Outbreaks of food-borne infections frequently occur, with greens being the most common culprit, with links to 40 serious outbreaks of E. coli bacteria between 2009 and 2018, According to a report published in the journal Emerging Infectious Diseases.
Among them, romaine lettuce is the most “infamous” vegetable, especially in 2018 when it was the cause of 2 large outbreaks of E. coli bacteria. According to the report, 54% of green leafy infections were associated with romaine lettuce, followed by spinach and American lettuce at 17% and finally cabbage, green leaves and kale each. Type is 4%.
There is no clear reason why romaine lettuce is so often the cause of bacterial infection outbreaks. Researchers note that American lettuce is harvested and sold more than romaine lettuce in the years 2009-2017.
Researchers believe that the shape and the growing process is the reason that romaine lettuce is more susceptible to infection than other vegetables.
The researchers wrote: “By the end of the study, romaine had become more common, people bought more romaine than lettuce. But that doesn’t explain why romaine is the cause. out of many such outbreaks “.
They hypothesized it was due to the shape of the romaine, which could be the point of entry for the pathogens because they were taller with bunched leaves, opening up at the top, while American lettuce was smaller with the Compact leaves.
Other outbreaks involved first mixed greens, lettuce, American and romaine lettuce, and a second blend of red cabbage, spinach and some spring vegetables.
The report focused on outbreaks of an E. coli bacterium called the Shiga toxin-producing E. coli, or STEC. This is a toxin produced by bacteria that causes illness in humans with symptoms that can include diarrhea and vomiting. Most people recover on their own within 5 to 7 days, but some dangerous cases still require medical attention.
During the decade of foodborne illness outbreaks in the United States and Canada, it reported 1212 illnesses, 420 hospitalizations and eight deaths, according to the report. A total of 77 cases of hemolytic urea syndrome, a kidney problem that can be caused by a bacterial infection and require hospitalization.
Shiga toxin-producing E. coli has been linked to approximately 265,000 cases per year in the United States. A special type of STEC, STEC O157, tends to make the condition worse and worse responsible for the 32 outbreaks described in the report. The most common sources of this infection are ground beef and green vegetables.
Although leafy greens are grown year round in the United States, more outbreaks start in October and April than any other month of the year. The study authors write unclear why seasonally outbreaks occur.
Benjamin Chapman, professor and food safety expert at North Carolina State University, said there are a number of reasons why green vegetables are particularly susceptible to E.coli contamination, starting with how they grow: Large lettuce production process is outside and requires a lot of water.
In the United States, it is mainly grown in areas with animals, which are also a source of bacteria. E. coli pollution can come from sources such as irrigation water, animals and treatment. We know from previous outbreaks that cross-contamination can occur with even a small percentage of bacteria. “
Once bacteria have entered a plant, it is difficult to remove, Chapman said. Product is washed 3 times in processing plants, and consumers can rinse 90-99% before starting to use, but that may not be enough depending on the degree of infection. And because lettuce is almost always eaten raw or undercooked, any bacteria can enter the body directly.
Huong Giang (Source: NBC News)