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.

Recalls and Alerts: October 8 – 10, 2020

Here is today’s list of food safety recalls, product withdrawals, allergy alerts and miscellaneous compliance issues. The live links will take you directly to the official recall notices and company news releases that contain detailed information for each recall and alert.

If you would like to receive automatic email alerts for all new articles posted on eFoodAlert, please submit your request using the sidebar link.

United States

OUTBREAK ALERT (Minnesota): Minnesota Department of Health (MDH) reports 9 cases of Salmonella Paratyphi B infections in the state linked to the NéktƏr Juice Bar in Woodbury, MN. Two people have been hospitalized. Health officials say anyone who is experiencing severe symptoms of salmonellosis after consuming menu items from NéktƏr should talk to their health care provider.

OUTBREAK ALERT FINAL UPDATE: CDC reports a total of 1,127 confirmed cases of Salmonella Newport infections and 167 hospitalizations in 48 states. The illness outbreak was linked to red onions from Thomson International, Inc., of Bakersfield, California. FDA, CDC and state investigators have found various Salmonella strains in multiple Thomson International Inc. locations and surrounding areas. The root cause investigation is on-going.

Public Health Alert: FSIS issuesa public health alert for ready-to-eat (RTE) meat and poultry bowl products, produced by Taylor Farms in Dallas, Texas on Oct 5 and Oct 6, 2020, due to concerns that the products may be contaminated with extraneous material, specifically glass. No recall was requested, as it is believed that the products are no longer available for consumers to purchase. Please refer to the Alert for a complete list of affected products.

Allergy Alert: B&G Foods recalls Back to Nature Organic Rosemary & Olive Oil Stoneground Wheat Crackers (6 oz; Best by APR 25 2021; UPC 8-19898-01015-8) due to undeclared peanut.

Pet Food Safety Recall Update: Sunshine Mills, Inc. recalls certain Champ®, Field Trial®, Good Dog, Hunter’s Special®, Old Glory®, Paws Happy Life®, Pet Expert, Principle, Retriever®, River Bend, Sportsman’s Pride®, Sprout®, Thrifty®, Top Runner® or Whiskers & Tails products that were made with corn that contained Aflatoxin at levels above FDA’s action levels. This is an expansion of an earlier recall. Please refer to the FDA Alert for a consolidated list of recalled products.

Canada

Food Safety Recall: Hilly Acres Farm recalls eggs with best before dates from September 2, 2020 to October 31, 2020 inclusively where the lot code contains “38” or “N38” or where there is no lot code on the package due to possible Salmonella contamination. Please refer to the recall notice for a complete list of affected products, which were distributed in Nova Scotia and Newfoundland and Labrador. The recall was triggered by the company’s own test results.

Food Safety Recall: Au Palais sucré recalls certain soups and sauces that were prepared, packaged or stored under conditions that could render the items unsafe for human consumption. Please refer to the recall notice for a complete list of affected products.

Food Safety Recall: Griffith Foods Ltd. recalls various Griffith Foods brand seasonings and sauces due to Salmonella contamination. Please refer to the recall notice for a complete list of affected products.

Europe

Allergy Alert (Belgium): Colruyt recalls Boni Selection houmous mangue-coco / mango-coconut hummus (150g; Use by 27/10/2020) due to undeclared sesame.

Allergy Alert (France): Lidl recalls several batch codes of Select & Go brand Salade Buddha Bowl Chèvre / goat cheese salad bowl due to undeclared peanut. Please refer to the recall notice for a complete list of affected batch codes.

Allergy Alert Update (Ireland): Industry recalls Dunkin Boston Kreme Donuts (148g 2-pack; All date codes) due to undeclared egg, gluten (wheat), milk, nuts (almond, hazelnut, pistachio nut), and soya in the English labeling.

Allergy Alert (Luxembourg): Colruyt recalls Boni Selection houmous mangue-coco / mango-coconut hummus (150g; Use by 27/10/2020) due to undeclared sesame.

Allergy Alert (Netherlands): Lidl recalls Ons & Pond dropstaafjes / licorice bars (250g; Expiry date 11-02-2022) due to undeclared wheat (glluten).

Allergy Alert (UK – Northern Ireland specific): North South Retail recalls Dunkin Boston Kreme Donuts (148g 2-pack; All date codes) due to undeclared egg, gluten (wheat), milk, nuts (almond, hazelnut, pistachio nut), and soya in the English labeling.

Food Safety Recall (Belgium): La Ferme Fromagère de Chertin recalls Boulette de Chertin fromage au lait cru écrémé de vache / skimmed raw cow’s milk cheese (200g; Best before 10.10.2020, 15.10.2020, 18.10.2020, 20.10.2020, 01.11.2020, 05.11.2020, 10.11.2020) due to Listeria monocytogenes contamination.

Food Safety Recall (Denmark): Amanda Seafoods A/S recalls Bornholms Hummersuppe / Lobster soup (375g; Production date 03-04-2020; Time stamps 1432 to 1637) due to inadequate heat processing.

Food Safety Recall (France): La Brasserie Licorne recalls Jalisco brand Bière saveur tequila RED / tequila-flavoured beer (3 x 33 cl; Expiry date 17/10/21) due to foreign matter (glass fragments) contamination.

Food Safety Recall (Germany): Firma Dr. Schröter Feinkost GmbH recalls Mühlenhof Delikatess Kräuterfleischsalat / delicatessen herb meat salad (Best before 24.10.2020) due to foreign matter (transparent pieces of plastic) contamination.

Food Safety Recall (Germany): Teaflower Marktstand Shuster Viktualienmarkt recalls Teaflower Teufelskralle gemahlen / ground devil’s claw (200g; Expiry date 10.22) due to Salmonella contamination.

Food Safety Recall (Italy): CASEIFICIO CEIRANO – VILLOSIO SRL recalls CASEIFICIO CEIRANO – VILLOSIO SRL brand RASCHERA DOP cheese (Lot code 06-06-2020; Best before 09-11-2020) due to Salmonella Brandenburg contamination.

Asia, Africa and the Pacific Islands

Pet Food Safety Recall Update: Sunshine Mills, Inc. recalls certain Champ®, Field Trial®, Good Dog, Hunter’s Special®, Old Glory®, Paws Happy Life®, Pet Expert, Principle, Retriever®, River Bend, Sportsman’s Pride®, Sprout®, Thrifty®, Top Runner® or Whiskers & Tails products that were made with corn that contained Aflatoxin at levels above FDA’s action levels. This is an expansion of an earlier recall. Please refer to the FDA Alert for a consolidated list of recalled products. Some of the recalled products were supplied to a distributor in Jordan.

Australia and New Zealand

Allergy Alert (New Zealand): Bin Inn Kapiti recalls Air Popped Buckwheat Seeds (Bullk bins; All batches and dates sold up to and including 9 October 2020) due to undeclared gluten.

Food Safety Recall (New Zealand): Foodstuffs Own Brands Ltd recalls Value Brand Viva Italia Chopped Tomatoes in Juice (400g cans; Batch codes SMS1 J213, TTA1 J214, TTA1 J215, TTA1 J217) due to foreign matter (stones) contamination.

Latin America and the Caribbean

Pet Food Safety Recall Update: Sunshine Mills, Inc. recalls certain Champ®, Field Trial®, Good Dog, Hunter’s Special®, Old Glory®, Paws Happy Life®, Pet Expert, Principle, Retriever®, River Bend, Sportsman’s Pride®, Sprout®, Thrifty®, Top Runner® or Whiskers & Tails products that were made with corn that contained Aflatoxin at levels above FDA’s action levels. This is an expansion of an earlier recall. Please refer to the FDA Alert for a consolidated list of recalled products. Some of the recalled products were supplied to a distributor in Colombia.

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?