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Delayed Clostridium perfringens growth from a spore inocula by sodium lactate in sous-vide chicken products

Juneja, V.K.
Food microbiology 2006 v.23 no.2 pp. 105-111
prepared foods, sous vide, chicken meat, marinating, lactates, food additives, food packaging, vacuum packaging, food storage, storage temperature, Clostridium perfringens, bacterial spores, sporulation, food contamination, food pathogens, bacterial contamination, ready-to-eat foods, food preservation, shelf life, food microbiology, heat inactivation, inactivation temperature, plate count
Clostridium perfringens growth from a spore inoculum was investigated in vacuum-packaged, cook-in-bag marinated chicken breast that included 0%, 1.5%, 3%, or 4.8% sodium lactate (NaL; w/w). The packages were processed to an internal temperature of 71.1 °C, ice chilled and stored at 4, 19, and 25 °C. The total C. perfringens population was determined by plating diluted samples on Tryptose-sulfite-cycloserine agar followed by anaerobic incubation for 48 h at 37 °C. At 25 °C, addition of 1.5% NaL was effective in delaying growth for 29 h. Increasing the NaL level to 4.8%, C. perfringens growth from a spore inoculum during storage at 25 °C for 480 h was not observed. At 19 °C, the growth was >6 log(10) cfu/g by 288 h in control samples. In samples with 3.0% or 4.8% NaL, the growth of C. perfringens from spores was dramatically restricted with little or no growth in 648 h at 19 °C. C. perfringens growth was not observed at 4 °C regardless of NaL concentration. The D-values at 55 °C ranged from 47.40 (no NaL) to 57.58 min (1.5% NaL). Cyclic and static temperature abuse of refrigerated products for less than or equal to 20 h did not permit C. perfringens growth. However, temperature abuse of products for periods 24 h or longer in the absence of NaL led to growth of C. perfringens from a spore inoculum. An extra degree of safety may be assured in such products by supplementation with NaL at 1.5-4.8% NaL level.