Researchers look at reducing Salmonella risks for bulb onions

Analysis funded by the Heart for Produce Security (CPS) is hoping to determine manufacturing practices that will contribute to Salmonella contamination of bulb onions and steps growers can take to cut back meals security dangers.

Salmonella on onions is a rising concern. This previous yr a Salmonella Oranienburg outbreak linked to complete, recent onions imported from Mexico sickened greater than 1,000 shoppers. The outbreak got here only a yr after greater than 1,000 shoppers had been sickened by Salmonella Newport from pink onions.

Manufacturing practices influence on dry bulb onion security
The primary challenge, titled “Assessing the potential for manufacturing practices to influence dry bulb onion security,” is led by Pleasure Waite-Cusic, Ph.D., with Oregon State College. 

“We’re simply attempting to determine what probably occurred so we’re in a position to perceive the dangers,” Waite-Cusic stated, referring to Salmonella outbreaks in 2020 and 2021 linked to bulb onions. 

This yr, the researchers performed onion discipline trials in Pasco, WA, and Ontario, OR, utilizing a three-strain E. coli cocktail as a Salmonella surrogate. These websites had been chosen to characterize various weather conditions.

Of their Washington trials, which used a yellow onion selection, they made the season’s final overhead irrigation software utilizing E. coli-contaminated water. Within the Oregon trials, utilizing pink and white onion varieties, the researchers used E. coli­-contaminated water to combine the season’s final pesticide or clay sunscreen software.

In each trials, the researchers monitored pathogen ranges after software because the onions matured and cured within the discipline for 30 days.

“Spoiler alert,” Waite-Cusic stated, “We simply collected the final samples, and all the pieces died. Over each discipline trials, just one onion out of 440 examined on the finish of discipline curing was nonetheless constructive for E. coli.” Discipline curing did an excellent job of mitigating contamination that occurred within the water functions, she stated.

“This doesn’t inform us the reply to the outbreaks, nevertheless it’s nice information for the trade and meals security.”

This winter, the researchers plan to conduct laboratory dye research to see if water utilized to the leaves of youthful vegetation can transfer into the tissue and probably pose a contamination entry route.

Extra concerning the examine could be found here.

Strategic mitigation
The second challenge, titled “Strategic approaches to mitigate Salmonella contamination of bulb onions,” is led by Vijay Joshi, Ph.D., with Texas A&M AgriLife Analysis. 

Joshi’s challenge seeks to raised perceive how Salmonella colonizes and enters onion bulbs. He additionally plans to determine manufacturing practices that will cut back plant susceptibility. 

The challenge proposes creating an onion-specific threat discount plan by investigating Salmonella’s survival and development on onion bulbs utilizing totally different genetic backgrounds, dietary compositions influenced by agronomic practices, seasons, and managed stress environments.

“Unlocking the genetic potential of vegetation to fight Salmonella is a novel avenue in bettering meals security,” he stated. 

Moreover, to grasp the potential of onions as a transient host for transmission, the researchers investigated the results of genetic, dietary, and physiochemical traits on Salmonella survival and development.

The researchers hope to offer the trade with instruments to determine elements in onion manufacturing and provide chain that will permit Salmonella to persist, determine varieties and agronomic practices that may reduce or get rid of its persistence, and assist the produce trade in creating pointers to handle dangers of Salmonella in onions successfully.

The researchers plan to conduct discipline trials to find out how bulb high quality traits — together with nitrogen content material, moisture degree, and macro- and micro-elements — affect Salmonella internalization.

Their objective is to develop suggestions on onion crop administration, harvesting, curing, storage, and distribution that may assist the trade reduce the chance of Salmonella contamination.

Extra about this examine could be found here.

About CPS: The Heart for Produce Security (CPS) is a 501(c)(3), U.S. tax-exempt, charitable group targeted completely on offering the produce trade and authorities with open entry to the actionable data wanted to repeatedly improve the protection of recent produce.

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