Researchers have looked into the levels and factors behind Campylobacter food poisoning associated with chicken in Japan.

To prevent campylobacteriosis, it is necessary to counteract sanitation hazards in the food chain at farms, processing facilities, distribution, retail and kitchens, according to the study published in Food Safety, an online journal published quarterly by the Food Safety Commission of Japan (FSCJ).

Although epidemiological data from the Ministry of Health, Labour and Welfare (MHLW) is based on passive surveillance, the number of incidents caused by Campylobacter jejuni and coli has increased since 1997, and they are the most common bacterial foodborne infection since 2003, replacing Vibrio parahaemolyticus and Salmonella spp. which had been responsible for most food poisoning in Japan.

Rise in eating raw chicken meat and liver
Between 1997 and 2018, the number of incidents and patients varied from 257 to 645, and from 1,551 to 3,439, respectively. One large outbreak involved 875 patients and was traced to sushi topped with raw or undercooked chicken at outdoor events in Metropolitan Tokyo and Fukuoka Prefecture in 2016.

Epidemiological investigations of Campylobacter infections have shown that chicken meat products are the most important source of infection. Consumption of raw chicken meat and liver is not common but has been increasing.

The expert committee on microorganisms and viruses at FSCJ revised the previous risk profile of Campylobacter jejuni and coli in chicken meat in 2018. The MHLW modified the Poultry Slaughtering Business Control and Poultry Meat Inspection Act in 2014 aiming at introducing the Hazard Analysis Critical Control Point (HACCP) system into poultry processing plants.

The Japanese government amended the Food Sanitation Act in 2018, requiring all businesses to implement hygiene control based on HACCP principles. This law has not set standards for edible raw chicken meat.

Campylobacter demographics
Campylobacter food poisoning in Japan shows seasonal fluctuation with a major peak in the rainy season of May to July and a minor peak in September, although incidence may still be high in winter. The incidence rate is higher in males than in females, with a peak in young people aged 10 to 20 years old. When location was known, outbreaks have commonly occurred in restaurants over the last decade.

Epidemiological studies have shown that fresh edible raw or undercooked chicken meat such as torisashi, which is sliced raw chicken meat, tataki, which is chicken meat burned only at the surface, and raw chicken livers and gizzards are mostly responsible for illness.

As the locations and climate in the northern and southern parts of Japan are different the structures of broiler houses and feeding systems are not the same. Large- and small-scale slaughtering facilities also have different processing measures.

“Despite the increasing importance of Campylobacter food poisoning in Japan, effective surveillance systems for determining the health and economic burden of human campylobacteriosis, or for providing baseline data for interventions, have not been established,” said researchers.

Campylobacter poisoning could be prevented by not eating edible raw meat, by cooking and avoiding cross-contamination with other foodstuffs, such as foods consumed without heating, via chopping boards, cooking ware or unwashed hands.

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