Chicken is a potent source of Salmonella infection in humans. Occasionally, patients with severe Salmonella enteritis require antimicrobial therapy. Antimicrobials are used to prevent and treat bacterial infections in broiler and breeder farms. Herein, we investigated the prevalence and antimicrobial resistance of Salmonella in 337 vacuum-packed chicken breast products manufactured in Japan between June and December 2021. Salmonella was isolated from 287 samples (85.2%). Among the products from Eastern Japan, the lowest Salmonella prevalence was observed in those processed in September (65.6%), which was significantly (p < 0.05) lower than that in November or December. Among the products from Western Japan, the lowest Salmonella prevalence was observed in those processed in August (61.9%), which was significantly (p < 0.05) lower than that in June, November, and December. The most frequent serovar was Salmonella Schwarzengrund (223 isolates), followed by S. Infantis (53 isolates), S. Manhattan (9 isolates), and S. Enteritidis (1 isolate). High rates of antimicrobial resistance were observed for streptomycin (64.5%), kanamycin (50.2%), tetracycline (65.2%), nalidixic acid (11.5%), and trimethoprim (35.9%). Resistance rates against these five antimicrobials in S. Schwarzengrund isolates were markedly higher in the isolates from Western Japan than in those from Eastern Japan. All 287 Salmonella isolates were susceptible to ciprofloxacin which belongs to fluoroquinolones and cefotaxime which belongs to third-generation cephalosporins. Salmonella prevalence in chicken products in Japan was found to be extremely high; therefore, chicken meat should be thoroughly heated before consumption. In Japan, fluoroquinolones and third-generation cephalosporins are recommended as the first- and second-choice antimicrobials for patients with severe Salmonella enteritis, respectively. The results of this study show that administering fluoroquinolones or third-generation cephalosporins is an effective option for patients with Salmonella enteritis caused by consuming chicken meat, and efficient strategies for Salmonella management on broiler farms and chicken-processing plants need to be developed.

Exposure to cadmium tends to be higher in Japan than in other countries due to the wide spreading of ore deposits and many mines throughout Japan. The proximal tubule of the kidney is recognized as the most susceptible site to be affected by cadmium exposure. Food Safety Commission of Japan (FSCJ) considered it appropriate to investigate studies of the effects of cadmium intake on renal proximal tubular function using urinary β₂-microglobulin concentration of 1,000 μg/g creatinine as a criterion for the dysfunction. Based on these epidemiological studies, FSCJ established a tolerable weekly intake (TWI) of 7 µg/kg bw per week for cadmium. This value is derived from the results of actual dietary surveys and urinary β₂-microglobulin concentrations in Japan, and not from the results of application of blood or urinary cadmium levels to theoretical models. Therefore, no uncertainty factor is required. The estimated dietary intake of cadmium in 2022 was 2.03 µg/kg bw per week, approximately 30% of the TWI of 7 µg/kg bw per week. Therefore, it is unlikely that dietary cadmium intake in the general Japanese population would cause adverse health effects.