A current research study from the University of Illinois Urbana-Champaign examines the elements affecting E. coli contamination in 5 various types of leafy greens: romaine lettuce, green-leaf lettuce, collard, spinach, and kale greens.”Even so, kale and collard are in general less prone to E. coli contamination than lettuce. These vegetables are typically prepared– which eliminates or inactivates E. coli– while lettuce is consumed raw. Washing lettuce does assist, Dong said, however doesnt get rid of all the germs since of their tight attachment to the leaf.The scientists also inoculated cut leaves with E. coli O157: H7 to compare the intact surface area of an entire leaf to the damaged surface area of a cut leaf.
By University of Illinois College of Agricultural, Consumer and Environmental Sciences April 17, 2024A new study checks out E. coli contamination in leafy greens, discovering that factors like temperature level and leaf attributes affect susceptibility. Lettuce is particularly vulnerable, but kale and collards show guarantee as less susceptible options due to their natural antimicrobial properties when cooked.Leafy greens are valuable for their dietary fiber and nutrients, yet they may also bring hazardous pathogens. Lettuce, in particular, has regularly been linked to foodborne illness break outs in the U.S. A current research study from the University of Illinois Urbana-Champaign examines the aspects affecting E. coli contamination in 5 various kinds of leafy greens: romaine lettuce, green-leaf lettuce, kale, collard, and spinach greens.”We are seeing a lot of outbreaks on lettuce, however not so much on kale and other brassica vegetables. We desired to discover more about the susceptibility of different leafy greens,” said lead author Mengyi Dong, now a postdoctoral research study associate at Duke University. Dong performed the research study as a doctoral trainee in the Department of Food Science and Human Nutrition (FSHN), part of the College of Agricultural, Consumer, and Environmental Sciences (ACES) at the U. of I.Findings on Temperature and Leaf Surface ImpactThe researchers infected entire leaves from each of the 5 veggies with E. coli O157: H7 and observed what took place after storage at 4 ° C (39 ° F), 20 ° C(68 ° F ), and 37 ° C(98.6 ° F). In general, they discovered that vulnerability was figured out by a mix of temperature level and leaf surface residential or commercial properties such as roughness and the natural wax finishing.”At space temperature or greater, E. coli grows really quick on lettuce, but if lettuce is refrigerated at 4 ° C(39 ° F ), we see a sharp decrease in the E. coli population. For waxy greens like kale and collard, we get the opposite results. On these vegetables, E. coli grows slower under warmer temperatures, however if it is already present, it can survive longer under refrigeration.”Even so, kale and collard are in general less prone to E. coli contamination than lettuce. These vegetables are generally cooked– which eliminates or suspends E. coli– while lettuce is taken in raw. Washing lettuce does help, Dong stated, but doesnt remove all the bacteria due to the fact that of their tight attachment to the leaf.The scientists likewise inoculated cut entrusts E. coli O157: H7 to compare the intact surface of an entire leaf to the harmed surface area of a cut leaf.”Whole leaves and freshly cut leaves present various scenarios. When the leaf is cut, it releases veggie juice, which contains nutrients that promote bacterial growth,” Dong discussed. The researchers discovered that spinach, collard, and kale juice in fact showed antimicrobial homes that secure versus E. coli.Potential Applications and ConclusionsTo even more explore these findings, they isolated juice (lysate) from kale and collards and used the liquid to lettuce leaves, discovering that it can be used as a natural antimicrobial representative. The potential applications could consist of antimicrobial spray or finishing to manage foodborne pathogen contaminations at both post-harvest and pre-harvest phases, the researchers said.”We cant entirely prevent pathogens in food. Veggies are grown in soil, not in a sterile environment, and they will be exposed to germs,” said co-author Pratik Banerjee, associate teacher in FSHN and Illinois Extension specialist.”Its a complex problem to solve, however we can accept best practices in the food market and food supply chain. Theres a great deal of interest from the research neighborhood and federal agencies to attend to these issues, and the USDA imposes high requirements for food production, so in general the U.S. food supply is quite safe.”Banerjee and Dong emphasize they do not desire to prevent people from eating fresh fruit and veggies; they become part of a healthy diet plan. Just follow food security guidelines, wash your lettuce thoroughly, store it in the refrigerator, and focus on any food security remembers in your area, they conclude.Reference: “Fates of connected E. coli o157: h7 on undamaged leaf surfaces exposed leafy green susceptibility” by Mengyi Dong, Maxwell J. Holle, Michael J. Miller, Pratik Banerjee and Hao Feng, 28 November 2023, Food Microbiology.DOI: 10.1016/ j.fm.2023.104432 This task was supported by the USDA Specialty Crop Block Grant Program (SCBGP) through the Illinois Department of Agriculture [grant numbers IDOA SC-22-20]