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Fluctuating Temperatures Increase E. Coli, Listeria Risk in Leafy Greens

A new study has found that fluctuations in temperature during transportation and retail sale of leafy greens negatively impacts both the product’s quality and microbial safety.

In a study published in the February issue of Journal of Food Protection, researchers looked at the growth of E. coli O157:H7 and Listeria monocytogenes in commercially bagged salad greens.

Over a 16-month period, a series of time-temperature profiles from thousands of bagged salads were obtained from five transportation routes covering four geographic regions, as well as during retail storage and display.

“Based on the simulation, both pathogens generally increased <2 log CFU/g during transport, storage, and display,” the authors wrote. “However, retail storage duration can significantly impact pathogen growth.”

They added that this was the first large-scale study in the U.S. to use commercial time-temperature profiles to assess the microbial risk of leafy greens and that it “should be useful in filling some of the data gaps in current risk assessments for leafy greens.”

© Food Safety News
  • Janine

    Yet another reason to grow your own or buy local, if you can afford it.

  • CA Leafy Greens LGMA

    Health experts emphasize that food safety is a shared responsibility that starts on the farm, but is important all along the supply chain. For fresh produce, particularly leafy greens which are often eaten in an uncooked state, proper food safety practices are critical to reducing foodborne illness. The California Leafy Greens Marketing Agreement is devoted to ensuring a set of science-based food safety practices are being following on leafy greens farms. But LGMA members lose the ability to protect consumers when the leafy greens they carefully produce leave their coolers in California and head to dinner tables around the world.

    We appreciate the work these scientists have done. Only through research can we hope to reduce the number of foodborne illnesses associated with leafy greens both in the field and during post-production handling. It’s clear the findings from this study can fill vital data gaps that will help retailers and transportation companies develop proper handling procedures that can prevent illness.

  • mauimina

    That is why the need for consumer education in handling food after purchasing is so important along with folks making sure through their choices that their immune systems are vital to resist any pathogen from invading ones system. Sterilizing the farm is not the answer!!!