The use of alternative feed ingredients in farm animal's diets can be an interesting choice from several standpoints, including safety. In this respect, this study investigated the safety features of selected former food products (FFPs) intended for animal nutrition produced in the framework of the IZS PLV 06/14 RC project by an FFP processing plant. Six FFP samples, both mash and pelleted, were analysed for the enumeration of total viable count (TVC) (ISO 4833), Enterobacteriaceae (ISO 21528-1), Escherichia coli (ISO 16649-1), coagulase-positive Staphylococci (CPS) (ISO 6888), presumptive Bacillus cereus and its spores (ISO 7932), sulphite-reducing Clostridia (ISO 7937), yeasts and moulds (ISO 21527-1), and the presence in 25 g of Salmonella spp. (ISO 6579). On the same samples, the presence of undesired ingredients, which can be identified as remnants of packaging materials, was evaluated by two different methods: stereomicroscopy according to published methods; and stereomicroscopy coupled with a computer vision system (IRIS Visual Analyzer VA400). All FFPs analysed were safe from a microbiological point of view. TVC was limited and Salmonella was always absent. When remnants of packaging materials were considered, the contamination level was below 0.08% (w/w). Of note, packaging remnants were found mainly from the 1-mm sieve mesh fractions. Finally, the innovative computer vision system demonstrated the possibility of rapid detection for the presence of packaging remnants in FFPs when combined with a stereomicroscope. In conclusion, the FFPs analysed in the present study can be considered safe, even though some improvements in FFP processing in the feeding plant can be useful in further reducing their microbial loads and impurity.

No abstract

This study evaluated the prevalence of potential pathogenic bacteria (mainly Campylobacter spp., but also Listeria monocytogenes and Salmonella) in wild boar (S us scrofa) and the hygiene of carcasses of wild boar hunted in a hill area of northern Italy during a hunting season (October to December). In total, 62 animals were submitted to microbiological analyses of the tonsils (detection of Listeria spp. and Listeria monocytogenes), caecal content (detection of Salmonella and Campylobacter spp.), mesenteric lymph glands (detection of Salmonella), and carcasses. In addition to analyzing pathogen prevalence and carcass hygiene of these animals, we performed an enumeration of total viable count (TVC), Enterobacteriaceae, Escherichia coli, coagulase-positive staphylococci, and spores of sulfite-reducing clostridia. Influencing factors considered were sex, weight, and age of the animals and environmental temperature on the day of hunting. A high prevalence was observed for L. monocytogenes in tonsils (35.3%) and for Campylobacter spp. in caecal content (51.8%), whereas Salmonella enterica strains (mainly serovar Thompson) were only occasionally isolated (7% in caecal content and 3.5% in lymph glands). The prevalence of L. monocytogenes was influenced by animal age and environmental temperature. Campylobacter spp. were the only pathogens detected on the carcasses (16.7%). Carcasses were characterized by low levels of contamination: TVC, 3.21 ± 0.80 log CFU/cm, Enterobacteriaceae, 1.32 ± 0.89 log CFU/cm; E. coli, 1.31 ± 0.93 log CFU/cm; and occasional detection of low counts of staphylococci and clostridia. TVC was positively influenced only by high environmental temperature, and higher Enterobacteriaceae counts were detected on heavy male carcasses than on females. The results confirmed the potential role of wild boars as reservoirs for the most important foodborne pathogens. But a low carcass contamination level is achievable if hunters are properly trained about hygienic carcass management and slaughtering procedures.

No abstract

pH is one of the most important parameters to manage bacterial replication in foodstuffs. In this study, the ability of 2 Bacillus cereus strains, 1 clinical human isolate (GPe2) and 1 isolate from a dairy product (D43), were investigated for in vitro growth at different pH values (from 3.5 to 7.5) at 2 temperatures (15 and 37°C), showing their ability to grow from 5.5 to 7.5 and from 5.0 to 7.5, respectively. The ability of spores of these 2 microorganisms to germinate in different typologies of dairy products (unflavored yogurt, Taleggio cheese, mascarpone cheese, and raw and pasteurized milk) was also investigated by inoculating the spores and maintaining the products at 15°C. No growth was observed in yogurt, likely due to the combined effect of low pH (<5) and the presence of natural microflora. An inhibitory action of the natural microflora on the growth of B. cereus was also hypothesized for Taleggio cheese and raw milk, as these substrates were characterized by a high natural lactic acid bacteria population and permissive pH values (5.8/6.8 in Taleggio cheese, >7 in raw milk). In pasteurized milk and mascarpone cheese, where pH was not restrictive for B. cereus growth and where no significant natural microflora was present, growth occurred rapidly up to loads close to 7 log cfu/g.