Staphylococcus aureus (S.aureus) is a pathogenic bacterium capable of developing biofilms on food processing surfaces, a pathway leading to cross contamination of foods. The purpose of this study was to evaluate the ability of S.aureus to form biofilm on food processing surfaces (polystyrene and stainless steel) with regard to different temperatures (12 and 37°C) and cellular hydrophobicity. Biofilm assays were performed on n. 67 S.aureus isolates from food, food processing environments and food handlers and n. 3 reference strains (S.aureus ATCC 35556, S.aureus ATCC 12600 and S.epidermidis ATCC 12228). A strain-specific variation in biofilm formation within S.aureus strains tested was observed. At 37°C, n. 38/67 (56.7%) of strains were biofilm producer in at least one tested surface. A total of n. 25/38 (65.7%) of strains were biofilm producer on polystyrene whereas n. 24/38 (63.1%) were biofilm producer on stainless steel. Moreover, n. 11/38 (28.9%) of strains were biofilm producers on both selected surfaces. The majority of S.aureus strains which produced biofilms (n. 17/38-44.7%), were isolated from food environments. At 12°C, only one S.aureus strain from food handler (S.aureus 374) was biofilm producer. Cell surface hydrophobicity level increased with temperature. Additionally, a statistically significant difference (P<0.001) was found between hydrophobicity at 37°C and 12°C. Finally, the architecture of biofilm formed by S.aureus strains on polystyrene and stainless steel surfaces at selected temperatures was observed by scanning electron microscopy. The appearance of thick extracellular products in strongly (S.aureus ATCC 35556 - positive control) and the absence of those products in the non-biofilm producer (S.epidermidis ATCC 12228 - negative control) is presented

The foodborne pathogen Listeria monocytogenes is a concern in food safety because of its ability to form biofilm and to persist in food industry. In this mini-review, the issue represented by this pathogen and some of the latest efforts performed in order to investigate the composition of biofilms formed by L. monocytogenes are summarized.

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Listeria monocytogenes is a foodborne pathogen able to persist in food industry and is responsible for a severe illness called listeriosis. The ability of L. monocytogenes to persist in environments is due to its capacity to form biofilms that are a sessile community of microorganisms embedded in a self-produced matrix of extracellular polymeric substances (EPS’s). In this review, we summarized recent efforts performed in order to better characterize the polymeric substances that compose the extracellular matrix (ECM) of L. monocytogenes biofilms. EPS extraction and analysis led to the identification of polysaccharides, proteins, extracellular DNA, and other molecules within the listerial ECM. All this knowledge will be useful for increasing food protection, suggesting effective strategies for the minimization of persistence of L. monocytogenes in food industry environments.

BackgroundThere is a general consensus in recognizing that traditional meat inspection is no longer able to address the hazards related to meat consumption. Moreover, it has been shown that invasive procedures, such as palpation and incision, can increase microbial contamination in carcasses. For these reasons, legislations all over the world are changing meat inspection techniques, moving towards visual-only techniques. Hence, there was also the need to test visual-only inspection in pigs in Italy.ResultsA protocol for visual-only post-mortem inspection was produced together with a 24-class scheme used to record pathological lesions. A list of guidelines needed for univocal interpretation and classification of lesions was developed. To record lesions at the slaughtering line, a light instrument that is resistant to the slaughter environment was designed and then produced in collaboration with an electro-medical company. Six contracted veterinarians were chosen and trained. They performed visual-only post-mortem inspections on 231.673 heavy pigs in three different slaughterhouses of Northern Italy. Visual-only inspection was compared to traditional inspection on 38.819 pig carcasses. No relevant differences were found between the two systems.ConclusionsThe comparison between traditional and visual-only inspection showed that visual-only inspection can be adopted in pig slaughterhouse. The analysis of the performance of the veterinarians stressed the importance of standardization and continuous education for veterinarians working in this field.