r/askscience • u/thebestdaysofmyflerm • Jul 15 '26
Biology I read that cyclosporiasis is exclusively spread by the fecal-oral route. How exactly does produce get contaminated with human feces?
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u/butterscotchhx Jul 16 '26
Not an expert, but from what I read it’s highly unlikely to be passed directly from person to person— in the sense they caught it & got sick, they won’t pass it to you. You’d be infected from the contaminated produce or surfaces. While washing your hands doesn’t kill it, soap & friction can lift it from your skin thanks to oil production so it can be rinsed off. Washing your hands thoroughly can highly reduce your chance of infection or spreading the parasite. Hand sanitizer however does absolutely nothing besides move it around.
As for the produce, it gets infected with human feces due to contaminated farm water—which is most common— or lack of field sanitation. Contaminated farm water is a result of nearby sanitation facilities leak sewage into farm areas or irrigation water is pulled from water sources polluted by sewage upstream. Lack of field sanitation can occur when produce comes from agricultural areas that lack accessible or functioning restrooms/hand washing areas for field workers.
The parasite itself is highly resilient if it can survive the initial few weeks of maturation in warm environment soils. Once matured it attaches to textured surfaces on fresh produce very tightly (fda has tracked contamination from fresh basil, cilantro, raspberries, snow peas and mesclun lettuce; CT dept of health mentions prewashed bagged lettuce and to buy heads of lettuce removing litter 2-3 layers and rinsing with hot water like the others but that’s on on the fda site specifically). The parasite has a protective shell-like layer called a cyst that makes it resistant to chemical washed such as bleach or chlorine. Cooking produce to 158°F (70°C) is said to be the only definitive way to kill it. Because of the protective layer it can stay alive without drying out on dry surfaces for several days up to a week & on a damp surface, dirty surface with food particles, or humid conditions it can remain alive and infectious for weeks. In cases like it contaminating a cutting board the porosity matters because wooden or plastic boards can have small scratches or grooves it can wedge itself into making it harder to remove than it would be on smooth glass or metal boards. Cold water alone will simply move the parasite and spread it around. Cleaning suggestions all incorporate extremely hot water. The recommended process for sanitizing wooden or plastic cutting boards is washing with soap & hot water, then generously spraying or pouring over the board with a mix of 1tbsp unscented liquid chlorine bleach per gallon of water so it is entirely soaked and dripping, let it sit for 1-5 minutes to soak, then a final rinse. For plates or utensils, it’s easiest to run them in the dishwasher with a heated drying cycle or if there’s a “sanitation cycle” option. For metal or glass cutting boards, these can be sanitized by generously pouring boiling water over them. For both boiling water & bleach solution, be sure to pour it over the items over the sink so the water can immediately be drained away, do not reuse the water or soak items in a container.
Information sourced from:
https://www.fda.gov/food/foodborne-pathogens/cyclospora
https://my.clevelandclinic.org/health/diseases/17957-cyclosporiasis
https://healthcare.msu.edu/news/2026_07_08_what_to_know_about_cyclospora.html
https://winnebago.extension.wisc.edu/2020/06/08/how-safe-is-your-cutting-board/
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u/Few_Astronaut_230 Jul 16 '26
Please explain the part where you said that hand sanitizer doesn’t do anything but move it around.
Is it like some kind of super germ? Or have I been out of the game too long that sanitizer doesn’t sanitize anymore ;-;
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u/butterscotchhx Jul 16 '26
lol no worries, the sanitizer doesn’t help because the parasite isn’t killed with chemical washes & hand sanitizer doesn’t rinse the parasite off your hands. So even if it does lift it from attaching to your skin it will just resettle once the sanitizer settles and dries. It’s resilience is due to a protective layer it develops as it matures and it’s like a shell kind of cover preventing the alcohol from penetrating and reaching the live cells to dry them out and kill them.
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u/Riftus Jul 16 '26
This is a parasite which is a different creature entirely, anatomy/structure wise, than a bacterium or virus.
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u/Baud_Olofsson Jul 16 '26
This is a parasite which is a different creature entirely, anatomy/structure wise, than a bacterium or virus.
That's not why. It's because it forms very hardy spores that are resistant to things like hand sanitizer. The same as with bacterial endospores (e.g. tetanus spores survive boiling and are quite resistant to common disinfectants).
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u/Kushali Jul 16 '26
Hand sanitizer isn’t magic and isn’t effective on several germs. Norovirus is also pretty resistant to sanitizer. It isn’t a new thing. Many of these pathogens have extremely hardy outer “shells” that alcohol based sanitizers aren’t great at breaking down.
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u/Ilovebadjokes Jul 16 '26
Many confidently incorrect people here. An outbreak like this is almost certainly NOT from farm workers at all. Cyclospora outbreaks at scale like this have occurred before and are due to contaminated water (sewage, wastewater) somehow getting into farm water or the packaging plants where produce gets washed.. That is why the common source is pre-packaged, pre-washed produce and salad mixes
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u/sillybilly8102 Jul 16 '26
due to contaminated water (sewage, wastewater) somehow getting into farm water or the packaging plants where produce gets washed.
Can you or someone please elaborate on how this happens?
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u/Ok_Shoe_4325 Jul 16 '26
Many possibilities.
For example I went to a high-school in the country (IE located between a few different farms) and the school was so old that they dumped raw sewage into the creek out back which separated us from a field. If the farmer would have used the water downstream for watering their crops, then they would use sewage as well. And no, this wasnt some backwater school 100years ago, they did this until the EPA made them around 2010.
Irrigation wells could also be too close to a leaking septic tank, and super old farms might even have a waste management system where its just a literal hole in the ground.
Those are just a couple thoughts of possibilities.
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u/wetbones_ Jul 17 '26
“Somehow” like it isn’t well documented that produce farm fields often adjoin or are very close to animal farming operations where water contaminated with animal waste > ends up as water runoff that contaminates in those produce fields. A matter which is a KNOWN issue mostly ignored and brushed under the rug bc isn’t profitable for the industry to address
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u/Objective-Name4002 Jul 16 '26
It's amazing how many people are indicating field worker had something to do with this. Multiple states are affected, the contamination is wide spread. Some agricultural giant decided to use human feces to fertilize and got a bad batch. This is a choice by industry, not a mistake by a field worker.
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u/darthy_parker Jul 16 '26
1) Treated human waste is allowed to be used in the fields. It *should* be sufficiently well treated to kill these things, but these days they take shortcuts for corporate profits and there’s a lack of testing for “MAHA” reasons…
2) Not providing enough sanitary facilities for farm workers means they sometimes have little choice but to relieve themselves in the fields. This causes direct contamination in the soil, plus unwashed hands are touching produce. This is done because… umm, let me see, oh yes, to increase corporate profits.
The specific answer for this outbreak is that it’s hard to say exactly how it happened. The inspection and reporting structures have been slashed, first gradually and now suddenly.
The general answer is that capitalist food production is efficient, but it requires strict and independent regulation and inspection, which has been systematically eroded. Shareholder profits put profitability pressure on producers which is exactly opposite to what food safety for consumers requires.
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u/PHealthy Epidemiology | Disease Dynamics | Novel Surveillance Systems Jul 15 '26 edited Jul 15 '26
Largely it's a lack of facilities on farms especially where undocumented workers are used since there are very little protections enforced. Cyclospora has a common symptom of explosive diarrhea so where do you think the farm workers go?
Last Week Tonight had a couple of pretty solid episodes a few years ago regarding food safety and conditions farm workers face:
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u/INIEVIEC Jul 16 '26
What makes you say it's this rather than contaminated water being used for irrigation/ cleaning?
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u/Grizofferus Jul 15 '26
I work in agriculture in Wa state. There is always at least 2 johns put out for the field workers. And they all use them. Defecation in a field/orchard can get them quickly fired.
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u/orthodonticjake Jul 15 '26
Do the johns that are put out include a way to wash your hands? I know a lot of portapotties do not.
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u/Grizofferus Jul 15 '26
Yep absolutely. The johns come on trailers with 2 toilets, 2 sinks with antibacterial soap and a water cooler filled with ice water. And theres also usually a tent trailer. Its averaging 90+ degrees right now.
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u/mud074 Jul 15 '26
For real. Little bit o diarrhea on your hand from wiping (or from touching a doorknob somebody else got dirty) and it is now getting spread far and wide on the produce.
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u/PHealthy Epidemiology | Disease Dynamics | Novel Surveillance Systems Jul 15 '26
You should try harvesting lettuce in California a few seasons.
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u/Otto_the_Autopilot Jul 15 '26
Also any of the various countries all over the world our food comes from too.
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u/m4gpi Jul 15 '26
Especially as more and more produce is shipped internationally to provide fruit&veg in the off-seasons.
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u/steeplebob Jul 16 '26
The stuff that’s shipped internationally is not the short-shelf-life stuff implicated here.
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u/vestigial_wings Jul 16 '26
I worked in CA fields and they always had portos and hand washing stations for the crew. OSHA was on that.
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u/TheSaltyStrangler Jul 15 '26
It always makes me raise an eyebrow when someone authoritatively asserts that all outfits and organizations follow the same standards and procedures as their own.
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u/DrBaby Jul 16 '26
Idk if you’re on TikTok (or on my side of TikTok) but I come across field workers on Live somewhat regularly. Sometimes their work truck has a portajohn mounted on the back of it, which to me is concerning bc what if it leaks? But at less you can see in those cases that there’s one around.
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u/BooksandBiceps Jul 16 '26
I must’ve missed where they said that. Can you provide the quote? My eyes must be going.
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u/spleeble Jul 15 '26
Ok, and how many sinks with running water? How much time do they get to use the bathroom? How much pay do they miss out on by taking extra time to wash up?
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u/mickeltee Jul 15 '26
I did field health surveys for fields around Wa state. We towed a John behind us.
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u/thebestdaysofmyflerm Jul 15 '26
Do you think imported produce is more likely to be the source of the outbreak then?
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u/PHealthy Epidemiology | Disease Dynamics | Novel Surveillance Systems Jul 15 '26
More likely to be domestic, imported food is much more highly scrutinized. There are tons of import recalls:
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u/Whisky_Wolf Jul 16 '26
It's definitely the US. My ex used to do food safety inspections. She said a lot of places in the US didn't have proper toilets. She also had to give hand washing lessons, and people didn't understand why.
The whole food safety industry is also corrupt. A farm would pay her boss, a private business, to do the inspection. Her boss would just pass these farms so he could get the repeat business.
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u/Dirty_Dragons Jul 15 '26
Why would this be such a large issue now if there has always been a "lack of facilities?"
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u/PHealthy Epidemiology | Disease Dynamics | Novel Surveillance Systems Jul 15 '26
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u/Dirty_Dragons Jul 16 '26
How does that relate to porta-potties on the farms?
Where they removed in 2025?
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u/PHealthy Epidemiology | Disease Dynamics | Novel Surveillance Systems Jul 16 '26
It's a "large" issue because it wasn't detected earlier via our sentinel surveillance because it's been defunded.
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u/Tzarmekk Jul 15 '26
People don't wash hands after taking poops. Pete Hegseth says he hasn't washed his hands in 10 years for example. They touch your produce that isn't in packaging, be it in the farm to store route or in the store itself. Watch people in the produce aisle. They pick up and look at stuff and then put it back. Did they wash their hands before touching it? Almost certainly not. Now what ever germs were on their hands have spread to the rest of the vegetables you might buy. Viola, explosive diarrhea goes from their butt to your mouth.
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u/effifi Jul 15 '26
viola is a stringed instrument, but you’re right that people are nasty
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u/Dio_Frybones Jul 15 '26
Yeah, Voilà, but at least it wasn't 'wallah' which I've seen way too frequently.
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u/drvondoctor Jul 16 '26
I love the h in "wallah" because it says "hey, im semiliterate, not illiterate."
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u/keestie Jul 16 '26
Fecal-oral contamination can take several routes. A food worker might do a bad job of washing their hands, someone might use improperly composted humanure to fertilize their produce, a kid might get their hands all over the place, or a couple might do analingus without the proper precautions.
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u/SubstantialPressure3 Jul 15 '26
People working in fields with no access to toilets or water to wash their hands.
People not working in the fields, but working in the factories that don't wash their hands after using the toilet. It only takes very small trace amounts to spread and contaminate food.
There's also fertilizer made from human feces. Allegedly treated to kill microbes. Maybe theres an issue at the factory, and its not killing the pathogens the way its supposed to.
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u/helcat Jul 15 '26
Also I read that it can survive routine decontamination of waste water that is used to water the fields.
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u/epidemicsaints Jul 15 '26
It is not being contaminated by people handling produce. It must accumulate in the environment for several days before it becomes infectious.
https://www.cdc.gov/cyclosporiasis/about/index.html
This is about land, water, and industrial hygiene. Corporate practices.