In vivo and in vitro effects of selected antioxidants on rabbit meat microbiota

The purpose of this study was to investigate the effect of dietary vitamin E or EconomasE™ supplementation on the growth of several background/pathogenic bacteria on rabbit carcasses and hamburgers during refrigerated storage. For 51days, 270 New Zealand rabbits received either a basal diet, or experimental diets enriched with 100 or 200mg/kg of vitamin E or EconomasE™. The bacteria studied were Salmonella, Listeria monocytogenes, Pseudomonas, Enterobacteriaceae, Escherichia coli, coagulase-positive staphylococci, plus both mesophilic and psychrotrophic aerobes. The growth of Listeria monocytogenes on contaminated patties was evaluated through a challenge test. The potential protective or antimicrobial effect of vitamin E or EconomasE™ on Listeria monocytogenes or Pseudomonas aeruginosa was assessed in vitro. Diet did not influence the concentrations of bacteria found on rabbit carcasses and developing on hamburgers. Vitamin E (in vivo and in vitro) and EconomasE™ in vivo had a protective antioxidant role, while EconomasE™ in vitro had strong antibacterial activity against Listeria monocytogenes, but not against Pseudomonas aeruginosa

Evaluation of Listeria monocytogenes growth in raw milk at refrigeration temperatures/Valutazione della crescita di Listeria monocytogenes in latte crudo a temperature di refrigerazione

Summary Raw milk consumption has significantly increased in the last few years and it represents a public health risk for the consumers since it can harbour pathogenic microorganisms. The psychrotropic bacterium Listeria monocytogenes was chosen to perform Microbiological Challenge Tests in raw milk at three levels of contamination (1, 10 e 100 cfu/mL) to evaluate its growth at 0\ub0C, 2\ub0C and 4\ub0C. It has been observed that raw milk contaminated with 1 cfu/mL is compliant with the limit of 100 cfu/mL, required by European regulations, for four days at all the tested temperatures. On the contrary, when the contamination is 4810 cfu/mL, raw milk accomplices the microbiological criterion only at 0\ub0C and 2\ub0C. In order to protect consumers health and observe the European food safety criterion, considering the different levels of contamination of Listeria monocytogenes, we advise to store raw milk between 0\ub0C and 2\ub0C

Survival of Listeria monocytogenes in ready-to-eat frozen meat broth/Sopravvivenza di Listeria monocytogenes in brodo di carne surgelato pronto

SUMMARY The survival of Li steria monocytogenes in ready-to-eat frozen broth was evaluated utilizing the Microbiological Challenge Test in order to confi rm the date of minimum durability of 12 months and demonstrate that the limit 100 cfu/g will not be exceeded during the product shelflife. The results show that the microorganism is not detected after 24h in samples artifi cially contaminated with 2 cfu/mL. In addition, its concentration decreases progressively even in food products with a higher level of contamination (102 and 104 cfu/mL) stored at both -18°C and -10°C. Consequently, if the bacterium concentration is ≤100 cfu/mL, this value is not exceeded during and after the date of minimum durability, which is confi rmed. Therefore, regarding Listeria monocytogenes, the food safety criterion of 100 cfu/g can be used instead of absence in 25 g, when the product is placed on the market during its shelf-life