UMass Amherst Food Scientist Will Study Anti-Salmonella Strategies for Tomato Safety

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UMass Amherst Food Scientist Will Study Anti-Salmonella Strategies for Tomato Safety

(Media-Newswire.com) - AMHERST, Mass. - Assuring the safe handling and cleanliness of commercially grown tomatoes is the goal of a new, two-year grant to food scientist Lynne McLandsborough and colleagues at the University of Massachusetts Amherst. Her laboratory is one of 17 receiving grants from the Center for Product Safety, Davis, California, to improve food safety in growing and harvesting fresh produce.

Specifically, McLandsborough, an expert in bacterial growth, biofilm formation and cross-contamination from one surface to another, received $235,787 to begin this month studying the survival, transfer and inactivation of Salmonella bacteria on plastics used in harvesting tomatoes. Her UMass Amherst team includes food chemistry expert Julia Goddard and pomologist, or fruit expert, Wes Autio. Though tomatoes are treated like vegetables by many cooks, they are actually true fruits.

"Bacterial cross-contamination from one surface to another is a more complex problem than we once believed," says McLandsborough. Food scientists would like to better understand how moisture levels affect biofilms and bacteria dispersal, for example. It’s counter-intuitive, but there is some evidence now that less moisture in a biofilm makes it brittle and more easily shattered into tiny flakes that quickly disperse, she adds.

The new studies should yield new basic knowledge about how and under what conditions bacteria form biofilms on different surface types and provide practical, science-based guidelines on how to prevent cross-contamination.

At the UMass Amherst food lab, McLandsborough and colleagues will set up an experimental tomato-handling station modeled on those found in farm fields in California and Florida. But in the lab, the researchers will be able to change parameters, for example, comparing bacterial transfer rates on smooth vs. abraded plastic tubs and ramps and evaluating contamination rates between work gloves made of a variety of materials. In this way, they can determine where and when Salmonella most often hitches a ride onto the tomato’s outer skin and into the food supply.

McLandsborough, who is an expert in the bacterium Listeria, has documented its transfer rates from food handling equipment to cheese, bologna and other cold cuts in many previous experiments. The new work with Salmonella should reveal new knowledge about this process in a different organism. "While we’re not sure about the cross-contamination levels we’ll find with these new experiments in Salmonella and tomatoes, it’s clear that growers need to know the facts and how best to carry out a safe harvest," she summarizes.