Publisher’s Platform: What did we learn – or not – from the 2020 onion outbreak
The last few weeks have sounded remarkably familiar to Spring 2020 when we faced a nationwide (and Canada) Salmonella outbreak linked to California grown onions. We are now facing a similar outbreak – smaller at this point (more than 650 vs. more than 1,600 sickened) – but it will be interesting to see if the root cause of the outbreak tracks as the below 2020 case.
Here is what the FDA said in May 2020:
The U.S. Food and Drug Administration (FDA) has released a report on its investigation of the Salmonella Newport outbreak that caused more than 1,600 reported illnesses in the U.S. and Canada between June and October 2020. The FDA worked with the U.S. Centers for Disease Control and Prevention (CDC), state partners, and Canadian officials (Public Health Agency of Canada and Canadian Food Inspection Agency) to investigate the outbreak, which was linked through epidemiology and traceback to whole red onions supplied by Thomson International Inc., headquartered in Bakersfield (Southern San Joaquin Valley) with additional operations in Holtville (Imperial Valley), California.
The outbreak is the largest Salmonella foodborne illness outbreak in over a decade. The report released today includes an overview of the traceback investigation, subsequent on-site interviews, visual observations of the growing fields, and environmental sampling, and various factors that potentially contributed to the contamination of red onions with Salmonella.
Although a conclusive root cause could not be identified, several potential contributing factors to the 2020 Salmonella outbreak linked to red onions were identified. These include:
- potentially contaminated sources of irrigation water;
- sheep grazing on adjacent land;
- signs of animal intrusion, including scat (fecal droppings), and large flocks of birds that may spread contamination; and
- food contact surfaces that had not been inspected, maintained, or cleaned as frequently as necessary to protect against the contamination of produce.
In sampling conducted in Holtville, CA, the FDA found Salmonella Newport in 10 water (irrigation, seepage, and drainage) and one sediment subsamples. However, the whole genome sequencing of these samples did not match the outbreak strain.
Although a conclusive root cause could not be identified, several potential contributing factors to the 2020 red onion outbreak were identified, including a leading hypothesis that contaminated irrigation water used in a growing field in Holtville, CA may have led to contamination of the onions.
In light of this report, the FDA encourages all farms to:
- assess growing operations to ensure implementation of appropriate science and risk-based preventive measures, including applicable provisions of the FDA Food Safety Modernization Act (FSMA) Produce Safety Rule and good agricultural practices;
- implement industry-led root-cause analyses to determine how the contamination likely occurred when pathogens are identified through pre-harvest or post-harvest testing of produce, or microbiological surveys;
- be aware of and consider the risks that may be posed by adjacent and nearby land uses, especially as it relates to the presence of livestock and the interface between farmland, rangeland, irrigation water, and other agricultural areas;
- consider additional tools such as pre-harvest and/or post-harvest sampling and testing of products to help inform the risk assessment and clarify the need for specific prevention measures; and
- improve traceability by increasing digitization, interoperability and standardization of traceability records; and
- follow good agricultural practices to maintain and protect the quality of water sources.
Although the present outbreak appears to be onions grown in Mexico provided nationwide in the United States, and to Canada, though various suppliers in the United States, it will me interesting of we are just seeing history repeat itself.
It also will be interesting if the slow roll out of the FDA “water rule” had an impact in both of the outbreaks?
Here are the compliance dates:
“Larger farms are now required to comply with the agricultural water requirements by January 26, 2022, while small farms have until January 26, 2023 and very small farms until January 26, 2024. This rule does not change the compliance dates for sprout operations.”
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