A ban on serving raw beef liver in restaurants in Japan has not decreased the number of E. coli infections in the country, according to a study.

Enterohemorrhagic E. coli (EHEC) causes many symptoms from diarrhea to the potentially deadly hemolytic uremic syndrome (HUS). Serving raw beef liver dishes at restaurants was banned beginning in July 2012 in Japan. Violations carry civil and criminal penalties. The ban came after an EHEC outbreak involving uncooked beef.

In April 2011, there was an outbreak of EHEC strains O111:H8 and O157:H7, involving 181 patients with 34 cases of HUS linked to contaminated Yukhoe (Korean-style steak tartare) at franchises of barbecue restaurants.

Researchers looked at the national reportable diseases database from January 2008 to December 2017. They also included additional regulation on raw beef red meat handling implemented in May 2011 and seasonality into their model. Findings were published in the journal BMC Infectious Diseases.

No significant reduction after ban
Incidence rate of EHEC infections in Japan was relatively low among developed countries before the ban, so any measures might have a relatively small impact to the already low rate, the researchers said.

There were 32,179 asymptomatic and 21,250 symptomatic EHEC infections including 717 HUS cases and 26 deaths during the study period. There was no apparent decrease in each category per million-people over time, according to the research report.

During the pre-intervention period before week 27 of 2012, there were 0.45 asymptomatic EHEC infections per million-people per week. The mean post-intervention infections were 0.51 per million-people per week.

For symptomatic EHEC infections, there were 0.30 cases per million per week during the pre-intervention period, and 0.33 cases per million per week after the intervention.

Public health policy
A warning advises consumers to cook beef liver fully for consumption with instructions to heat the core portion of meat to the temperature of 63 degrees C (145 degrees F) for more than 30 minutes or use methods such as heating for 1 minute at the core temperature of 75 degrees C (167 degrees F).

Beef meat consumption of Japanese per capita was largely stable during the study period.

The Japanese government implemented additional measures responding to sporadic foodborne outbreaks such as a ban on serving raw pork meats and liver in June 2015.

A variety of foods including meat, fruits and vegetables are also associated with EHEC infections so it is unlikely that banning a particular meat product will lead to a significant reduction in incidence, said researchers.

“The current study did not demonstrate a significant reduction in EHEC infections after implementing a nationwide ban on serving raw beef liver in the restaurant industry in Japan. Further study is needed to better guide public health policy to improve food safety including EHEC infections while accounting for culinary traditions and cultures,” they said.

(To sign up for a free subscription to Food Safety News, click here.)