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The detection of Campylobacter, the most commonly reported cause of foodborne gastroenteritis in the European Union, is very important for human health. The most commonly recognised risk factor for infection is the handling and/or consumption of undercooked poultry meat. The methods typically applied to evaluate the presence/absence of Campylobacter in food samples are direct plating and/or enrichment culture based on the Horizontal Method for Detection and Enumeration of Campylobacter spp. (ISO 10272-1B: 2006) and PCR. Molecular methods also allow for the detection of cells that are viable but cannot be cultivated on agar media and that decrease the time required for species identification. The current study proposes the use of two molecular methods for species identification: dot blot and PCR. The dot blot method had a sensitivity of 25 ng for detection of DNA extracted from a pure culture using a digoxigenin-labelled probe for hybridisation; the target DNA was extracted from the enrichment broth at 24 h. PCR was performed using a pair of sensitive and specific primers for the detection of Campylobacter jejuni and Campylobacter coli after 24 h of enrichment in Preston broth. The initial samples were contaminated by 5 × 10 C. jejuni cells/g and 1.5 × 102 C. coli cells/g, thus the number of cells present in the enrichment broth at 0 h was 1 or 3 cell/g, respectively.

Brettanomyces bruxellensis is a current problem in winemaking all over the world, and the question if B. bruxellensis has a positive or negative impact on wine is one of the most controversial discussions in the world. The presence of live B. bruxellensis cells represents the risk of growth and an increase in cell numbers, which is related to the potential production of volatile phenols. In this work, the optimisation of a PMA-quantitative PCR (qPCR) method to enumerate only viable cells was carried out using the standard strain B. bruxellensis DSMZ 70726. The obtained detection limits were 0.83 log CFU/mL in red wine, 0.63 log CFU/mL in white wine and 0.23 log CFU/mL in beer. Moreover, the quantification was also performed by Reverse Transcription quantitative PCR (RT-qPCR), and the results showed a higher detection limit for all of the trials.

Malolactic fermentation is an important step in winemaking, but it has to be avoided in some cases. It's carried out by lactic acid bacteria belonging mainly to the genus Oenococcus, which is known to be a slow growing bacterium. Classical microbiological methods to enumerate viable cells of Oenococcus oeni in must and wine take 7-9 days to give results. Moreover, RT-qPCR technique gives accurate quantitative results, but it requires time consuming steps of RNA extraction and reverse transcription. In the present work we developed a fast and reliable quantitative PCR (qPCR) method to enumerate cells of Oenococcus oeni, directly, in must and wine. For the first time we used a propidium monoazide treatment of samples to enumerate only Oenococcus oeni viable cells. The detection limit of the developed method is 0.33 log CFU/mL (2.14 CFU/mL) in must, and 0.69 log CFU/mL (4.90 CFU/mL) in wine, lower than that of the previously developed qPCR protocols.

Mycotoxigenic moulds can grow on the surface of sausages and reduce the safety of these sausages for consumption. The aim of this study was to prevent the growth of Aspergillus ochraceus and the presence of Ochratoxin A (OTA) on the surface of Milano-type sausages using ozonated air. Spores of A. ochraceus were used to inoculate the casings of the sausages after casing. A portion of the lot (35 samples) was ripened in typical rooms, and another portion (35 samples) was dried and ripened in a separate room that was treated with gaseous ozone. The gas was delivered at night (8 h/day) at a concentration of ∼1 ppm. The temperature and relative humidity during the drying and ripening were the same for both rooms. Our results demonstrate that the gaseous ozone treatment prevented the growth of A. ochraceus and, consequently, the presence of OTA. In contrast, A. ochraceus grew and produced OTA on the untreated sausages. Moreover, the use of ozone did not influence the ripening, physico-chemical parameters, peroxide value or sensorial characteristics of the sausages.

The aim of this study was to compare the ecology of catalase-positive cocci (CPC) present in traditional fermented sausages produced using different breeds of pork, each of which was raised in two different environments and processed using two different technologies. Semi-quantitative molecular methods were used to determine bacterial identities. Almost all fermentations were characterised by a significant increase in CPC during the first few days of fermentation, reaching values of 105–106 cfu g−1 within 3 days. Staphylococcus xylosus and Staphylococcus equorum species, which were detected over the course of fermentation, were found to be the predominant population in all the monitored fermentation. Staphylococcus haemolyticus, Staphylococcus lentus, Micrococcus luteus, Macrococcus caseolyticus and Staphylococcus succinus were also present, but their concentrations were found to vary under the different experimental conditions. Using cluster analysis, we concluded that a plant-specific CPC ecology existed. In addition, the breed of pork used for production was found to influence the presence of some CPC species. However, from this study, it was not possible to reach the same conclusion regarding the breeding system used.

In Friuli, a Northeastern region of Italy, a blood sausage called Sanganel is produced by farmers, butchers, shops, and factories. This sausage is made with pork meat, boiled blood, lard, spices, and salt. It is stored at 4 ± 2 °C and usually eaten fresh or boiled within 14 days of its manufacture. Little is known about its microbial populations and safety for consumption. The aim of this study is to characterise the microbial populations and the physico-chemical parameters of Sanganel to establish its quality and the safety of consuming it. The microbial population of Sanganel is typical of meat products, and psychrotrophic enterobacteria and lactic acid bacteria (LAB) grow while it is stored. Enterobacteria produce total basic volatile nitrogen (TVB-N) and biogenic amines that, despite the presence of LAB, increase the pH of the sausage to approximately 6.9. Considering the concentrations of Enterobacteriaceae and TVB-N in the sausage, a shelf-life of 14 days is suggested. However, at 30 days the sausage is safe to eat and presents normal odours and flavours. In addition, boiling the sausage for 30 min before consumption eliminates the asporogenous microbial population.

The spore-forming genus Bacillus includes species of industrial, clinical and environmental significance. The possibility of differentiating between Bacillus cereus and Bacillus thuringiensis, toxin producers associated with illness, is a real need in monitoring potentially contaminated foods to understand the real distribution of B. cereus/B. thuringiensis in different outbreak cases. As the use of DNA comparison obtains clearer results than classical microbiological methods in distinguishing B. cereus from B. thuringiensis in this work PCR-TTGE (Temporal Temperature Gradient gel Electrophoresis), rep-PCR and RAPD-PCR methods have been compared to assess the intra- and inter-specific variability of B. cereus and B. thuringiensis. 80 strains of B. cereus and B. thuringiensis isolated from food, patients and pesticides were analyzed using a gyrB gene DNA sequence in TTGE; primer M13 in the RAPD-PCR and primers REP1DT and REP2DT in the rep-PCR methods. A widespread distribution of the electrophoretic profiles was obtained either for B. cereus or for B. thuringiensis using TTGE. rep-PCR and RAPD-PCR were not always able to group strains from the same origin or belonging to the same species. The fingerprints obtained with the rep- and RAPD-PCR methods confirm the high intraspecific variability present in B. cereus and B. thuringiensis indicating the difficulty to discriminate between these two species in outbreak cases.