2024 年 41 巻 3 号 p. 103-112
In 2021, we quantitatively examined commercial chicken meat (56 samples) and liver (17 samples) for contamination with the hygiene indicator bacteria, Campylobacter and Salmonella. Campylobacter spp. was isolated from 14.3% (8/56) of meat and 17.6% (3/17) of liver samples; the predominant isolates were C. jejuni, and the Penner serotype was gB. One liver sample had a high value of ≥11,000 MPN/100 g, while the other samples were <999 MPN/100 g. Salmonella spp. were isolated from 17.9% (10/56) of meat and 35.3% (6/17) of liver samples; the predominant serovar was S. Schwarzenground (12 samples), followed by S. Infantis (3 samples) and S. Manhattan (1 sample). One liver sample showed a high value of ≥11,000 MPN/100 g, while the others were <999 MPN/100 g. Campylobacter isolates were susceptible to macrolides (Erythromycin), whereas Salmonella isolates were susceptible to fluoroquinolone (Ofloxacin) and cephem antibiotics (Cefmetazole), which appear to be effective treatments, but it is necessary to monitor trends in antimicrobial-resistant bacteria. The aerobic count (mean±standard deviation), Enterobacteriaceae count, coliform group count, and Escherichia coli count were respectively 4.59±1.01, 3.26±0.69, 3.14±0.64, and 1.62±0.70 log cfu/g in meat and 3.86±0.94, 2.74±0.89, 2.56±1.10, and 1.70±0.56 log cfu/g in liver. The risk ratio of Salmonella positive samples for aerobic count (≥ 4.0 log cfu/g),Enterobacteriaceae count and coliform count (≥ 3.0 log cfu/g) in chicken liver are 7.14, 9.17 and 9.17, respectively. The results suggest that aerobic bacteria count, Enterobacteriaceae count, and coliform group count might be useful for determining whether Salmonella is present in Liver, whereas the hygiene indicator bacteria could not be used to determine whether Campylobacter and Salmonella were present in chicken meat.
