Survival of Salmonella in dried chicken meat residues on the surface of packaging materials

Salmonella contamination in raw chicken products may be transferred on materials used for meat packaging or re-packaging, which could then potentially serve as sources of cross-contamination of surfaces or foods in the home. This study evaluated survival of Salmonella in chicken meat residues on stored food packaging materials. Samples (5×5 cm) of aluminium foil, butcher paper, cardboard, PVC overwrap film, and vacuum bags were spot-inoculated (0.5 ml; 2-3 log CFU/cm2) with a 7-strain mixture of Salmonella suspended in a non-sterile raw chicken meat/water homogenate (10% wt/wt), simulating chicken meat purge. Materials were stored aerobically in petri dishes at 4 or 25°C, and were periodically analyzed (two replicates with three samples per material each time) for survivors on tryptic soy agar and XLD agar. Initial levels (2-3 log CFU/cm2) of Salmonella increased to 4-5 log CFU/cm2 within 4 days of storage at 25°C on all tested materials, except cardboard. After 123 days at 25°C, Salmonella was recovered from all the tested materials, with counts ranging from <0.82±1.09 (cardboard) to 4.79±0.70 (butcher paper) log CFU/cm2. Counts decreased on all materials stored at 4°C and reached non-detectable levels (<-0.40 log CFU/cm2) on cardboard and PVC overwrap film by day-39 and -53, respectively. Survivors of not more than -0.32±0.19 and -0.20±0.49 log CFU/cm2 were recovered from butcher paper and vacuum bags, respectively, after 88 days at 4°C. Salmonella can survive in food residues present on packaging materials for long periods of time. Thus, cross-contamination should be considered when handling or storing soiled packaging materials

Studio preliminare sulla diffusione di Staphylococcus aureus meticillino-resistente nella filiera suina

The aims of this study were (i) to estimate the prevalence of Staphylococcus aureus (S.a) in pig farm environments; (ii) to evaluate the presence of S.a in pork processing environments (iii) to detect the presence of methicillin-resistant (MRSA) among isolated strains. Samples of pig stool, farm environment and pork processing environment were collected. These samples were submitted to detection of S.a following the international method: UNI EN ISO 6888-2 and the Minimum Inhibitory Concentrations (MIC) tests were performed by using the automated VITEK 2 system. In addition, a PCR for the detection of the mecA gene was applied. Overall, S. aureus were more frequently detected from pig farms than from pork processing environments. Among the n.51 isolated strains, n. 49 (96%) were methicillin resistant (MRSA) and only n.2 strains were methicillin sensitive (MSSA). The results of the present study highlighted that further studies are needed to elucidate transmission routes of MRSA in pig production chain

Uso della spettroscopia NMR per la rivelazione del trattamento di irradiazione di prodotti a base di carne.

NMR profiling has been successfully employed for the authentication, geographical origin and varietal traceability of different foods. In this study the combination of 1H NMR lipid profiling with multivariate analysis was applied to differentiate non-irradiated and irradiated (0.5, 1, 2 and 3 kGy) dry fermented sausages. Two pattern recognition chemometric procedures, stepwise linear discriminant analysis (sLDA) and artificial neural networks (ANNs) were employed. sLDA provided a fair discrimination between the groups investigated. However, the recognition and prediction ability obtained by ANNs analysis was lower than that provided by sLDA. Contrary to raw meat, 1H NMR lipid profiling may not be considered a suitable screening tool for the detection of irradiated meat products in the laboratories appointed for the official control of food