Marlene Janes, Bogren, Richard C. | 10/24/2006 1:00:40 AM
Outbreaks of foodborne diseases caused by fresh fruits and vegetables, such as the recent case of hepatitis A-contaminated green onions, are relatively rare in the United States.
But those outbreaks cause quite a stir when they occur – although experts say there’s little reason to worry about fresh fruits and vegetables if they’re handled with care.
"Bacteria or viruses can live on any type of fresh fruit or vegetable, but if you remove the outer skin, it’s safer," said Dr. Marlene Janes, a food microbiologist in the LSU AgCenter’s Department of Food Science.
Janes said one of the problems with hepatitis A is the 28-day incubation period between the time a person is exposed to the virus and the time the disease appears. "Then, it takes a long time to identify the source," Janes said
"Most other foodborne-related illnesses occur within 24 to 48 hours," she said. "People get sick, and we can stop it pretty quickly."
Janes said that although hepatitis A recently was in the news, other microorganisms such as salmonella can lurk on fresh produce, too.
The LSU AgCenter expert points out different microorganisms can be associated with various fruits and vegetables. In addition to hepatitis A with onions, other links include salmonella with cantaloupe, tomatoes or sprouts and E. coli with apple cider or lettuce.
Because salmonella frequently occurs on alfalfa sprouts and other fresh sprouts, the U.S. Food and Drug Administration has published guidelines for production of those vegetables. And it advises children, the elderly and persons with weakened immune systems against eating raw sprouts.
Salmonella on cantaloupe is a rather common problem, Janes said. She suggests washing the outer skin well with soap or dish detergent before cutting the fruit.
"Ground contact is often a likely cause of bacteria contamination due to contaminated manure or some of the bacteria naturally found throughout the environment," she said.
But fruits and vegetables that come into contact with the ground – or are grown in the ground – can react differently or have properties that protect them, Janes said.
"Green onions are particularly susceptible to hepatitis A – while carrots aren’t, because of the antimicrobial properties of carrots," the LSU AgCenter expert explained. "But many fruits and vegetables have skins that protect the food until they’re peeled."
Janes said people can practice good sanitation in their homes to prevent bacterial or viral diseases from occurring.
"For example, you can peel off the outer leaves of heads of lettuce or cabbage and then wash them with clean water to improve safety," she said.
"Our fruits and vegetables are relatively safe," the microbiologist said. "The problems we have usually are the result of improper handling of the fruits and vegetables during the processing or preparation of the produce. And they’re often hard to trace."
The LSU AgCenter microbiologist said many outbreaks of illnesses caused by fruits and vegetables stem from importing contaminated produce from countries with lower sanitation standards than the United States’.
"In the United States, when we have outbreaks of foodborne disease, we identify the problem, and then we fix the problem," Janes said.