The number of domestic foodborne outbreaks in China has increased over 10 years, according to a study.

Researchers analyzed the cause of household foodborne disease outbreaks from 2010 to 2020 using data from the National Foodborne Disease Surveillance System.

A total of 17,985 outbreaks, which resulted in 73,252 illnesses, 38,829 hospitalizations, and 1,269 deaths, were reported. Most episodes were from May to October, and the highest number occurred in July.

A similar study, published in China CDC Weekly, looked at outbreaks in catering facilities in the country using data from the same time period.

Wild mushroom problem
Fungi, mainly poisonous mushrooms, were the most implicated food category, with 8,873 household outbreaks. The second was toxic plants and their products, with 1,552. These include aconite, potherb, tung seed or oil, bitter bottle gourd, and Masang fruit. Fungi were the primary etiologic agent, with 31,125 illnesses and 736 deaths.

Household outbreaks rose from 118 in 2010 to 4,140 in 2020. Almost 700 outbreaks were from unknown food. Alcohol products caused the highest case fatality rate, found in the study published in the Foodborne Pathogens and Disease journal.

Salmonella was the top bacterial pathogen with 437 outbreaks, and the principal chemical agent was nitrite, causing 476 outbreaks. Pupal toxicants, tetrodotoxin (TTX), and saxitoxin were the leading poisonous animal toxins. Norovirus was the primary virus, with 13 outbreaks. The cause was unknown for more than 4,200 outbreaks with 75 deaths.

Plant saponin toxicants were mainly found in vegetables. Eggs and egg products were mostly contaminated by Salmonella, followed by meat and meat products with the same pathogen. Chemical pesticides were primarily found in vegetables.

Tackling the issues
Researchers said most poisonous mushroom outbreaks occurred in southwest China, including Yunnan, Hunan, and Guizhou provinces.

Outbreaks from vegetable products were mainly caused by improper processing. Inedibility and misuse, especially wrong identification, were the top contributing factors to illnesses related to poisonous mushrooms, mainly in southwest China. The leading cause of Salmonella contamination in meat and meat products was improper processing and poor storage.

“The reason is that wild poisonous mushrooms are similar in appearance to edible mushrooms, and it is difficult for ordinary people to distinguish edible mushrooms from poisonous mushrooms without proper equipment. This study showed that targeted interventions to reduce mushroom poisoning are critical in China,” said researchers.

“Severe and even fatal aconite root poisoning may occur after consuming herbal soups and foods prepared from aconite roots. If the raw preparations and large amounts of aconite root are used, even prolonged boiling may not have a protective effect.

“All regions should strengthen market surveillance and improve laboratory surveillance of pathogenic bacteria such as Salmonella in meat. Residents should raise their awareness of food safety and ensure meat safety by processing meat and raw foods separately and storing them safely.” 

Public health agencies should also boost the supervision of foodborne diseases to reduce the risks.

“Governments should strengthen supervision for provinces with a high incidence of foodborne diseases, especially during peak seasons. In addition, health education for household food handlers, such as proper food handling behavior and emphasis on kitchen hygiene, should be strengthened to improve residents’ awareness of food safety and effectively reduce the occurrence of foodborne diseases among families,” said researchers.

Scientists said it was necessary to change understanding around aconitum plants. Aconite roots are used to prepare herbal soups and meals for their beneficial health effects.

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