Can Eating Raw Scallions Really Give You Hepatitis A? The Truth Explained

Recently, an online message claimed that "scallions are actually the culprit behind liver disease in 3 out of 10 people in Yilan," and even "cilantro" was named a "culprit"; what is the truth? Experts say the hepatitis A virus is transmitted when unclean hands touch raw vegetables or seafood and then the virus is swallowed along with food; it has nothing to do with "which vegetable it is."

To reduce the risk of food poisoning, experts recommend giving priority to cooked food. If people want to eat raw scallions or other raw vegetables or raw oysters, experts suggest choosing a trustworthy production environment; leafy vegetables need to be separated leaf by leaf and washed under running clean water; more importantly, cooks must wash their hands before handling food; otherwise, viruses and bacteria from the human body will contaminate the ingredients just the same, and no amount of washing will help.

Is that fragrant pinch of chopped scallion really the culprit behind hepatitis A?

Hepatitis A is a disease caused by the "hepatitis A virus" and is mainly spread through "fecal-oral infection." Once someone fails to properly clean their hands after using the toilet and then touches food ingredients, or ingredients come into contact with contaminated water, and then these are eaten raw, the person can become infected with hepatitis A.

Nien Hsiao-ching, deputy chief executive of the Liver Disease Prevention and Treatment Research Foundation, said that any ingredient can cause infection if it is not washed clean, and that neither scallions nor cilantro are to blame.

"In fact, people in Taiwan, China over about 50 years old are not afraid of hepatitis A," Nien Hsiao-ching said. In earlier years, sanitation in Taiwan, China was poor, and most adults had had hepatitis A and therefore had antibodies; but as society progressed and the environment improved, people under 20 today do not have hepatitis A antibodies, so once they come into contact with the pathogen, they are easily infected.

Is there a difference between soil cultivation and hydroponics?

Besides the type of vegetable, does the cultivation method also make a difference in infection risk? Cheng Cheng-yung, emeritus professor in the Department of Horticulture at National Taiwan University, said that in earlier years in Taiwan, China, human feces were used as fertilizer for irrigation, so soil cultivation could indeed allow crops to be contaminated by viruses, but now that times and conditions have changed, this situation no longer exists.

As for whether "hydroponics," generally regarded as able to avoid soil contamination, can also avoid picking up hepatitis A virus, Cheng Cheng-yung said "not necessarily"; as long as the water used in hydroponics is contaminated, there is still a risk of transmission.

Kitchen workers should get vaccinated

According to statistics from the Centers for Disease Control, in recent years locally acquired hepatitis A has mostly been linked to eating raw oysters, clams and other shellfish and seafood; imported cases, on the other hand, have mostly occurred because people traveled or worked in countries with poorer sanitation conditions and brought the disease back to Taiwan, China. As of the end of July this year, there were 35 locally acquired hepatitis A cases this year, 17 imported cases, for a total of 52 cases; for all of 2014 there were 88 cases.

The Centers for Disease Control recommends that people traveling to countries with poor sanitation conditions pay attention to personal hygiene and get vaccinated in advance; as for eating seafood, cooked food should be preferred, and shellfish and seafood should be cooked until "the shells open" and then for another 3 to 5 minutes to ensure food safety.

Yeh Yen-po, director of the Changhua County Health Bureau, does not recommend that people eat food raw, and stressed that in addition to paying attention to personal hygiene and every step of the production process, kitchen workers can also receive the hepatitis A vaccine. "Once vaccinated, you can basically have lifelong immunity," and it can also prevent viruses lurking in an individual's body from accidentally infecting consumers and causing disease.

How can raw food be kept safe?

Although health experts mostly recommend that food be cooked, many people prefer to eat raw alfalfa sprouts, bean sprouts and cabbage. Therefore, Cheng Cheng-yung, emeritus professor in the Department of Horticulture at National Taiwan University, suggests that when buying vegetables to eat raw, people should choose safe, clean farms, and after buying them, separate the leaves and wash them carefully under running clean water.

In fact, the Food and Drug Administration has established the "Sanitation Standard for Raw Ready-to-Eat Foods" for "ready-to-eat raw foods" that can be eaten directly after opening; however, in May this year, the Food and Drug Administration additionally tested "raw sprouts that are not advertised as ready-to-eat but are easy to buy," and 39 of 40 samples had coliform bacteria levels that "did not meet ready-to-eat requirements."

Lin Tse-yang, section chief of food biology in the research and testing division that conducted this test, said that because there are often cases abroad of food poisoning caused by eating raw sprouts and vegetables, such as in 2011 in Germany, where eating raw bean sprouts was reported to have infected 3,000 people with enterohemorrhagic Escherichia coli and caused 37 deaths. Lin Tse-yang said, from a food safety perspective, the risk of cooked food is much lower than that of raw food.

He reminded that even if ingredients are thoroughly washed, if the person preparing the food "does not wear a mask, sanitary hat or gloves during cutting, viruses and bacteria from the human body may contaminate the ingredients; for example, Staphylococcus aureus in mucous membranes can also easily contaminate food," and all the previous washing effort goes down the drain just like the vegetable-washing water.

Quick facts on the hepatitis A virus:

How is it transmitted? Contact with virus-containing feces, or unclean hands or water touching food ingredients, allowing the virus to enter food.
What are the symptoms? Symptoms are similar to a cold: fever, vomiting and loss of appetite, and the average incubation period can reach 28 to 30 days.
How to prevent it? Get vaccinated; cook ingredients at 85 degrees Celsius for 90 seconds; shellfish and seafood need to be cooked until the shells open and then for another 3 to 5 minutes; when traveling to countries with poor sanitation conditions, get vaccinated in advance.