Salmonella Outbreak Linked to Onions—a Post-mortem


Reported cases: 1,642
Hospitalizations:
246
States affected:
48
Provinces affected:
7
Infectious agent: Salmonella Newport
Probable source: Red onions produced and packed by Thomson International, Inc. of Bakersfield, CA


Two months after the US Centers for Disease Control and Prevention (CDC) and the Public Health Agency of Canada (PHAC) declared this outbreak over, its root cause remains a mystery.

The US Food and Drug Administration (FDA) has plowed through more than 2,000 samples, testing finished products, swab and environmental samples from Thomson’s packing facility, and environmental samples from the vicinity of the fields where the onions were grown.

FDA labs recovered eleven different Salmonella serotypes from the various environmental samples, according to information obtained by eFoodAlert in response to a Freedom of Information Act request.

Although Salmonella Newport was found in two samples described as soil/sediment, neither sample yielded the outbreak strain recovered from patients.

Not one of the onions tested in FDA labs were Salmonella-positive.

Not one of the swab samples obtained from inside the Thomson packing facility were Salmonella-positive.

But this is not the whole story. To understand FDA’s findings, it’s important to know more about onions.

The onion

Onions can be grown from seeds, seedlings, or sets (immature onion bulbs). The crop is ready for harvest when at least one-half of the leaves are dead.

In order to ensure an adequate storage life, the onions must be left in the field to “cure” for at least 12–24 hours. This allows the outer skin to dry. Curing is complete when the neck of the onion (the top of the bulb) is dry and tight.

After curing, the onions are “topped” above the neck to remove the leaves, after which they are ready for eating or for extended storage.

Onions are closely related to garlic and, like garlic, onions produce certain essential oils that possess anti-bacterial properties. Although Salmonella can survive on onions, these essential oils complicate the process of detecting the bacteria.

Thomson’s onion operations

Onions are onions, whether grown in a small backyard or in a large commercial field. The same principles apply. The differences are those of scale.

Thomson’s onions are grown from seeds in two different parts of California. The company uses fields both near Bakersfield, where its packing house is located, and just outside Holtville, in California’s Imperial Valley, approximately 330 miles to the south.

When the onion crop is ready for harvest, Thomson’s crews use specialized equipment to dig beneath the bulbs and cut them out of the ground. The onions are left in the field to cure.

Once the onions have cured, a crew of farm laborers works its way through the field, trimming off the tops and bottoms of the onions, culling and discarding damaged onions, and placing the trimmed onions into buckets.

Culled onions and the trimmed-off tops and bottoms are left in the field to be plowed back into the soil when it is prepared for the next crop.

The full buckets are poured into burlap bags, which are left in the field for additional curing.

Once curing is complete, the onions are either shipped in bulk directly to customers or are transported to Thomson’s Bakersfield packing facility, where they are brushed clean and packed for distribution.

What FDA did not find

  • No “egregious” conditions or violations of the Produce Safety Rule
  • No direct evidence of the outbreak strain in bagged onions
  • No direct evidence of the outbreak strain in any environmental samples either at the packing facility or in and around the fields

What FDA found in Bakersfield

  • Cats in and near the onion packing lines
  • Pigeons flying or roosting inside the packing house
  • Apparent bird droppings on and near the onion packing line
  • A thick build-up of dirt and soil on the packing line even after the most recent cleaning/sanitizing activity
  • Rough, dirty weld points on the packing line
  • Inadequate documentation of cleaning/sanitizing activity
  • Swallow nests overhead within a few feet of an onion-packing line
  • Inconsistent cleaning/sanitation Standard Operating Procedures documentation
  • Inconsistent bacteriological testing of agricultural water for coliforms and E. coli.
  • Salmonella in animal scat, drain sediment, and environmental swab sample and on a water filter

What FDA found in Holtville

  • Worn and uneven areas on field packing equipment that could harbor bacteria
  • Indications of bird activity around the fields and equipment
  • Flock of birds (ibis) in field undergoing flood irrigation adjacent to field where onions had been grown
  • Salmonella, including Salmonella Newport, in several soil/sediment samples

And then there’s the water…

Information received under a Freedom of Information Act request is often heavily redacted, as anyone knows who watches The Rachel Maddow Show on MSNBC. This is what FDA’s investigation report had to say about the source of irrigation water used on the onion fields.

It would appear that irrigation water was drawn from a different source than was usual on at least one occasion. The details and date(s) on which this took place were redacted from the report, as was the diagram showing the flow of water from the source to the fields.

Why does this matter?

Irrigation water polluted by runoff from cattle feedlots has been linked to contaminated produce grown in the Salinas and Imperial Valleys in the past. A quick look at a Google map for the areas around Bakersfield and Holtville reveals the presence of feedlots in both vicinities.

The bottom line

As soon as Thomson onions were identified by CDC and FDA as the probable source of the Salmonella Newport outbreak, the company shut down its harvesting and packing operations.

By the time FDA investigators arrived on the scene, there were no field or packing activities for them to observe. The investigators were able to carry out extensive sampling of the equipment surfaces, the environment, and the stored onions, but were unable see either the harvest or packing operations in action.

Although neither FDA nor the Canadian Food Inspection Agency were able to find the outbreak strain in any of the onion samples, all of the epidemiological evidence from both the CDC and the PHAC points to Thomson’s red onions as the source of the outbreak,

The presence of multiple Salmonella-positive environmental samples lends weight to this conclusion, although the actual source of the contamination likely will never be known.

Thomson Onion Salmonella Outbreak: Is CDC Missing in Action?


On July 21, 2020, the US Centers for Disease Control and Prevention (CDC) informed the public of an outbreak of Salmonella Newport infections.

On July 24th, the Public Health Agency of Canada (PHAC) informed the public of an outbreak of Salmonella Newport infections apparently caused by the same outbreak strain as CDC was finding in the United States.

At the time of the initial reports, neither agency had determined the source of the outbreak.

On July 30th, PHAC updated its outbreak advisory, informing Canadians that the outbreak was linked to consumtion of red onions imported from the United States. That same day, the Canadian Food Inspection Agency (CFIA) posted a recall notice for red onions imported by Sysco in Western Canada.

Using the Canadian data as its starting point, on July 31st, the US Food and Drug Administration (FDA) and CDC announced that the US outbreak was linked to consumption of red onions produced by Thomson International, Inc. of Bakersfield, California.

Thomson International is a family-owned business, incorporated in California.

On August 1st, Thomson recalled its entire harvest of red, yellow, white, and sweet yellow onions from the 2020 growing season – approximately 18,750 tons of onions. The onions were distributed across the United States and exported to Canada.

CDC issued status updates of the size and scope of the US outbreak on August 3rd, August 7th, August 18th and September 1st, and has not been heard from since.

PHAC issued status updates of the size and scope of the Canadian outbreak on August 2nd, August 7th, August 14th, August 21st, August 31st and September 14th.

By August 7th, FDA had initiated its on-site investigation of Thomson’s Bakersfield facility, looking for the source of the Salmonella Newport contamination. By August 11th, FDA personnel had submitted 370 samples to the agency’s lab for Salmonella testing, including 278 swab samples, 82 onion samples, and 10 miscellaneous environmental samples, according to information obtained by eFoodAlert in response to a Freedom of Information Act request.

Not a single sample contained Salmonella.

The FDA investigation is still in progress. However, with the growing season complete and the packing plant idle, the chances of finding the source of the Salmonella Newport diminish day by day.

As of the last report from CDC, 1012 individuals in 47 states have been infected with Salmonella Newport as a result of having consumed contaminated onions. Only Louisiana, Oklahoma and Vermont have not reported any outbreak cases. Although there have been no deaths associated with this outbreak, 136 (more than 13%) of the victims have required a hospital stay.

In Canada, there have been 506 confirmed cases of Salmonella Newport in seven provinces, and 71 people (14%) have been hospitalized.

Canada v. USA – A Performance Comparison

Why was CDC unable to determine the link between red onions and the Salmonella Newport outbreak until after PHAC had made the connection?

Why has CDC not provided an update to its outbreak status report in three weeks?

Why does Canada appear to have been much harder hit by this outbreak than the United States – 13.7 cases per million Canadians versus only 3.1 per million Americans? Is this due to some quirk of distribution, or have PHAC and its provincial partners done a better job of reporting than CDC and the various state health agencies?

Has the Covid-19 pandemic hit CDC so hard that it no longer has the resources to follow-up on illness outbreaks elsewhere?

 

IF CDC IS MISSING IN ACTION, WHAT DOES THIS MEAN FOR THE HEALTH AND SAFETY OF THE US POPULATION?

 

 

Contaminated Peaches from USA Cause Salmonella Outbreak in Canada


Thirty-three Canadians in Ontario (22 cases) and Quebec (11 cases) have become infected with Salmonella Enteritidis after consuming peaches imported from the USA, according to a report released this morning by the Public Health Agency of Canada (PHAC).

Three of the outbreak victims have been hospitalized.

Those infected with the outbreak strain of Salmonella Enteritidis range in age between 0 and 91 years, and 55% of the victims are female.

The outbreak is linked to peaches supplied by Prima Wawona, a California-based company, which has recalled a series of products from the marketplace.

Prima Wawona peaches have also been blamed for an outbreak of Salmonella Enteritidis in the USA, which had sickened 68 individuals in 9 US states as of August 21st, according to the US Centers for Disease Control and Prevention.

On August 22nd, the Canadian Food Inspection Agency (CFIA) issued a Consumer Advisory alerting Canadians to the presence of the recalled peaches in the country and warning that PHAC had identified some illnesses linked to their consumption.

Canadian consumers should avoid purchasing, serving or eating any of the following peaches, or any other food products containing these peaches.

  • Harvest Sweet Sweet 2 Eat Prima Sweet Value Wawona Yellow Peaches; PLU 4037, PLU 4038 PLU 4044,
  • Harvest Sweet Sweet 2 Eat Prima Sweet Value Wawona White Peaches; PLU 4401
  • Sweet 2 Eat Sweet O Organic Yellow Peaches; PLU 94037, PLU 94038, PLU 94044
  • Sweet 2 Eat Organic White Peaches; PLU 94401
  • Wawona Peaches; 907g / 2 lb; UPC 0 33383 32200 1
  • Wegmans Peaches; 907g / 2 lb; UPC 0 77890 49048 8
  • Extrafresh Peaches; 907g / 2 lb; 0 33383 02071 6; Codes CPO3148, CPO3164, CPO3163, CPO3186, CPO3207, CPO3213, CPO3228, CPO3265, CPO3281, CPO3302, CPO3328, CPO3354, MPO0500, MPO0503, MPO0524, MPO0671, MPO0678, MPO0689, MPO0693, MPO0703, MPO0716, MPO0725, MPO0730, MPO0767, MPO0795

Peaches imported in bulk may have been sold loose or in bulk, with or without a brand name. These peaches may have been repackaged into a variety of formats.

Except for the Extrafresh Peaches, the recall encompasses all products sold from June 1, 2020 forward.

What Consumers Need to Know

  • Do not purchase or consume any peaches listed above. If you are in doubt as to the origin of peaches which you have already purchased, throw them away and disinfect the bin in which they were stored.
  • Some of the peaches may have been supplied to restaurants, hotels, bakeries or various food service establishments, including hospitals and nursing homes and may have been used in salads, desserts or baked goods. It would be prudent to avoid all of these items, unless you can be certain they were produced using peaches not included in this Advisory.
  • If you are suffering from symptoms of salmonellosis, including low-grade fever, stomach cramps, diarrhea, and/or vomiting, consult your healthcare professional. Be prepared to provide information on the food items you consumed during the week before beginning to experience your symptoms

This is the third Canadian foodborne disease outbreak since the beginning of July, all of them linked to consumption of produce imported from the USA. Local produce is readily available during the summer months. Consider supporting your local producers instead of buying imported produce.