Submitted to: Journal of Food Protection
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/5/2016
Publication Date: N/A
Citation: N/A Interpretive Summary: Risk assessors and food safety managers continue to express concerns about the public-health risks associated with sous vide processed foods because the mild heat treatment required to retain the organileptic attributes may not ensure proper destruction of the deadly bacterium, Listeria monocytogenes. Therefore, there is a need to determine time and temperature required to destroy the pathogen in sous vide processed marinated meat products. The results suggest that 800 ppm of a commercial grapefruit extract added to marinated products prior to sous vide processing can render the pathogen more sensitive to the lethal effect of heat. We developed a predictive model for estimating heat treatment required for destruction of this pathogen in sous-vide processed Mexican meat entrées. These findings will be of immediate use to the retail food service operations and regulatory agencies to ensure the safety of the sous vide foods.
Technical Abstract: D and z values of Listeria monocytogenes were obtained for two Mexican meat entrées: pork meat marinated in tomatillo (green tomato) sauce (PTS) and beef marinated in a red chili sauce (BRCS), with addition of 0, 200 and 800 ppm of grapefruit seed extract (GSE). Meat samples, inoculated with L.monocytogenes, were packaged in sterile bags, immersed in a water bath and held at 55, 57.5, 60 and 62.5C for different periods of time. Depending upon the temperature, D-values at 0 ppm GSE ranged from 26.19 to 2.03 min in BRCS and 26.41 to 0.8 min in PTS. Adding 800 ppm of GSE to BRCS thermally treated at 55, 57.5, and 60C significantly decreased the inactivation time by 34.9, 9.1 and 11.4%, respectively. A reduction in time of 25.8, 10.6, and 40.1%, at 55, 57.5 and 60 degrees C, respectively, was observed in PTS with 800 ppm GSE. The z values of L. monocytogenes ranged from 7.13 to 6.8 degrees C in BRCS and 4.55 to 4.99 degrees C in PTS at 0 and 800 ppm GSE, respectively. Estimated thermal lethality, for a 7-D Log10 reduction of L. monocytogenes, under commercial-size sous-vide conditions at a reference temperature of 62.5 degrees C, was reached at 77 and 70 min for BRCS and PTS, respectively. Supplementing both Mexican meat entrées, BRCS and PTS, with 800 ppm of GSE rendered L. monocytogenes cells more sensitive to the lethal effect of heat. The results of this study will assist the retail food industry to design acceptance limits on critical control points pertaining to cooking regimes to effectively eliminate L. monocytogenes in BRCS and PTS sous-vide processed Mexican meat entrées.