The usual question is how to wash greens properly. It is the wrong place to start, because washing is the last and weakest step in the chain. What decides your actual risk is which of three products you are holding, and where in its life the contamination happened.
Sprouts, microgreens and leafy greens get lumped together as “fresh greens.” They fail in three different ways, and the difference is worth knowing before you buy seed or a bag of salad.
Three products, three different failure modes
| Product | Where contamination comes from | Why it multiplies | Your main lever |
|---|---|---|---|
| Sprouts | The seed, usually contaminated in the field a season earlier | Several days in warm water in a closed jar | Seed sourcing, or skipping raw sprouts |
| Microgreens | The seed, and the substrate if it is reused | Much less: the crop is cut above the root in days | Seed sourcing and cutting height |
| Leafy greens | Irrigation water, wildlife, and shared processing equipment | Cross contamination during cutting and bagging | Cooking, and following recalls |
A jar of sprouts is the only one of the three where you are deliberately running the conditions a microbiology lab would use to grow bacteria: warm, wet, dark, several days, no competition. That is why sprouts appear in the outbreak record far out of proportion to how much of them people eat.
The comparison goes deeper than this table. The FDA defines a sprout by how it is harvested rather than by species, and sprout producers carry batch testing obligations that no other fresh produce does: sprouts vs microgreens, and why the outbreak risk is not the same.
Washing does not undo contamination
This is the part that surprises people, and it has two separate reasons behind it.
For parasites on leaf surfaces, the organism holds on. Cyclospora oocysts stick to the leaf and survive ordinary rinsing, which is exactly what the record-setting iceberg lettuce outbreak demonstrated: 12,883 illnesses across 21 states, 570 hospitalizations and two deaths. The full breakdown is in why washing your lettuce would not have helped. Countertop produce washers do not close that gap either, and the reasoning is short enough to check yourself in the piece on whether the Pure Pod works against Cyclospora.
What a processing line actually does to the water, and why none of it transfers to a kitchen, is covered separately in chlorine, PAA and ozone: the doses and their limits. The same reasoning explains what a “triple washed” claim really promises and why a hydrogen peroxide soak falls short of what people expect from it.
The devices sold as an answer to the same problem are each covered on their own: ozone produce washers, where a fruit and vegetable washer turned out to be the strongest ozone source of seventeen appliances tested; UV-C wands and boxes, where line of sight decides everything; ultrasonic cleaners, where the physics works and the appliance does not. And one device that approaches the problem from the other end: countertop hydroponic gardens, where the first documented outbreak from indoor hydroponic greens showed that indoors is not the same as sterile.
For bacteria on sprouts, the problem is location. When a seed carries Salmonella or E. coli and then germinates, the bacteria multiply throughout the sprouting mass rather than sitting on an outer surface you can reach. Rinsing the finished sprouts moves water past the outside of something that is contaminated all the way through.
Washing is still worth doing. It removes soil, some surface bacteria and pesticide residue. Some cells stay out of reach of water entirely, because they sit inside the leaf tissue. It is a small reduction in risk, and treating it as the main defense is what gets people hurt.
What washing does and does not achieve is broken down by method: the real vinegar numbers, what a baking soda soak removes, and whether the sprays beat tap water. Why bacteria already attached to a leaf rinse off so poorly is explained in biofilms on produce. How greens pick up contamination in the kitchen itself, from the sink to the cutting board, is covered in kitchen cross-contamination. Why melons and avocados need washing even though nobody eats the skin is covered in washing bananas, avocados and melons. Raw chicken and the splashes it leaves around the sink are the subject of should you wash chicken.
For sprouts and microgreens, the seed is the whole game
Contamination almost never starts in your kitchen. It starts in a seed field, often a year before the seed reaches you, through irrigation water or animal contact. One contaminated lot then gets split among many buyers, which is how a single seed lot produces illnesses in a dozen states at once. The mechanism is laid out in how one contaminated seed lot becomes a 15-state outbreak.
Two practical consequences follow.
- Buy seed sold for sprouting or microgreens, with a lot number on the package. Seed sold for planting in soil is grown, cleaned and stored under different rules, and nobody expects you to eat it raw a week later. The lot number is what makes you reachable if that batch is ever recalled.
- A recall can arrive late or not at all. The FDA can request a recall, and a company can decline. That is not hypothetical: it happened during the 2026 alfalfa investigation, described in what happens when a company refuses an FDA recall request.
A tray beats a jar
If you grow at home, this single choice changes your exposure more than anything else you can do.
In a jar you eat the entire organism: seed hull, root, stem and leaf, after it has spent several days soaking. In a tray you cut above the root, and the seed hulls and root mat stay behind in the substrate. The seed can carry exactly the same contamination in both cases, but the tray leaves most of it in the tray and skips the warm standing water entirely.
That lowers the risk without removing it. Use fresh substrate rather than reusing it, drain and discard soaking water instead of reusing it, and keep cutting height above the root mat rather than scraping the surface.
Who should skip raw sprouts entirely
For most healthy adults, raw sprouts are a small risk taken knowingly. For four groups the advice is different, because the same dose of the same organism produces a much worse outcome:
- Adults over 65
- Children under 5
- Pregnant women
- Anyone with a weakened immune system, including people on chemotherapy or immunosuppressants
Cooking resolves it. Sprouts cooked through carry essentially none of this risk, which is why the same mung bean sprouts that worry food safety agencies raw are unremarkable in a stir fry.
How to read an outbreak announcement
When a recall or investigation hits the news, three things are worth checking before deciding whether it touches you.
- Is a product actually named? Most open investigations have no identified food at all. In the FDA’s own table, a visible case number usually means the agency has not yet found the source, and a named product means the traceback landed. We keep a dated monthly snapshot in open FDA outbreak investigations.
- Is the product still on shelves? Fresh produce is often gone before its own recall notice arrives. By the time romaine was identified in one 2026 investigation, the product was already past shelf life, which makes the recall a record-keeping act rather than a consumer action.
- Does “investigation active” mean people are still getting sick? Often not. Agencies keep files open after an outbreak ends, because the point of the remaining work is preventing the next one.
The 2026 alfalfa case is a compact example of all three at once: two pathogens in one outbreak, 55 illnesses across 15 states, and a recall that kept widening. It is written up in the alfalfa sprout outbreak. For an outbreak where investigators reached a specific field and found no broken rule at all, see our account of the 2006 spinach outbreak.
Crop by crop
Twelve crops in our catalog are commonly grown as raw sprouts, and each card carries its own safety note alongside the growing instructions: alfalfa, clover, mung bean, radish, broccoli, lentil, fenugreek, chickpea, mustard, sunflower, pea and wheatgrass.
The rest of the catalog, including the crops that are only ever grown in trays, is in the full microgreens directory. For a processed form of the same crops, see Salmonella in dried greens powders.
Bottom line
- Risk is set by the product category, not by how carefully you rinse.
- For sprouts and microgreens, seed sourcing is the main lever, and a lot number on the package is what keeps you reachable in a recall.
- A tray with cutting above the root is meaningfully safer than a jar.
- Four groups should skip raw sprouts entirely, and cooking removes the problem for everyone.
- For leafy greens, washing helps a little, following recalls helps more, and cooking settles it.