The study examined the factors that affect E. coli contamination on five leafy greens, including romaine lettuce, green-leaf lettuce, spinach, kale, and collards. Researchers discovered that lettuce was far more susceptible to outbreaks of E. coli, but this was not the case with kale and other brassica vegetables. The likelihood of an outbreak was determined by a combination of temperature and leaf surface properties such as roughness and the natural wax coating.
Susceptibility of Leafy Greens to E. coli Outbreaks
Lettuce, particularly romaine and green-leaf varieties, was found to be more prone to E. coli outbreaks compared to other leafy greens like kale and collards. The researchers attributed this difference to the physical characteristics of the leaves.
Influence of Leaf Surface Properties
The study revealed that the roughness and natural wax coating of the leaves played a significant role in the likelihood of E. coli contamination. Leaves with a rougher surface and less wax were more susceptible to E. coli outbreaks, as these conditions can provide a more favorable environment for the bacteria to thrive.
Temperature as a Contributing Factor
In addition to leaf surface properties, the researchers also found that temperature was a crucial factor in determining the risk of E. coli outbreaks. Higher temperatures were associated with an increased likelihood of E. coli contamination on the leafy greens.