Recent reports suggest that the source of a 2022 Hepatitis E outbreak in China is suspected to have been undercooked pork liver.
In July and August 2022, an outbreak of Hepatitis E was reported at a nursing home in Hangzhou, Zhejiang Province.
A case-control study was conducted to identify risk factors for the spread of infection. Of 722 nursing home residents, 77 were diagnosed with Hepatitis E. Caregivers were the most affected, followed by care recipients and nurses. Of these, 18 showed symptoms such as jaundice, fever, and loss of appetite.
According to a study published in the International Journal of Food Microbiology, the average age of people infected with Hepatitis E Virus (HEV) was almost 60 years old, with 59 patients being women and 18 being men.
Between July 31 and August 10, 2022, three cases of Hepatitis E were reported at the nursing home, and the local Centers for Disease Control and Prevention dispatched personnel to the site to confirm the cases and conduct epidemiological investigations.
The first patient is a 59-year-old married woman who worked as a caregiver at a nursing home. In late July 2022, she developed symptoms such as loss of appetite, nausea, aversion to oily foods, fatigue, yellow urine, and jaundice of the eyes. On July 31, she was diagnosed with hepatitis E at the hospital. The second patient is a 59-year-old married caregiver who developed loss of appetite, yellow urine, and jaundice of the eyes on July 31. She was diagnosed with hepatitis E on August 2.
Case-control studies have shown that consumption of pork liver and raw fruits and vegetables provided in cafeterias are risk factors for the spread of this infection.
Cooking time and improper cooking methods
The researchers say their investigation found poor conditions in the nursing home's cafeteria and that the pork liver was cooked for too short a time. Surveillance video showed that cafeteria staff did not separate raw and cooked foods, and that the pork liver was cooked for only 2 minutes and 10 seconds. Other studies have shown that the inactivation time of HEV in the liver at 71°C (159.8°F) is more than 5 minutes.
Sanitation in the dining hall was poor, with cockroaches on the premises. Zoning was not strictly enforced and there was poor distinction between raw and cooked food. Although there were steamers to sterilize crockery, they were seldom used.
The researchers said that fruits and vegetables could become contaminated with HEV through the hands of cafeteria staff because raw and cooked foods were not properly separated.
No leftover food samples were collected from the canteen, and fresh pork liver samples collected from the supplier were negative for HEV.
Control measures included isolating and treating patients, implementing thorough cleaning and disinfection, and administering HEV vaccination after the outbreak.
“Canteen staff should be made aware of the importance of sufficient cooking times and temperatures when frying to ensure HEV inactivation. Other measures include strengthening hygiene controls in the food industry and recommending vaccination for high-risk groups,” the scientists said.
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