Leafy greens are good for us because they have fiber and nutrients. But sometimes, they may contain harmful bacteria. It was mainly lettuce that caused the outbreak of the disease in the United States. A new study from the University of Illinois at Urbana-Champaign has identified the causes of E. coli bacteria infecting five leafy vegetables: roma lettuce, green leaf lettuce, spinach, kale and kale.
Lead author Dong is now a postdoctoral fellow at Duke University. Dong is a Ph.D. student in the Department of Food Science and Human Nutrition at the College of Agricultural, Consumer and Environmental Sciences.
The researchers tested how E. coli O157:H7 behaved on the whole leaves of five different vegetables. They kept the leaves at three different temperatures: 4 °C (39 °C (68 °F) and 37 °C (98.).6°f）。They found that temperature and the surface of the leaves, such as how rough they are, and whether they have a natural wax coating, can affect the likelihood that E. coli will stick to them.
When the temperature rises, E. coli multiply on lettuce, but when the temperature is maintained at 4 °C (39 °F), the number of coliform bacteria decreases rapidly. On the other hand, waxy vegetables such as kale and kale grow more slowly when warm. However, if it's already there, it can survive longer after refrigeration.
Still, kale and kale are less susceptible to E. coli infection than lettuce. Additionally, because kale and kale are usually cooked, unlike lettuce, which is eaten raw, the heat kills or inactivates E. coli. Washing lettuce helps a little, but it doesn't remove all the bacteria because they stick tightly to the leaves.
The researchers also tested what happens when E. coli O157:H7 is placed on a cut leaf compared to the whole leaf. "When a leaf is cut, it releases sap containing bacteria-like nutrients," Dong explains. However, they found that the juice of spinach, kale, and kale could fight E. coli. ”
They extract the juice from kale and kale to learn more and place it on lettuce leaves. They found that it could help kill bacteria. They believe the juice can be used to make sprays or coatings that fight harmful bacteria in food before and after harvesting.
Banerjee, an associate professor at FSHN and an extension specialist in Illinois, said, "We can't completely avoid bacteria in food. Vegetables grow in the soil, not in a sterile place, so there will be bacteria on them. ”
Banerjee and Dong want to clarify that they are not saying that people shouldn't eat fresh fruits and vegetables; They are essential for a healthy diet. Just follow food safety rules, wash lettuce, keep it in the refrigerator, and stay informed about any food recalls in your area.
Keeping lettuce in the fridge is key to preventing E. coli infection. This shows how important it is to store and handle food properly. Doing so makes it safer to eat leafy greens and reduces the chances of getting sick from E. coli in food.