot and cold fluid inlet temperatures. The result obtained from both LMTD and å-NTU method gives statistically significant values. The objective of this paper is to find out the optimal temperature at which heat transfer rate and effectiveness are maximum.
42
Matsunaga, Noriyuki, Mingjie Jian, Daisuke Taniguchi, and Scarlet S. Elgueta. "Line-depth ratios as indicators of effective temperature and surface gravity." Monthly Notices of the Royal Astronomical Society 506, no. 1 (June 28, 2021): 1031–44. http://dx.doi.org/10.1093/mnras/stab1770.
Full textAbstract:
ABSTRACT The analysis of stellar spectra depends on the effective temperature (Teff) and the surface gravity (log g). However, the estimation of log g with high accuracy is challenging. A classical approach is to search for log g that satisfies the ionization balance, i.e. the abundances from neutral and ionized metallic lines being in agreement. We propose a method of using empirical relations between Teff, log g, and line-depth ratios, for which we meticulously select pairs of Fe i and Fe ii lines and pairs of Ca i and Ca ii lines. Based on YJ-band (0.97–1.32 $\mu$m) high-resolution spectra of 42 FGK stars (dwarfs to supergiants), we selected 5 Fe i–Fe ii and 4 Ca i–Ca ii line pairs together with 13 Fe i–Fe i pairs (for estimating Teff), and derived the empirical relations. Using such relations does not require complex numerical models and tools for estimating chemical abundances. The relations we present allow one to derive Teff and log g with a precision of around 50 K and 0.2 dex, respectively, but the achievable accuracy depends on the accuracy of the calibrators’ stellar parameters. It is essential to revise the calibration by observing stars with accurate stellar parameters available, e.g. stars with asteroseismic log g and stars analysed with complete stellar models taking into account the effects of non-local thermodynamic equilibrium and convection. In addition, the calibrators we used have a limited metallicity range, −0.2 < [Fe/H] < +0.2 dex, and our relations need to be tested and re-calibrated based on a calibrating data set for a wider range of metallicities.
43
Verdoya, M., P. Chiozzi, and V. Pasquale. "Thermal log analysis for recognition of ground surface temperature change and water movements." Climate of the Past 3, no. 2 (June 15, 2007): 315–24. http://dx.doi.org/10.5194/cp-3-315-2007.
Full textAbstract:
Abstract. A joint analysis of surface air temperature series recorded at meteorological stations and temperature-depth profiles logged in nearby boreholes was performed to estimate conditions existing prior to the beginning of the instrumental record in central-northern Italy. The adopted method considers conductive and advective heat transport in a layered medium and provides simultaneous estimates of the pre-observational temperatures and the Darcy velocities. The reconstruction of the ground surface temperature history using a generalised least-squares inversion method was performed for boreholes where hydrological disturbances to measured temperature logs were proved negligible. Both methods revealed generally coherent climatic changes in the whole investigated area. Climatic conditions were generally warm and comparable with the reference period 1960–1990. The absence of the Little Ice Age seems to be a generic feature of the climate in central-northern Italy. Climate change of the 19th century was generally insignificant with well-balanced periods of cold and warmth. The investigated area became significantly colder only at the end of the 19th century. Cooling culminated around 1950 when it was replaced by rapid warming. Recent warming was not inferred only for one of the investigated holes.
44
Biswas, RK, and AK Karmakar. "Factorial (25) design for the extraction of V(IV) in the V(IV)-[SO42-](H+, Na+) ? Cyanex 302-kerosene system." Bangladesh Journal of Scientific and Industrial Research 51, no. 1 (March 28, 2016): 47–54. http://dx.doi.org/10.3329/bjsir.v51i1.27057.
Full textAbstract:
The title system has been investigated from the modeling points of view. Equilibration time is 20 min and the significant extraction occurs above pH 2. Considering the constancy of the organic to aqueous phase ratio (1:1), the factors affecting the extent of extraction (value of log D or log CD) are [V(IV)], pH(eq), [Cyanex 302], [SO42-] and temperature (T). The levels of these factors chosen in experimentation are high (+) and low (-). Regression or model equation for the extraction of vanadium (IV) by Cyanex 302 is determined from 25 full factorial design. On abbreviating log[V(IV)], -log(1+4641.14x10-pH + (1.5x106)x10-2pH), log[Cyanex 302], -log(1+2.24 [SO42-]) and absolute temperatures as M, P, E, S and T, respectively, the model obtained is: log CD = 10.452-0.16M+1.0047P+2.0011E+1.0003S-2425.3729/T. From the regression model it is seen that there is no interaction effect between the factors under investigation. The model can describe the system well.Bangladesh J. Sci. Ind. Res. 51(1), 47-54, 2016
45
Elloumi, Imen, Roger E. Hernández, Claudia B. Cáceres, and Carl Blais. "Effects of temperature and moisture content of logs on size distribution of black spruce chips produced by a chipper-canter at two cutting widths." BioResources 16, no. 4 (August 11, 2021): 6684–704. http://dx.doi.org/10.15376/biores.16.4.6684-6704.
Full textAbstract:
Four matched groups of black spruce logs were processed with a chipper-canter at temperatures of 20, 0, -10, and -20 °C. Each log was transformed at two moisture contents (MC, green and air-dried) using two cutting widths (CW, 12.7 and 25.4 mm). Mean MC for each CW was assessed from a sample of the obtained chips. Knot characteristics were measured on the cant surfaces after log processing. Chip size was assessed by thickness (Domtar classifier) and width/length (Williams classifier). The results showed that the chip size was significantly affected by the CW and temperature, and in a lesser degree by the chip MC. The weighted mean chip thickness (WCT) increased with the CW. As temperature decreased below 0 °C, WCT and accepts decreased, while proportions of fines and pin chips increased. Chips obtained from green logs were thinner compared to air-dried logs when processed at the coldest temperature (minus 20 °C). The number and size of knots had an important impact on chip size, particularly on WCT. Multiple regressions were developed to predict WCT. Results showed the potential benefits of measuring log temperature and knot features to reduce chip thickness variation during fragmentation and thus improving chip size uniformity.
46
Ribeiro, Ana Cristina Pinesso, Samera Rafaela Bruzaroski, Flavia De Almeida Bergonse Pereira, Fernanda Gonzales Paião, Regina Celia Poli-Frederico, Joice Sifuentes dos Santos, and Elsa Helena Walter de Santana. "Proteolytic behavior of isolated Pseudomonas spp. from refrigerated raw milk in different concentrations and storage temperatures." Semina: Ciências Agrárias 39, no. 1 (February 16, 2018): 419. http://dx.doi.org/10.5433/1679-0359.2018v39n1p419.
Full textAbstract:
The objective of the work was to evaluate the multiplication capacity and proteolytic activity of different Pseudomonas spp. cell counts inoculated in milk and storaged under different temperature. Strains isolated from refrigerated raw milk (RRM) were confirmed at genus level by Polymerase Chain Reaction (PCR). The Pseudomonas spp. was cultured in cephalothin-sodium fusidate-cetrimide (CFC) agar-base (30?C for 48 h) until it reached 2 log and 6 log CFU mL-1. Three of eight strains confirmed as Pseudomonas spp were inoculated in sterile reconstituted whole milk powder and incubated at 2°C, 4°C, and 8°C for 96 h. Primary proteolysis indices was determined by the Kjeldahl method. When taking into account the effect of storage time in Pseudomonas spp. population, it was found that the initial population (2 log CFU mL-1) showed significant difference in growth rates only from 0 h to 24 h, keeping at the same levels along 96 h. When a higher initial population was incubated (6 log CFU mL-1), it was not observed a significant difference for times tested. Related to the effect of storage time in proteolysis index, it was not observed a significant difference in samples inoculated with 2 and 6 log CFU mL-1 Pseudomonas spp. When we analyzed the influence of storage temperature on the bacterial multiplication, there was a significant difference in the Pseudomonas spp. population only between 2°C and 8°C after 96 h of milk storage with 2 log CFU/mL of initial inoculum. If we consider the temperature effect in the primary proteolysis index, there were significant differences at the inoculum of 2 log CFU mL-1 where the primary proteolysis at 24 h was lower at 2°C than at 8ºC. Low temperatures or short storage time had no influence on Pseudomonas spp. enumeration or in the primary proteolysis index when high initial contaminations are observed. At lower Pseudomonas spp. initial population, the smaller storage time tested influenced the population control, and linked with the reduction in the storage temperature, lower proteolysis index were observed.
47
ZAPICO, PALOMA, PILAR GAYA, MANUEL NUÑEZ, and MARGARITA MEDINA. "Activity of Goats' Milk Lactoperoxidase System on Pseudomonas fluorescens and Escherichia coli at Refrigeration Temperatures." Journal of Food Protection 58, no. 10 (October 1, 1995): 1136–38. http://dx.doi.org/10.4315/0362-028x-58.10.1136.
Full textAbstract:
Bactericidal activity of the lactoperoxidase (LP) system against Pseudomonas fluorescens was observed in refrigerated raw goats' milk. Mean decreases in the levels of P. fluorescens of 1.69 log units at 4°C and 1.85 log units at 8°C were achieved during the first 24 h by LP-system activation. Inhibitory activity depended on temperature and length of incubation. P. fluorescens counts lower than the initial level were recorded in activated LP-system milk for 5 days at 4°C and 3 days at 8°C. Escherichia coli did not grow in raw goats' milk at 4°C, and the influence of LP-system activation at this temperature on E. coli counts was negligible. At 8°C, E. coli was able to grow in control milk with no apparent lag phase. In contrast, a lag phase of 2 days was observed in activated LP-system milk at 8°C, resulting in lower E. coli counts than those of control milk during the first 5 days.
48
Kutasov, I. M., and L. V. Eppelbaum. "Estimation of geothermal gradients from single temperature log-field cases." Journal of Geophysics and Engineering 6, no. 2 (March 24, 2009): 131–35. http://dx.doi.org/10.1088/1742-2132/6/2/004.
Full text
49
Verdoya, M., P. Chiozzi, and V. Pasquale. "Thermal log analysis for recognition of ground surface temperature change and water movements." Climate of the Past Discussions 3, no. 1 (January 18, 2007): 95–120. http://dx.doi.org/10.5194/cpd-3-95-2007.
Full textAbstract:
Abstract. A joint analysis of surface air temperature series recorded at meteorological stations and temperature-depth profiles logged in near-by boreholes was performed to estimate conditions existing prior to the beginning of the instrumental record in central-northern Italy. The adopted method considers conductive and advective heat transport in a horizontally layered medium and provides simultaneous estimates of the pre-observational temperatures and the Darcy velocities. The reconstruction of the ground surface temperature history using an inversion method was performed for boreholes where hydrological disturbances to measured temperature logs were proved to be negligible. Both methods revealed generally coherent climatic changes in the whole investigated area. Climatic conditions were generally warm and comparable with the reference period 1960–1990. The absence of the Little Ice Age in the middle ages seems to be a generic feature of the climate in central-northern Italy. Climate change of the 19th century was generally insignificant with well balanced periods of cold and warmth. The investigated area became significantly colder only at the end of the 19th century. Cooling culminated around 1950 when it was replaced by rapid warming. Recent warming was not inferred only for one of the investigated holes. This discrepancy can be attributed to local environmental conditions.
50
Lobacz, Adriana, and Justyna Zulewska. "Fate of Salmonella spp. in the Fresh Soft Raw Milk Cheese during Storage at Different Temperatures." Microorganisms 9, no. 5 (April 27, 2021): 938. http://dx.doi.org/10.3390/microorganisms9050938.
Full textAbstract:
The aim of this study was to determine the survival kinetics of Salmonella spp. in unripened, fresh raw milk cheese during storage at 5, 15 and 25 °C. Microbiological (coliforms and E. coli, S. thermophilus, Lactococcus sp., total microbial count and Enterobacteriaceae) and physicochemical (pH and aw) characteristics were also determined. Two primary models were used to estimate the kinetic parameters of Salmonella spp., namely Weibull and Baranyi and Roberts (no lag) models. Additionally, goodness-of-fit of the primary models was assessed by calculating the R-Square and mean square error. Salmonella spp. growth in the unripened raw milk cheese was inhibited during storage, but nevertheless bacteria survived at 5 °C for 33 days (2.5 log cfu/g) and 15 °C for 18 days (1.8 log cfu/g). A decrease in the number of Salmonella spp. populations from an initial concentration 6.6 log cfu/g to below a detection limit was observed at 25 °C after 7 days of storage of contaminated cheese samples. It was concluded that the storage temperature significantly influenced the inactivation rate of Salmonella spp. in fresh raw milk cheese and proceeded faster at 25 °C compared to remaining storage temperatures.