Anti-Salmonella type 0-12 Group A, B, D Monoclonal antibody, Clone G03

Ground beef contamination with Escherichia coli is usually a result of carcass faecal contamination during the slaughter process. Carcasses are contaminated when they come into contact with soiled hides or intestinal leakage content during dressing and the evisceration processes. A more recent and compelling hypothesis is that, when lymph nodes are present in manufacturing beef trimmings, they can be a potential source of Enterobacteriaceae contamination of ground beef. The aim of this study was to investigate the occurrence of E. coli in lymph nodes from beef carcasses used for ground meat production, in six slaughter plants situated in central Italy A total of 597 subiliac (precrural) lymph nodes were obtained from 597 cattle carcasses and screened for E. coli by culture. Furthermore, E. coli isolates (one per positive carcass) were tested for stx1, stx2 eaeA and hlyA genes that are commonly used to identify and characterise shiga toxin-producing E. coli (STEC). In addition, the E. coli isolates were profiled for antimicrobial susceptibility. A proportion of 34.2% (204/597) carcasses were positive for E. coli. PCR revealed that 29% (59/204) of E. coli possessed stx1 or stx2 which corresponded to 9.9% of the cattle sampled. Moreover, a combination of stx1 or stx2 and eaeA was found in in 4 isolates (2% among E. coli positive samples and 1% among cattle sampled) and a combination of stx1 or stx2 and eaeA and hly in 1 isolate (0.5% and 0.2%). More than 95% of isolates were susceptible to gentamicin, ceftriaxone, cyprofloxacin and cefotaxime while high rates of resistance were recorded for cephalotin, ampicillin, tetracycline, tripe sulfa and streptomycin. The multivariate analysis identified "age" as the factor most closely related to E. coli positivity (either generic E. coli or STEC) in bovine lymph nodes. In conclusion, subiliac lymph nodes represent a source of E. coli for ground beef. These results are of major importance for risk assessment and improving good manufacturing practices during animal slaughter and ground meat production.

Raw egg-based dishes present a safety risk when eggs of uncertain Salmonella status are used. Here, the inactivation of four Salmonella serovars at different combinations of acid, pH and temperature were investigated. Strains of egg or broiler-associated Salmonella serovars Enteritidis, Infantis, Typhimurium, and a heat resistant Senftenberg 775W were tested in broth and egg yolk. It was observed that although S. Senftenberg 775W survived better than its mutant lacking the loci of heat resistance, the wild type per se was not acid tolerant. For all strains, egg yolk acidification with vinegar to pH 3.9 and storage at 25 degrees C or 8 degrees C resulted in >4Log(cfu/mL) reductions within 2h or 24h, respectively. At pH 4.2, 2-3Log(cfu/mL) reductions were seen within 6h at 25 degrees C. In contrast, acidification with lemon juice to pH of 3.9 allowed for growth at 25 degrees C, while a pH of 2.9 ensured >4Log(cfu/mL) reductions within 24h. Egg yolk and acid form the basis for many recipes and with a ratio of 0.82 of vinegar (>= 5% acetic acid) to egg yolk or 1.23 of lemon juice to yolk and storage at 25 degrees C for 2h or 24h, respectively, a high degree of safety can be obtained, if properly chilled raw eggs are used.