Study looks at reducing salmonella risks for bulb onions 

New projects funded by the Center for Produce Safety are looking at production practices that might reduce the chance of salmonella contamination in dry bulb onions, according to a news release.

Although several studies have examined salmonella persistence on various produce items, little information is available about how the pathogen behaves on dry bulb onions, according to the release.

In 2020, the dry bulb onion industry faced its first significant outbreak of foodborne illness when red onions grown in California were epidemiologically linked to more than 1,000 cases of salmonellosis.

Researchers leading two projects hope to identify production practices that may contribute to salmonella contamination of bulb onions and steps growers can take to reduce potential food safety risks, the release said.

Joy Waite-Cusic, Ph.D., with Oregon State University, is heading the project titled “Assessing the potential for production practices to impact dry bulb onion safety.” Vijay Joshi, Ph.D., with Texas A&M AgriLife Research, is leading the project titled “Strategic approaches to mitigate Salmonella contamination of bulb onions.” 

Key takeaways from the projects so far, the release said, are: 

• Little information is available about how Salmonella behaves on dry bulb onions. 
• Field trials in Washington and Oregon found typical field curing of onions killed Salmonella surrogates applied during irrigation or in water used to mix crop protection materials.
• Texas researchers plan to conduct field trials to determine how bulb quality traits influence Salmonella internalization. The goal is to develop recommendations on onion crop management, harvesting, curing, storage and distribution that will help the industry minimize the risk of Salmonella contamination. 

More information on the Oregon State University research is found here, with the Texas A&M project described here.