Salmonella in sesame seeds and in dehydrated onion is controlled with a validated kill step, such as steam treatment, followed by clean handling and lot testing. Drying alone does not kill Salmonella. These are low-moisture foods, and the bacteria can survive in them for long periods even though they cannot grow.
Most buyers specify Salmonella as absent in a stated sample weight, commonly 25 g, tested on a number of samples from the lot. Confirm the exact criterion with your regulator and your own food safety plan.
Why sesame carries a risk
Sesame is grown, harvested and dried in open conditions, so it can pick up contamination from soil, birds, animals and water. Hulled sesame has had its protective outer coat removed, and cleaning and hulling involve water and wet processing that can spread bacteria if not controlled.
Read why Salmonella is a concern in sesame for the pathways. For the buyer the point is simple: look for a kill step that has been validated, not just a promise of clean seed.
Why dehydrated onion carries a risk
Onion is grown in soil and handled in the field. Washing, slicing and drying lower the water but do not reliably destroy bacteria. Contamination can also come after drying, from dust, equipment, packing and storage.
That is why a plant needs both a kill step and hygiene that protects the product afterwards. See why Salmonella appears in dehydrated onion.
Control steps to ask about
- A validated treatment, such as steam sterilisation, with records of time and temperature for each batch.
- Separation of raw and treated product, with different areas, equipment and staff movements.
- Environmental monitoring in the plant, including swabs on floors and equipment.
- Clean, dry, sealed storage and packing, with pest control.
- A written food safety plan and, if your market expects it, a recognised certification scheme. Check the scope and date of the certificate.
Test plans and microbial limits for spices
Microbial limits for spices usually cover Salmonella, the total plate count, yeasts and moulds, and indicator organisms such as E. coli. The limits are set in the contract or by your market's rules, so confirm them before ordering.
Test each lot, not each season. A negative result on a small sample does not prove the lot is free, but it reduces risk, particularly when combined with process records. Ask whether the plant also tests its own treated product, and compare its results with an independent lab. For more on microbial limits in spices, see ethylene oxide and pesticide residue testing, since treatments and residues interact.
Questions that expose a weak process
- Where is the kill step in the process, and is it applied to every lot or only on request?
- What temperature and time does the treatment use, and who validated it?
- What stops treated product from touching raw product afterwards?
- How many samples per lot does the plant test, and how big is each sample?
- What did the plant do the last time a result was positive?
A note on responsibility
The importer is legally responsible for food safety in most markets. Confirm the limits and the required controls with your food safety authority or consultant, and do not rely only on the supplier's statement.
Next step
We check the plant's treatment records, take samples from the lot and send them to an independent lab. To arrange this for your product, book a free sourcing review.