Spinach and kale naturally fight food poisoning

Not all leafy greens face equal risk from dangerous bacteria. New research from the University of Illinois Urbana-Champaign and Duke University reveals why lettuce keeps making headlines in food poisoning outbreaks while kale and spinach rarely do.

Temperature makes the difference

Scientists infected whole leaves of various greens with E. coli O157:H7 bacteria and monitored bacterial growth under different temperatures. They discovered that temperature and leaf surface characteristics, such as roughness and natural wax coating, dramatically influence bacterial survival.

Lettuce showed rapid E. coli growth at room temperature around 68°F. However, refrigeration at 39°F significantly slowed this process.

Natural antimicrobial properties discovered

The most intriguing finding came when researchers examined vegetable juices released from cut leaves. While lettuce juice actually feeds harmful bacteria, spinach, kale, and collard juices demonstrated natural antimicrobial properties that actively fight E. coli contamination.

The research team even tested applying kale and collard juice to lettuce leaves as a potential natural food safety solution.

Why some greens stay safer

This discovery explains why we see frequent lettuce-related illness outbreaks but rarely hear about kale or spinach causing similar problems. The waxy surfaces of kale and collards provide additional protection against bacterial attachment, especially when these vegetables are typically consumed cooked rather than raw.

Practical food safety guidance

Lead author Mengyi Dong from Duke University emphasizes that this research doesn’t discourage vegetable consumption but instead informs better food safety practices. “We can’t completely avoid pathogens in food,” said study co-author Pratik Banerjee from the University of Illinois.

The findings support continued emphasis on thorough washing, proper refrigeration, and staying informed about food recalls to enjoy the nutritional benefits of fresh greens safely.

The study was published in the journal Food Microbiology.

—–

Like what you read? Subscribe to our newsletter for engaging articles, exclusive content, and the latest updates.

Check us out on EarthSnap, a free app brought to you by Eric Ralls and Earth.com.

—–