Salmonella is a concern in sesame because it can survive for a long time in dry seed, and sesame is often eaten without cooking, on bread, in tahini or in sweets. Even low numbers can make people ill.
It is controlled by keeping seed clean during harvest, drying and processing, adding a validated kill step such as steam sterilisation where needed, and testing each lot. Testing alone cannot make a product safe.
Where contamination comes from
- Field and harvest: soil, animal droppings and birds while seed dries on the ground.
- Market and storage: open storage, rodents and pests.
- Hulling: soaking and washing water that is not clean or not changed often.
- Sun drying: hulled seed spread on open floors exposed to birds and dust.
- After processing: dirty conveyors, bins, bags or hands.
How it is controlled
Good plants work in layers. They keep raw seed and finished product apart, use clean water, dry in closed mechanical dryers, and clean equipment on a schedule. Many add a kill step. Steam sterilisation or pasteurisation can lower Salmonella and total plate count with limited loss of colour and flavour if done well.
A kill step must be validated for sesame and checked on every batch. Ask for the validation and batch records, not only the claim. The process is explained in what steam sterilisation is and when you need it. Ethylene oxide is not an acceptable option for the EU, as covered in what ETO treatment is and why EU buyers reject it.
How testing works
Salmonella is usually tested as present or absent in a set weight, often 25 grams, on several samples from the lot. Because contamination is uneven, more samples give more confidence. A single negative result on a small sample does not prove a lot is clean.
- Agree the number of samples and the sample weight in the contract.
- Use an accredited lab with Salmonella in its scope.
- Test after any kill step, on finished, packed product.
- Add Enterobacteriaceae or E. coli as hygiene indicators.
- Keep counter samples sealed.
What this means for your contract
If you sell into ready-to-eat use, specify Salmonella absent in the agreed test, set limits for plate count, yeast and mould, and state whether the supplier must steam treat. If you will treat the seed yourself, say so, and still set hygiene limits so you receive clean raw material.
Agree in writing what happens if a lot tests positive. Usual options are re-treatment and re-testing, or rejection, with the cost on the supplier.
How Creston & Co handles this
We audit sesame plants for water, drying and hygiene, check kill-step records and draw finished-product samples for Salmonella testing at an NABL-accredited lab. To set up a safe sesame supply, ask for a free sourcing review.