Effects of a novel three-step sous-vide cooking and subsequent chilled storage on the microbiota of beef steaks
Citation
Yang, X., Wang, H., Badoni, M., Zawadski, S., McLeod, B., Holman, D., Uttaro, B. (2020). Effects of a novel three-step sous-vide cooking and subsequent chilled storage on the microbiota of beef steaks. Meat Science, [online] 159 http://dx.doi.org/10.1016/j.meatsci.2019.107938
Plain language summary
We evaluated 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 cooked at 39 °C (1 h), 49 °C (1 h), and 59 °C (4 h), then stored at −1.5 and 2 °C for 28 d. A single step SV at 59 °C for 4 h was included for comparison. None of the seven indicator bacteria increased after incubation at 39 or 49 °C; the bacterial community composition was also unaffected. Both SV methods reduced the bacterial numbers by up to 5 log. The odour of all steaks remained acceptable on d 28. In conclusion, the three-step SV did not lead to bacterial proliferation or compromise the storage life of cooked products.
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 (1 h), 49 °C (1 h), and 59 °C (4 h), then stored at −1.5 and 2 °C for 28 d, with a single-step SV at 59 °C for 4 h for comparison. None of the seven indicator bacteria tested proliferated (P > .05) after incubation at 39 or 49 °C; microbial diversity was also unaffected. Bacterial load was reduced (P < .05) by up to 5 log units with both (P > .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.