ABSTRACT
This study aimed to evaluate a novel three-step sous-vide (SV) method on bacterial growth and diversity, and its relationship to product storage life. Vacuum-packed naturally contaminated steaks were sequentially cooked at 39⯰C (1â¯h), 49⯰C (1â¯h), and 59⯰C (4â¯h), then stored at -1.5 and 2⯰C for 28 d, with a single-step SV at 59⯰C for 4â¯h for comparison. None of the seven indicator bacteria tested proliferated (Pâ¯>â¯.05) after incubation at 39 or 49⯰C; microbial diversity was also unaffected. Bacterial load was reduced (Pâ¯<â¯.05) by up to 5 log units with both (Pâ¯>â¯.05) SV methods. The odour of all steaks remained acceptable on d 28. Unexpectedly, during storage, Pseudomonas, not lactic acid bacteria, dominated the microbiota on steaks cooked by either SV method, likely due to the temperature shift-induced lag phase and/or heat sensitivity of psychrotrophic bacteria. In conclusion, the three-step SV did not lead to bacterial proliferation or compromise the storage life of cooked products.