A Rapid Surface Intervention Process to Kill Listeria innocua on Catfish Using Cycles of Vacuum and Steam

Abstract

The vacuum/steam/vacuum surface intervention process was applied to catfish surface inoculated with Listeria innocua. Studies were performed to determine the optimum process conditions of steam temperature, steam time, and number of cycles. Cycling the treatment significantly improved the microbiological kill. At the optimum conditions of steam time of 0.05 to 0.10 s at 143 Њ Њ Њ Њ ЊC and with 4 cycles, bacterial kill in excess of 2-log cfu/ml (colony forming units/ml) was attained. The surface intervention process should ensure that catfish reaching the consumer have greatly reduced levels or are free of Listeria contamination.

Dynamic measurement and mathematical modeling of the temperature history on hot dog surfaces during vacuum–steam–vacuum processes

“…With deboned chicken breast meats, the bacterial kill was 1-1.3 log (CFU/ml). Similar results were observed in the treatment of catfish using cycles of vacuum and steam (Kozempel, Marshall, Radewonuk, Scullen, & BalÕa, 2001b). Depending on the number of treatment cycles (1-3) and steam temperature (138 or 143°C), the observed bacterial kills ranged from 0.7 to 2.1 logs.…”

Reduction ofListeria monocytogeneson the Surface of Fresh Channel Catfish Fillets by Bacteriophage Listex P100

“…Further, there is a possibility for other foods to become cross contaminated by L. monocytogenes from catfish. Such a high occurrence of L. monocytogenes in fresh catfish products indicates the inadequacy of current intervention strategies for L. monocytogenes control in raw catfish products (Kozempel et al, 2001;Silva et al, 2003). Also, due to the potential for temperature abuse of raw products during storage and shipping, L. monocytogenes can multiply to dangerous levels under these conditions by readily available nutrients in these food products (Fernandes et al, 1998).…”

Recent Advances in Minimal Heat Processing of Fish: Effects on Microbiological Activity and Safety

“…Subsequent studies have revealed an inactivation rate in the range of log 2-4. When applied to catfish samples inoculated with L. innocua, a 3 log reduction was achieved by use of the VSV process (Kozempel et al 2001). Detailed temperature monitoring on hotdog surfaces during this process led Huang (2005) to hypothesise that a layer of condensate could act as an insulation blanket, which together with bacteria were filling pores and preventing the free access of steam, thereby possibly explaining the increased required steam processing time.…”