Salmonella Typhimurium is one of the main causes of outbreaks and sporadic cases of human gastroenteritis. At present, the rapid detection of this pathogen is a major goal of biosensing technology applied to food safety. In fact, ISO standardized culture method takes up to ten days to provide a reliable response. In this paper, we describe a relatively simple protocol for detecting Salmonella Typhimurium in chicken meat based on a Quartz-Crystal Microbalance (QCM), which leads to a limit of detection (LOD) less than of 10° CFU/mL and requires a pre-enrichment step lasting only 2 h at 37 °C. The reliability of the proposed immunosensor has been demonstrated through the validation of the experimental results with ISO standardized culture method. The cost-effectiveness of the procedure and the rapidity of the QCM-based biosensor in providing the qualitative response make the analytical method described here suitable for applications in food inspection laboratory and throughout the chain production of food industry.

The virulence of bacteria can be evaluated through both phenotypic and molecular assays. We applied these techniques to 114 strains of Salmonella enterica subsp. enterica collected from July 2010 to June 2012. Salmonella strains were of human origin (71/114) or isolated from food (43/114). The strain set included only the three predominant Salmonella serovars isolated in Italy from humans (S. Enteritidis, S. Typhimurium, S. 4,[5],12:i:-). These strains were screened via polymerase chain reaction for 12 virulence factors (gipA, gtgB, sopE, sspH1, sspH2, sodC1, gtgE, spvC, pefA, mig5, rck, srgA), while antimicrobial sensitivity was evaluated through the Kirby-Bauer assay. Fifty-nine different virulence profiles were highlighted; the genes showing the highest homology were those related to the presence of prophages (gipA, gtgB, sopE, sspH1, sspH2, sodC1, gtgE), while the genes related to the presence of plasmids were less frequently detected (spvC, pefA, mig5, rck, srgA). The Salmonella serovars Typhimurium and 4,[5],12:i:- were closely related in terms of both virulotyping and antibiotic resistance. S. Enteritidis showed higher antibiotic sensitivity and a higher prevalence of genes related to plasmids.

Fresh products are characterized by reduced shelf-life because they are an excellent growth medium for a lot of microorganisms. Therefore, the microbial spoilage causing significant food supply losses has become an enormous economic and ethical problem worldwide. The antimicrobial packaging is offering a viable solution to tackle this economic and safety issue by extending the shelf-life and improving the quality and safety of fresh products. The goal of this study was to investigate the effects of a food contact surface of polyethylene terephthalate (PET) functionalized with the previously characterized antimicrobial peptide mitochondrial-targeted peptide 1 (MTP1), in reducing the microbial population related to spoilage and in providing the shelf-life stability of different types of fresh foods such as ricotta cheese and buffalo meat. Modified polymers were characterized concerning the procedure of plasma-activation by water contact angle measurements and Fourier transform infrared spectroscopy measurements in attenuated total reflection mode (ATR-FTIR). Results showed that the MTP1-PETs provided a strong antimicrobial effect for spoilage microorganisms with no cytotoxicity on a human colon cancer cell line. Finally, the activated polymers revealed high storage stability and good reusability. This study provided valuable information to develop alternative antimicrobial packaging for enhancing and extending the microbial quality and safety of perishable foods during storage.