Studies on Elucidation of the Risk of Food borne Diseases by Pathogenic Microorganisms in Chicken Meat and Recommendations for Reduction Measures

鶏肉類の病原微生物による食中毒リスクの解明と低減策への提言

Studies on Elucidation of the Risk of Food borne Diseases by Pathogenic Microorganisms in Chicken Meat and Recommendations for Reduction Measures

Degree Grantors 山口県立大学

This study was conducted to investigate the actual contamination of chicken meat with pathogenic microorganisms at each stage of the food chain, to clarify the risk of foodborne diseases, and to examine measures to reduce the risk.
The survey at the distribution stage revealed that Campylobacter was isolated from 35.7% of commercial chicken meat in Yamaguchi Prefecture, and that the contamination rate was high in specific parts such as liver and during the summer season. Genotyping of the isolates by the mP-BIT method confirmed the presence of pathogenic genes and a high level of contamination with fluoroquinolone-resistant bacteria, which are feared to make treatment of infectious diseases more difficult. These results suggest that the disinfection of commercial chicken meat distributed in this prefecture is not sufficiently reduced in terms of foodborne diseases risk by the time they reach the distribution stage. Therefore, it is important to prioritize risk reduction measures at the consumption stage of chicken meat, and it is necessary to further educate consumers on the prevention of foodborne diseases.
A survey at the chicken slaughtering stage showed that chicken meat shipped from a chicken slaughterhouse in Yamaguchi Prefecture was highly contaminated with Campylobacter, and that the disinfection of chicken meat by the cooling process using sodium hypochlorite at the facility was not sufficient to reduce the risk of foodborne diseases. In the future, it is necessary to improve sanitation management, such as the type of disinfectant, concentration used, and cooling time, in accordance with the actual conditions of the number of broiler processed and equipment at the facility. In addition, it was considered necessary to examine measures to prevent contamination of broiler at each production farm.
A survey of several farms at the production stage revealed that the Campylobacter-positive rate was 46.9% in the Chugoku region and 75.0% in the Kyushu region, and the Salmonella-positive rate was 84.4% in the Chugoku region and 89.3% in the Kyushu region. The different characteristics of the contamination status of farms and broiler flocks, the bacterial species and serotypes, genotypes, and the acquisition of drug resistance were observed in the different regions. Therefore, it is important to take regional characteristics into consideration when clarifying the risk of foodborne diseases of chicken meat and considering measures to reduce the risk. The investigation of contamination factors in farms and broiler houses suggested that although the environment inside and outside the broiler house and feed were not factors for Campylobacter invasion and spread, contamination spread to the feeding environment through feces of infected broiler after 5 to 6 weeks of brooding. In addition, continuous contamination of Salmonella was confirmed in the feeding environment, including the
bedding material (recycled fermented litter) of the broiler house. The results also suggested the spread of Salmonella through feed and workers. Therefore, it is necessary to strengthen measures to reduce the risk of food poisoning by improving farm broiler feeding hygiene management manuals and introducing hygiene management based on Hazard Analysis and Critical Control Point (HACCP). In particular, it is necessary to establish Critical Control Points for sanitary management of bedding (recycled fermented litter) and to verify fermentation temperatures and times that can completely destroy the bacteria.
In order to promote appropriate sanitary management based on HACCP at the chicken slaughtering and production stages, effective foodborne diseases risk reduction measures should be implemented at each stage of the chicken meat food chain based on the knowledge obtained in this study under cross-field collaboration and cooperation among various entities such as government health departments, livestock breeding departments, research institutes, businesses, and consumers. Based on the findings of this study, it is necessary to take effective measures to reduce the risk of foodborne diseases at each stage of the chicken meat food chain to ensure food safety and security.

Creators YAMAMOTO Tomoya