Littérature scientifique sur le sujet « PDO Grana Padano cheese »

The microbiota of Protected Designation of Origin (PDO) cheeses plays an essential role in defining their quality and typicity and could be applied to protect these products from counterfeiting. To study the possible role of cheese microbiota in distinguishing Grana Padano (GP) cheese from generical hard cheeses (HC), the microbial structure of 119 GP cheese samples was studied by DNA metabarcoding and DNA metafingerprinting and compared with 49 samples of generical hard cheeses taken from retail. DNA metabarcoding highlighted the presence, as dominant taxa, of Lacticaseibacillus rhamnosus, Lactobacillus helveticus, Streptococcus thermophilus, Limosilactobacillus fermentum, Lactobacillus delbrueckii, Lactobacillus spp., and Lactococcus spp. in both GP cheese and HC. Differential multivariate statistical analysis of metataxonomic and metafingerprinting data highlighted significant differences in the Shannon index, bacterial composition, and species abundance within both dominant and subdominant taxa between the two cheese groups. A supervised Neural Network (NN) classification tool, trained by metagenotypic data, was implemented, allowing to correctly classify GP cheese and HC samples. Further implementation and validation to increase the robustness and improve the predictive capacity of the NN classifier will be needed. Nonetheless, the proposed tool opens interesting perspectives in helping protection and valorization of GP and other PDO cheeses.

The natural load of lactic acid bacteria (LAB) in milk is the basis of the production of raw milk cheeses, such as Grana Padano PDO. In the last decades, improvements in livestock hygiene management resulted in bulk cow milk with less than 20,000 colony forming units (CFU) of bacterial count, unable to ensure a sufficient supply of LAB, with a negative impact on cheese quality. This study investigated the relations between farm management practices and prevalence of different groups of bacteria in cow milk. Sixty-two intensive dairy farms located in Lombardy (Italy) where involved, most of them destined as milk for the production of Grana Padano. Season had no significant effect on the content of most of the bacterial groups, except for coliforms. A strong relation among standard plate count (SPC) and other bacterial groups was evidenced. Cluster analysis showed that the most productive farms applied a complete milking routine and produced milk with the lowest value of SPC, the lowest count of the other bacteria, including LAB, but the highest LAB/SPC. The study suggests that complexity of farming practices can affect the microbial population of milk.

Trentingrana hard cheese is a geographic specification of the PDO Grana Padano. It is produced according to an internal regulation by many cooperative dairy factories in the Trentino region (northern Italy), using a semi-artisanal process (the only allowed ingredients are milk, salt, and rennet). Within the PSR project TRENTINGRANA, colorimetric and textural measurements have been collected from 317 cheese wheels, which were sampled bi-monthly from all the consortium dairies (n = 15) within the timeframe of two years, to estimate the effect on physical properties related to the season of the year and the dairy factory implant. To estimate the effect of the dairy and the time of the year, considering the internal variability of each cheese wheel, a linear mixed-effect model combined with a simultaneous component analysis (LMM-ASCA) is proposed. Results show that all the factors have a significant effect on the colorimetric and textural properties of the cheese. There are five clusters of dairies producing cheese with similar properties, three different couples of months of the year when the cheese produced is significantly different from all the others, and the effect of the geometry of the cheese wheel is reported as well.

ABSTRACTSingle-chain variable-fragment antibodies (scFvs) have considerable potential in immunological detection and localization of bacterial surface structures. In this study, synthetic phage-displayed antibody libraries were used to select scFvs against immunologically active S-layer protein ofLactobacillus helveticusMIMLh5. After three rounds of panning, five relevant phage clones were obtained, of which four were specific for the S-layer protein ofL. helveticusMIMLh5 and one was also capable of binding to the S-layer protein ofL. helveticusATCC 15009. All five anti-S-layer scFvs were expressed inEscherichia coliXL1-Blue, and their specificity profiles were characterized by Western blotting. The anti-S-layer scFv PolyH4, with the highest specificity for the S-layer protein ofL. helveticusMIMLh5, was used to detect the S-layer protein in Grana Padano protected-designation-of-origin (PDO) cheese extracts by Western blotting. These results showed promising applications of this monoclonal antibody for the detection of immunomodulatory S-layer protein in dairy (and dairy-based) foods.

The volatile concentrate obtained from Grana Padano cheese by vacuum distillation was fractionated by continuous liquid–liquid extraction into neutral and acid fractions. Both were analysed by high resolution gas chromatography (HRGC), HRGC–mass spectrometry, and HRGC–olfactometry. A total of 67 components were identified in the neutral extract (22 esters, 13 alcohols, 12 ketones, 6 aldehydes, 5 nitrogen-containing compounds, 3 lactones and 6 miscellaneous compounds) and 16 in the acid extract. Esters were the predominant constituents of the neutral fraction, whose major components were ethyl butanoate and ethyl hexanoate. HRGC–olfactometry of the neutral compounds demonstrated that 23 were odour-active: ethyl butanoate, 2-heptanol, 3-methylthiopropanal, 1-octen-3-ol, ethyl hexanoate and nonanal being the most potent odorants. n-Butanoic and n-hexanoic acids were the main volatile free fatty acids identified in the acid extract as having an important odour with a high olfactometric index. The backbone of Grana Padano cheese aroma seemed to consist of these acids and 14 potent neutral odorants imparting fruity, green, nutty and coconut notes. The concentration of volatile components responsible for the fruity and green notes was inversely proportional to the length of ripening, whereas the concentration of volatile agents with spicy, nutty and earthy notes tended to increase during maturation. In a comparison of the olfactometric profile, the Grana Padano cheese aroma was found to be more complex than an imitation Grana Padano cheese produced with similar technology but outside the area of the genuine cheese. Some of the main metabolic pathways for the biosynthesis of cheese aroma are reviewed briefly to indicate the possible origin of the compounds identified.

The aim of this study was to assess the effect of chemical composition, coagulation properties, pH, and titratable acidity (TA, SH°/50 ml) of vat milk on Grana Padano cheese yield (CY) under field conditions. Twelve cheese-making sessions were carried out from February to December 2009 in a dairy cooperative of Grana Padano Consortium (Italy), for a total of 96 vats of milk processed. For each vat, samples of raw milk were collected and analysed for quality traits (fat, protein, and casein contents), pH, TA, and milk coagulation properties (MCP), measured as rennet coagulation time (RCT, min), curd-firming time (k20, min), and curd firmness (a30, mm). Cheese yield was expressed as kilograms of cheese per 100 kg milk transformed, and was measured after 2 d of drainage. Fat, protein, and casein contents were positively and strongly correlated with CY (coefficients of correlation, r = 0·72, 0·88, and 0·84, respectively; P < 0·001). Coagulation properties were moderately and significantly (P < 0·001) related to CY: milk that coagulated earlier and had stronger a30 was associated to greater CY. Cheese yield was analysed with a model that accounted for fixed effects of cheese-making day, fat and protein content, TA, and a30. Significance was found for all the effects (P < 0·05). Milk characterised by high values of a30 resulted in higher CY than milk with low values of a30, indicating that MCP could be used as indicators of cheese-making efficiency. Future research should investigate the relationships between MCP and quality of cheese, and explore the feasibility of including MCP in multiple component milk pricing system for Grana Padano cheese production.

Negli ultimi tre decenni la domanda globale di cibo, in particolare di proteine animali (carne, latte, uova), è aumentata in base alla crescita della popolazione che dovrebbe arrivare a 9 miliardi di persone entro il 2050. Questi alimenti rappresentano infatti un'importante fonte di energia, proteine di alta qualità, micronutrienti e vitamine. Pertanto, questo miglioramento potrebbe contribuire all'aumento della durata della vita e della domanda di cibo. Ciò ha costretto il settore agricolo ad un'ulteriore intensificazione che ha interessato anche la coltivazione di colture per l'alimentazione animale. Le produzioni agricole e zootecniche hanno un impatto ambientale rilevante, e questo argomento è oggetto di critiche e di indagini scientifiche anche per definire più accuratamente il loro contributo e le relative potenziali strategie di mitigazione, considerando anche che la fase agricola è il principale contributore dell'impatto ambientale della catena di produzione alimentare. Si riconosce infatti che il settore agricolo contribuisce direttamente al 21% delle emissioni totali di gas serra di origine antropica a livello mondiale e consiste per lo più di metano seguito da protossido di azoto e anidride carbonica. Queste emissioni sono per lo più associate alla produzione zootecnica, in particolare all'allevamento di ruminanti che contribuisce con le emissioni dirette di metano dovute alla fermentazione dei ruminanti e alla fermentazione del letame; la restante parte è composta da emissioni indirette dovute alla deforestazione, all'uso di energia e alla produzione di mangimi. Lo scopo di questa tesi è stato la valutazione dell'impronta ambientale nel settore zootecnico a diversi livelli di scala tematica. La filiera italiana della carne, gli allevamenti lattiero-caseari, un caseificio per la produzione di Grana Padano DOP e i singoli animali sono stati studiati per quantificare l'impronta ambientale. Nel primo lavoro è stata valutata la filiera italiana della carne con un approccio di analisi dei flussi di massa e di valutazione del ciclo di vita. In primo luogo, la quantificazione della carne è stata effettuata dalla macellazione al consumo domestico, partendo dal peso della carcassa fino alla carne realmente consumata. A questo livello si è tenuto conto della carne di bovini, suini, ovini e caprini, equidi e conigli. Durante la catena sono state quantificate anche le perdite di carne e i rifiuti. In particolare, i sottoprodotti di origine animale (SOA) sono stati quantificati per singole specie e classificati in base al rischio a livello sanitario secondo il regolamento (CE) 1069/2009. Secondo la categoria (Cat 1, Cat 2 o Cat 3), supponendo che tutti i SOA fossero destinati al processo di rendering, l'uso e lo smaltimento dei prodotti dopo rendering è stato identificato. L'analisi dei flussi di massa ha confermato come l'Italia sia un importatore netto di carne bovina e suina, mentre è autosufficiente per quanto la carne avicola. L'analisi dei flussi di massa rivela che nel 2013 sono stati consumati in Italia 2,86 Mt di carne. Questo valore equivale a 131 g/giorno/pro-capite e a 47,91 kg/anno/pro-capite di carne consumata. In percentuale la quantità totale di carne consumata è rappresentata dal 46% da carne suina, dal 28% di carne avicola, dal 23% di carne bovina e dal 3% di altre carni (coniglio, equini, ovini e caprini). Questo approccio ha permesso di quantificare anche sottoprodotti di origine animale (SOA) prodotti durante la fase di macellazione e gli scarti alimentari a livello di vendita al dettaglio e fase di consumo. La fase di macellazione è risultata essere la principale fonte di rifiuti, producendo il 48% di rifiuti originati nella filiera della carne. I risultati hanno evidenziato come i SOA siano già quasi completamente riutilizzati, compatibilmente con il loro rischio a livello sanitario, dimostrando la circolarità del sistema e permettendo di quantificare anche i prodotti evitati grazie al loro riutilizzo e le relative emissioni di gas serra evitate. Per quanto riguarda gli altri rifiuti alimentari, i risultati della presente valutazione possono essere considerati solo una stima per la mancanza di specifici coefficienti nazionali. Dopo la fase di quantificazione, è stato applicato l'approccio del Life Cycle Assessment (LCA) per valutare l'impronta ambientale, considerando anche il prodotto evitato grazie al riutilizzo dei sottoprodotti del rendering. I risultati dell'LCA rivelano che il consumo giornaliero di carne pro-capite emette 4,0 kg di CO2eq, con un contributo della care bovina pari al 30%, della carne suina pari al 9.6% e della carne avicola pari all’8%. Le emissioni relative ai SOA sono risultate essere pari al 60% di quelle totali e il loro riutilizzo ha permesso una riduzione di queste del 10%. Il secondo ed il terzo lavoro sono stati invece relativi al potenziale di riscaldamento globale (GWP) di latte bovino e Grana Padano DOP. Complessivamente sono stati valutate ventisette aziende zootecniche con bovine da latte, con latte destinato al formaggio Grana Padano DOP, e un caseificio, situato nella provincia di Piacenza. I dati primari sono stati raccolti utilizzando un questionario appositamente redatto. Questo ha incluso per le aziende agricole la richiesta di dati relativi alla composizione della mandria, la gestione dell'alimentazione, la produzione di latte e performance riproduttive, piani colturali e l'utilizzo delle risorse energetiche e dei materiali di lettime, mentre per il caseificio sono stati richiesti dati relativi all'utilizzo delle risorse energetiche e gli input richiesti dal processo di caseificazione. Nel secondo lavoro sono state valutate 10 aziende lattiere per valutare l'impronta di carbonio del latte (CF) e individuare le principali fonti di emissioni. Lo studio ha utilizzato un approccio dalla culla alla tomba considerando come unità funzionale un 1 kg di latte corretto per contenuto di grasso e proteine (FPCM). Il valore medio di CF di 1 kg di FPCM è risultato essere pari a 1,33 kg di CO2eq/kg FPCM con però un ampio range di variazione, da 1,02 a 1,62 kg di CO2eq/kg FPCM. Le emissioni dovute alle fermentazioni enteriche e alle fermentazioni da reflui rappresentano il 52% del totale, mentre le emissioni relative agli alimenti acquistati il 36%. L'autoproduzione e il consumo energetico rappresentano invece rispettivamente il 6% e il 6%. Nel terzo lavoro invece è stata presa in considerazione la produzione di Grana Padano DOP. In questo caso è stato utilizzato un approccio dalla culla al cancello del caseificio considerando come unità funzionali 1 kg di FPCM e 1 kg di Grana Padano DOP stagionato 9 mesi. Il latte destinato alla produzione del formaggio ha mostrato un valore medio di CF pari a 1,38 kg CO2eq/kg FPCM, con un valore minimo di 1,02 e uno massimo di 1,94 kg CO2eq/kg FPCM. Il valore medio di CF di 1 kg di formaggio Grana Padano DOP è stato invece pari a 9,99 kg di CO2eq, con un contributo della fase agricola pari al 94%. I risultati di questi lavori si sono mostrati in accordo con studi simili riportati in bibliografia e hanno inoltre permesso di evidenziare come gli allevamenti da latte mostrassero un maggior livello di sostenibilità ambientale ma con possibilità di miglioramento principalmente attraverso il miglioramento della gestione delle mandrie (prestazioni produttive e riproduttive). Il quarto lavoro ha riguardato invece lo sviluppo di proxy in grado di prevedere le emissioni di metano da singole bovine da latte. Questo focus è un punto caldo di ricerca, soprattutto perché di fondamentale importanza per individuare strategie di mitigazione efficaci per la riduzione delle emissioni di metano dovute a fermentazioni ruminali, gas ad effetto serra riconosciuto avere il maggior contributo sul totale delle emissioni. Le emissioni di metano dipendono principalmente dal quantitativo di concentrato assunto e dalla composizione generale della dieta, ma tuttavia nelle aziende agricole commerciali risulta difficile quantificare con precisione l’ingestione di alimenti. Lo studio ha quindi mirato a verificare la possibilità di utilizzare la tecnologia del vicino infrarosso (NIRS) utilizzando lo spettro di campioni di feci (NIRSf) e/o in combinazione con altri parametri fenotipici disponibili a livello aziendale per prevedere la produzione di metano (MP, g/giorno) dalle singole vacche da latte in lattazione. Il NIRSf da solo ha permesso una stima abbastanza buona della produzione di metano e le stime sono state migliorate in misura simile quando sono stati considerati il peso vivo o la produzione di latte tal quale o la produzione di latte corretta per il contenuto energetico, mentre la combinazione del NIRSf con più di un altro parametro ha migliorato le stime solo in misura molto limitata. Il metano può essere previsto utilizzando modelli che considerano l’ingestione di sostanza sezza, il peso vivo o la produzione di latte ma il limite principale è rappresentato dalla disponibilità dei dati a livello aziendale. La tecnica del vicino infrarosso applicata ai campioni fecali, in particolare se combinata con altri parametri fenotipici, può rappresentare una valida alternativa per misurazioni su larga scala in allevamenti da latte commerciali, quando l’ingestione di sostanza secca di solito non è disponibile, per la selezione genetica di vacche da latte a bassa emissione.
In the last three decades global demand of food, in particular animal proteins (meat, milk, and eggs), has increased according to the population growth, that is expected to go up to 9 billion by the 2050. These, in fact, represent an important source of energy, high-quality protein, micronutrients and vitamins. Therefore, this improvement could contribute to the lifespan increase and food demand. The latter forced the agricultural sector to a further intensification that affected also the cultivation of crops for animal feeding. Agricultural and livestock productions have a relevant environmental impact, and this topic is object of criticism and scientific investigation also to more accurately define its contribution and potential mitigation strategies, considering also that agricultural stage is the main contributor to the environmental impact of the food production chain. It is recognized, in fact, that agricultural sector directly contribute to the 21% of total global anthropogenic greenhouse gas emissions, mostly consisting of methane followed by nitrous oxide and carbon dioxide. These emissions are mainly associated with the livestock production, in particular with ruminants breeding that contributes directly to methane emissions due to ruminal and manure fermentation; the remaining part is composed by indirect emissions from deforestation, energy use and animal feed production. The scope of this thesis was the evaluation of environmental footprint in the livestock sector at different subject scale level. Italian meat supply chain, dairy farms, Grana Padano PDO cheese factory and single animals was investigated in order to quantify environmental footprint. In the first work, the Italian meat supply chain has been evaluated whit a mass flow analysis (MFA) approach and life cycle assessment (LCA) approach. Firstly, the quantification of meat had been made from slaughter to household consumption, starting form carcass weight to real meat consumed. At these levels, meat form cattle, pig, sheep and goat, equidae, and rabbit was taken in account. During the chain also meat losses and waste were quantified. In particular animal by-products (ABPs) were quantified for single species and categorized into heath level risk according to the Regulation (EC) 1069/2009. According to the category (Cat 1, Cat 2 or Cat3), assuming that all ABPs were destinated to rendering process, use and disposal of rendered products was identified. The MFA confirmed how Italy is a net importer of cattle and pork meat while it is self-sustaining for poultry meat. Mass flow analysis revealed that in 2013, 2.86 Mt of meat were consumed in Italy. It is equivalent to 131 g/day/pro-capita and to 47.91 kg/year/pro-capita of meat consumed. In percentage the total amount of consumed meat is represented by 46% of pig, 28% of poultry and 23% of cattle and 3% of other meat (rabbit, equidae, and sheep and goat). This approach quantified the ABPs produced at slaughtering level and food wastes at retail and consumer levels. Slaughter phase was the main source of waste, producing 0.80 Mt of ABPs, 48% of the total amount of waste originated in the meat supply chain. Results highlighted how the ABPs are already almost completely reused, compatibly with their health level risk, demonstrating the circularity of the system through the quantification of the avoided products and relative GHGs emissions. Concerning other food wastes, the results of the present evaluation could be considered only an estimate due to the lack of specific national coefficients. After quantification LCA was applied in order to evaluate environmental footprint, considering also avoided product due to the re-use of rendered ABPs. LCA results reveal that daily meat consumption pro-capita emits 4.0 kg CO2eq represented by 30% of cattle meat, 9.6% of pig meat and 8% of poultry meat. Emissions allocated to ABPs are the 60% and their re-use decrease the emissions about 10%. Second and third works focused the milk and PDO Grana Padano global warming potential (GWP). Overall, twenty-seven dairy farms, producing milk destinated to Grana Padano PDO cheese and one cheese factory, situated in the Piacenza province were evaluated. Primary data were collected by using a specific survey. This included for the farms the request of data regarding herd composition, feeding management, milk production, herd management and performace, crops cultivation and resource use, whereas for the cheese factory, the survey included energy resource use and input requested by cheese making process. In the second work, 10 dairy farms were evaluated in order to assess the milk Carbon Footprint (CF) and the main source of emissions. The system boundary was a cradle-to-farm-gate and functional unit is 1 kg of FPCM (Fat and Protein corrected milk). The CF of 1 kg of FPCM resulted equal to 1.33 kg CO2eq/kg FPCM with a wide range of variation from 1.02 to 1.62 kg CO2eq/kg FPCM. Emissions due to enteric fermentation and manure fermentation represented the 52% of the total, while acquired feed the 36%. Self-production and energetic consumption represented 6% and 6% respectively. In the third, Grana Padano PDO production was considered. The milk destinated to cheese processing showed an average value of CF equal to 1.38 kg CO2eq/kg FPCM, with a minimum value of 1.02 and a maximum one of 1.94 kg CO2eq/kg FPCM. Instead, the CF average value of 1 kg of PDO Grana Padano cheese was equal to 9.99 kg CO2eq, showing an agricultural stage contribution of 94%. Results of these works were in accord with similar studies reported in literature and had pointed out how dairy farms showed a greater level of environmental sustainability but with possibilities for improvement, mainly through herd management enhancement (productive and reproductive performances). Fourth work was about the development of proxies able to predict the methane emissions from individual cows. This focus is a hot research point in order to improve the mitigation strategies to reduce methane emissions because of the main GHG contributor. Methane emission is mainly driven by feed intake and diet composition, but it is difficult to measure intake in commercial farms. The study aimed to verify the possibility of using NIRS of faeces (NIRSf) alone and in combination with other phenotypic parameters available at a farm level to predict methane production (MP, g/d) from individual lactating dairy cows. NIRSf alone allowed a fairly good estimation of methane yield and the estimations were improved to a similar degree when BW, MY or ECM were considered, whereas combining NIRSf with more than one other parameters improved the estimations with a very little extent only. Methane can be predicted using models that consider the DMI, BW or MY but the main limitation is represented by the data availability. Near Infrared technique applied to faecal samples, in particular when combined with other phenotypic parameters, can represent a valid alternative for large-scale measurements in commercial dairy farms for genetic selection of low emitters dairy cows, when DMI measurement is usually not available.

This thesis project was designed to explore the technological, chemical and microbiological factors involved in the late blowing defect (LBD) of Grana Padano (GP) with the aim of setting up every possible precaution to overcome this economically important flaw. LBD is a cheese defect caused by some Clostridium species, mostly Clostridium tyrobutyricum, and characterized by holes, cracks as well as an unpleasant flavour. Natural creaming of milk is the first and most critical step in GP making, during which C. tyrobutyricum spores are risen to the top of milk together with fat globules, thus being eliminated from partially skimmed milk. This step has been thoroughly investigated with particular reference to the interaction type between spores and fat globules. Transmission Electron Microscopy (TEM) revealed an electron-dense material sticking bacteria to fat globules. This material has been identified as immunoglobulins, mainly IgA and to a lesser extend IgM, by immunogold labelling. Many IgA molecules, but not IgM and IgG, were localized on C. tyrobutyricum cell wall suggesting the presence of anti-IgA receptors on it. Following this finding, immunoglobulins were purified from colostrum and their ability to enhance bacteria rising during natural creaming of milk investigated. Indeed, the addition of immunoglobulins led to a significant increase in spore rising with respect to untreated control. Specific natural creaming trials were also carried out to study the effect of creaming temperature on fat microstructure. Fat supramolecular organization, the unwanted fat globule structural rearrangement, was observed when creaming was carried out at 22 and 40 °C, as well as in sample tempered at 37 °C prior to the normal creaming at 8 °C. This suggests that the often-adopted thermal treatment before creaming is deleterious for fat microstructure. The behaviour of C. tyrobutyricum throughout the further steps of GP making and ripening was also investigated by an innovative approach. Vegetative bacteria cells and spores, independently sealed within dialysis tubes, were kept in the vat for the entire cheese making and then into the cheese over 6-month ripening. They were sampled and counted at milk renneting, curd cooking, curd extraction, in-mould acidification, brine salting, 3- and 6-month ripening. Furthermore, their morphological changes were monitored by TEM and the free amino acid utilization evaluated. Vegetative bacteria cells died during curd cooking up to 54 °C and then were no longer cultivable. However, 2 x 102 CFU/mL of these cells were sporulated in the curd at extraction and a higher number of spores was found at the end of 6-month ripening. Few spores germinated during curd acidification, when lactate was available. C. tyrobutyricum proved to convert arginine to citrulline and then to ornithine throughout the cheese ripening. This capability was confirmed in both milk and cheese model systems, indicating the vitality and metabolic activity of bacterial cells and, possibly, their ability of modifying GP sensorial properties. Lysozyme (LZ) is used in GP as well as in other cheese varieties to prevent the LBD. Thus, it has been considered important to verify its effects on lactic acid bacteria population and cheese free amino acid pattern. This study was carried out in 16 raw-milk hard cheeses produced in eight parallel cheese makings conducted at four different dairies using the same milk with (LZ+) or without (LZ-) addition. LZ- cheeses were characterized by higher numbers of cultivable microbial population and lower amount of DNA arising from lysed bacterial cells with respect to LZ+ cheeses. At both 9 and 16 months of ripening, Lactobacillus delbrueckii and L. fermentum proved to be the species mostly affected by LZ. The total content of free amino acids indicated that the proteolysis extent is characteristic of each dairy, regardless to the presence of LZ. Instead, in LZ+ cheeses, microbial degradation of arginine into citrulline and ornithine was always promoted. As, the amount of ornithine was quantitatively lower than citrulline it is likely that the arginine-deiminase pathway was only partially adopted. Working with C. tyrobutyricum spores gave rise to the need of a practical and effective staining method that could both facilitate spore detection and easily discriminate spore from vegetative bacterial cells. A fast and robust protocol for fluorescent staining of spores and vegetative cells of C. tyrobutyricum was set up, by using Hoechst 34580 and Propidium Iodide (HO/PI) stains that allowed to distinguish viable, dead and sporulated cells of C. tyrobutyricum. The HO/PI staining protocol proved to be suitable for other three Clostridia that can cause LBD: C. butyricum, C. sporogenes and C. beijerinkii. Furthermore, Hoechst 34580 dye was successfully used, together with Nile Red and Fast Green, to observe spores into the cheese matrix. In this case, spores were experimentally added to milk during cheese making and the triple staining was performed on slices of cheese after a month ripening. Finally, during the investigations related to this thesis project, it was possible to shed light on other inclusions present in GP matrix during and after ripening, such as specks, spots and microcrystals. Light microscopy revealed that the small, hard specks had the structure of crystalline tyrosine, as confirmed by amino acid analysis. Spots showed a complex structure, including several curd granules, cavities, and microcrystals, and were surrounded by a dense protein layer. Spots contained significantly less moisture and ash than the adjacent cheese area, and were significantly richer in protein, including significantly higher levels of valine, methionine, isoleucine, leucine, tyrosine and phenylalanine. Microcrystals were observed by light and electron microscopy and analysed by confocal micro Raman. Among others, calcium phosphate crystals appeared to consist of a central star-shaped structure immersed in a matrix of free fatty acids besides leucine and phenylalanine, in free form or in small peptides. A hypothetical mechanism for the formation of these structures was also formulated.

Qualsiasi prodotto alimentare che si trova sul mercato contiene diverse etichette che aiutano i consumatori nel loro processo decisionale quando fanno acquisti. Questo aiuto può essere garantito solo se i consumatori comprendono il significato di queste etichette, le differenze tra loro e le informazioni che certificano. La tesi ha esplorato il ruolo delle etichette nel settore del marketing alimentare usando studi condotti sull'approccio del consumatore. Utilizzando diversi metodi (statistici ed econometrici), abbiamo analizzato le percezioni, la consapevolezza e la conoscenza dei consumatori verso alcune etichette alimentari e le loro preferenze e comportamenti verso i prodotti alimentari che portano queste etichette (etichette nutrizionali sul fronte della confezione e marchi di qualità europei). I prodotti alimentari certificati di qualità sono stati scelti perché sono drammaticamente rilevanti per il settore agroalimentare europeo, e ancora di più per quello italiano dove costituisce la DOP Economy, data la sua densità. Sulla base dei risultati abbiamo formulato alcune raccomandazioni di marketing, policy, e di comunicazione che potrebbero essere utilizzate dai consorzi per migliorare l'impegno dei consumatori per i prodotti con marchi di qualità. Le raccomandazioni sono state rivolte anche ai policy maker e ai produttori dei prodotti DOP/IGP/STG/Organici ma anche ai policy maker dell'Etichettatura Nutrizionale.
Any food product found on the market contains several labels that help consumers in their decision making when shopping. This help can be guaranteed only if the consumers understand the significance of those labels, the differences between them and the information that they certify. The thesis explored labels’ role in the food marketing sector and studies were carried out according to consumer approach. Using different methods (statistics and econometrics), we analyzed consumers perceptions, awareness, knowledge towards some food labels and their preferences and behavior toward food products bearing these labels (Front of Packaging Nutritional Labels and Quality labels). Quality certified food products were chosen because are dramatically relevant for the European agri-food sector, even more of the Italian one where it forms the DOP Economy, due to its density. Assessments of several food labels from a consumer behavior perspective was carried out. Based on the findings we formulated some policy, marketing recommendations and communication suggestions that could be used by the consortia to enhance consumers’ engagement for products with quality certifications (PDO/PG/TSG or organic). The recommendations were also addressed to policy makers and producers of the PDO/PGI/TSG/Organic products but also to the policy makers of the Nutritional Labelling.