Confirmatory test
Confirmatory tests are carried out following a presumptive positive result to determine whether STEC is present. These require the culture and isolation of E. coli colonies containing stx genes.
Negative result
A negative result means that it has not been possible to isolate an E. coli colony containing stx genes from the samples provided. Action is not required on negative confirmatory results provided there is no additional evidence that the food may be unsafe.
Positive result
A positive result means that presence of STEC has been confirmed by the isolation of an E. coli colony containing stx. The appropriate action will vary according to the food profile.