Microbiological Quality

In short

Microbiological specifications control Salmonella, Enterobacteriaceae, moulds and yeasts, protecting animal health, plant hygiene and — for several species — the human food chain.

Measured as: Salmonella absence in 25 g (ISO 6579); Enterobacteriaceae, total plate count, moulds and yeasts in cfu/g

Absence in 25 g is a sampling statement

'Salmonella not detected in 25 g' is only as strong as the number of 25 g units tested. Increasing the number of independent units tested is what raises confidence, not repeating the analysis on the same unit.

Recontamination after processing is the common failure

Heat treatment during processing controls the initial load; recontamination then happens in coolers, conveyors, transport and storage. Certificates issued at production do not describe the microbiological state at delivery.

What to verify

—Number and size of units tested, not just the pass statement
—Whether the certificate covers the delivered lot or the production batch
—Transport and storage conditions after processing
—Supplier's own hygiene monitoring and sanitiser programme

Typical risks

—Salmonella entry into a hatchery, breeder or dairy chain
—Cross-contamination of a whole mill after a single delivery
—Mould growth reducing nutritional value and generating toxins

Common mistakes

—Accepting a production-date certificate for a cargo stored for months
—Testing only finished feed and not incoming materials

Frequently asked questions

Which incoming materials deserve routine Salmonella testing?

Animal proteins, oilseed meals and any material with a history of positives in your own intake data. A risk-based plan concentrating on those, with periodic verification elsewhere, is more effective than uniform low-frequency testing.