We Set the Odds on the Produce Aisle

We price odds for a living. So when the 2026 cyclospora outbreak blew past 4,000 cases across 31 states with no named source, we treated three decades of outbreaks like a betting market.

We took every documented North American outbreak since 1995. We counted how many people each food sickened. Then we turned each food's share into an implied probability.

One food is the runaway favourite. It is not the one investigators are chasing this summer.

What the Odds Reveal

• Raspberries are the odds-on favourite. A 53 percent chance any documented case is theirs.
• Bagged salad leads the modern era. Behind 30 percent of all cases, and every big outbreak since 2013.
• Four foods tie on frequency. Raspberries, salad, cilantro and basil each caused 4 outbreaks.
• Green onions have no documented outbreak, but we still flag them. Michigan put them on its 2026 advisory list, the same kind of warning cilantro and basil got before either had a confirmed case tied to them.
• Canada is not spared. The 2020 salad outbreak sickened 370 Canadians.
• Only heat is reliable. Washing will not remove the parasite. Cooking kills it.

The Riskiest Foods in the Produce Aisle, Ranked

1 Raspberries

Imported from Guatemala · 4 outbreaks · 2,531 cases

Raspberries are the odds-on favourite, and it is not close. Their implied probability is 53 percent, a near coin flip that any documented case traces back to them.

Almost all of it comes from two events. The 1996 outbreak sickened about 1,465 people across the US and Canada and turned cyclospora into a household worry.

But this bet was settled years ago. Import rules tightened, and no US raspberry outbreak has been recorded since 2000.

2 Bagged salad and lettuce mix

Processed in North America, ingredients often imported · 4 outbreaks · 1,451 cases

Shorten the window to the last decade and this is the clear favourite. Bagged salad carries a 30 percent implied probability and every major outbreak since 2013.

The two biggest were enormous. A 2018 outbreak reached 511 people. A 2020 Fresh Express outbreak reached 701 and crossed into Canada.

It is also the one to watch now. Michigan named lettuce and salad greens a possible source in the 2026 outbreak, though nothing is confirmed.

3 Cilantro

Imported from Mexico · 4 outbreaks · 331 cases

Cilantro ties for the most outbreaks but sits third on the odds, a 7 percent implied probability.

Its outbreaks run smaller and usually start in restaurants. The biggest hit Texas in 2013, with more clusters following in 2014, 2015 and 2018.

Eaten raw and hard to rinse, it never leaves the advisory lists.

4 Vegetable tray

Broccoli, cauliflower and carrots · 1 outbreak · 250 cases

The party tray is the surprise of the ranking, at 5 percent.

It rests on one event. In 2018, Del Monte vegetable trays sickened 250 people and were recalled.

It is the only outbreak tied to a pre-cut tray rather than greens or herbs, and it appears on no advisory list.

5 Basil

Imported · 4 outbreaks · 148 cases

Basil ties for the most outbreaks yet lands fifth, a 3 percent implied probability. It causes trouble often, rarely at scale.

Its biggest was a 2019 outbreak across 11 states, 132 cases. Earlier events in 1999 and 2005 were never fully counted.

6 Snow peas

Imported from Guatemala · 1 outbreak · 96 cases

Snow peas make the board on a single, well-documented event.

In 2004, raw Guatemalan snow peas sickened 96 people at a Pennsylvania facility, the first outbreak ever tied to the vegetable.

None since, but it stays on the advisory list because the import routes have not changed.

7 Green onions

Imported · no documented outbreak · advisory list only

Green onions sit outside the ranking entirely. They are not "safe," they are unranked, and unranked is not the same as cleared.

No North American outbreak with case counts has ever named them, and the CDC leaves them off its own list. That gap could mean genuinely low risk, or it could mean no one has traced a case back to them yet. The data does not tell us which.

We include them because a state advisory is a real signal, even without a confirmed case count behind it. Treat the absence of a track record as unknown, not as a clean bill of health.

Canada Was Not Spared

This is not only an American problem. Canadians buy the same California, Mexican and Central American produce, and the biggest modern outbreak jumped the border.

In 2020, the Public Health Agency of Canada confirmed 370 cases from the Fresh Express salad outbreak. Ontario took the brunt.

Ontario alone out-cased every other province and territory combined. These outbreaks follow the supply chain, not the border.

How to Beat the Odds in the Produce Aisle

Take out two decades-old raspberry outbreaks and one food group owns the modern era. Bagged salads and leafy greens have sickened more North Americans than anything else since 2013, and they are the food under investigation today.

For a shopper, that shrinks a scary parasite to a short list. Favour whole heads over bags, peel what you can, and cook greens and herbs when the recipe allows.

The quieter worry sits upstream. In 2025, the main US early-warning system dropped cyclospora from required tracking, so the next outbreak may surface later than this one did.

The shortest odds in your fridge rarely sit on the food you would suspect.

How We Ran the Numbers

What we measured. Every food ever tied to a documented cyclospora outbreak in North America. We rank them by their share of total reported cases, shown as an implied probability and as odds of 1 in N. That share is the chance a randomly chosen documented case traces to that food. It is not any one person's chance of infection. One food, green onions, has no documented outbreak but appears anyway because it currently sits on a state health advisory list; it is listed separately and unranked, not scored at zero, since an absence of cases is a gap in the record rather than a measured result.

Time period. Outbreaks from 1995 through July 2026.

How we scored it. We summed cases and outbreaks per food from primary reports. We then divided each food's cases by the 4,807 total documented cases to get its implied probability. The odds are one divided by that probability.

What we excluded. The outbreak record comes from US CDC and FDA investigations, the most complete source available. Canadian counts are included where the same outbreak crossed the border. Outbreaks with no compiled case count stay in the outbreak tally but sit out of the case total. The ongoing 2026 outbreak has no confirmed food and is not counted.

Date extracted. 14 July 2026.

Sources

Every outbreak in this study is sourced individually inside the dataset. The key references:

• Full dataset: Cyclospora food vehicle dataset, with a source link for every outbreak
• US Centers for Disease Control and Prevention, Surveillance of Cyclosporiasis
• US Food and Drug Administration, Outbreak Investigation of Cyclospora in Bagged Salads, 2020
• Public Health Agency of Canada, Outbreak of Cyclospora infections linked to salad products, 2020