Targeted cleaning to improve hygiene at food plants

Cornell University research has found spoilage and foodborne illness could diminish by swiping the surfaces in commercial food processing plants with specially designed swabs.

The study, published in Applied and Environmental Microbiology, found the rapid-testing adenosine triphosphate (ATP) swabs — which produce a light similar to the glow of fireflies in the presence of microorganisms — can improve the environmental hygiene of food-processing facilities.

During food production, routine cleaning and surface sanitation are keys to help prevent microbial contamination in the end food products. Without such a sanitation regime, food from processing plants can become more vulnerable to spoilage, and people who eat that food may face greater risk with illness or death from foodborne pathogens.

“Food scientists know that for processing plants, visual inspection is not a reliable indicator of cleaning-protocol success,” said Randy Worobo, professor of food science in the College of Agriculture and Life Sciences (CALS) and faculty fellow at the Cornell Atkinson Center for Sustainability. “All food factory ‘ecosystems’ are prone to niches where microorganisms can hang out or where food residues can persist. We need to find them.”

Worobo and lead author Jonathan Sogin, a doctoral student in food science, in partnership with 3M Food Safety microbiologists, spent nine months testing samples collected from the processing environment in a commercial tofu manufacturing facility. The efficacy of an environmental monitoring program was examined using the 3M Clean-Trace Hygiene Monitoring and Management system for ATP monitoring, in combination with 3M Petrifilm Plates, for microbiological enumeration.

The team assembled a custom-designed plan to use an ATP swab test to check dozens of critical points in the plant after it had been cleaned. Following use, the ATP swab is placed in a luminometer instrument, where the bioluminescence of contaminants is detected.

The amount of light is transformed in the luminometer to relative light units, where this value is displayed on the instrument. If it exceeds a defined threshold value, the surface would be considered dirty and may indicate that cleaning operations were not performed properly.

Results show that targeted cleaning — demonstrated by ATP monitoring and verified by further microbiological tests — can improve the hygiene of food-processing facilities.

“If a plant supervisor is responsible for the cleaning crew and the supervisor says, ‘That’s not clean enough’, there might be an employee who thinks that the supervisor is picking on them,” Worobo said. “Instead, if you have a luminometer, like the 3M Clean-Trace system, that device removes the bias so that the cleaning crew itself can see the numbers. These methods become a quantitative way to ensure that they’re doing a good job.”

ATP monitoring and microbiological enumeration can verify and improve the efficacy of cleaning and sanitation practices, which can have a positive impact not only for the facility, but for product quality, Sogin said.

“This test can not only verify that the plant’s equipment and food-contact surfaces are cleaned and sanitised before starting food preparations, it can identify problematic situations. It helps you become a sleuth,” Worobo said. “But as a standard, the industry should be using this method to verify cleaning and sanitation programs. It’s key.”

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