Researchers at Texas A&M University have developed a way to pasteurize oysters without chemicals or heat using an electron beam. A study measuring the method’s efficacy on norovirus and hepatitis A appears in the June issue of the scientific journal Applied and Environmental Microbiology.
Hepatitis A is virus that causes a liver disease that can last for weeks or months, according to the Centers for Disease Control and Prevention (CDC). Symptoms include fever, fatigue, loss of appetite, nausea, vomiting, abdominal pain, dark urine, clay-colored bowel movements, joint pain and jaundice. Symptoms usually develop two to six weeks after exposure and can last up to six months.
Sometimes called “the stomach flu,” norovirus is an extremely contagious virus responsible for half of all foodborne illness outbreaks each year, according to the CDC. About 21 million Americans get sick from norovirius each year. Of those, 70,000 are hospitalized and 800 die, according to the CDC.
It can be spread from contact with an infected person or surfaces he or she has touched; or from contaminated food or water. The virus inflames the linings of the stomach and intestines causing stomach pain, nausea, and diarrhea and vomiting. It can cause serious illness in young children and older adults.
Oysters can become contaminated with norovirus or hepatitis A from being handled by a sick food service worker or from contamination in the waters where they were harvested. If eaten raw, oysters contaminated with either virus can make people sick.
Although the CDC recommends that all shellfish be cooked to an internal temperature of 140˚, many people enjoy raw eating oysters raw. Pasteurization is one way to address the health risk of raw foods. And it’s one of the electron beam or E beam applications being explored at the National Center for Electron Beam Research at Texas A&M University.
The U.S. Food and Drug Administration (FDA) has already approved E beam technology as a way to control Vibrio vulnificus, a naturally occurring bacteria in shellfish that can cause life- threatening illness or death. In this study, researchers measured E beam’s efficacy on different levels of viral concentration. They found that at high levels of contamination the E beam was able to reduce norovirus levels by 12 percent and hepatitis A levels by 16 percent and at more moderate levels of contamination the method was able to reduce norovirus by 26 percent and hepatitis A by 90 percent.
