The effects of grapefruit seed extract on the thermal inactivation of listeria monocytogenes in sous-vide processed doner kebabs

Authors: HASKARACA, GULIZ - Sakarya University; Juneja, Vijay; Mukhopadhyay, Sudarsan; KOLSARICI, NURAY - Ankara University Of Turkey

Submitted to: Food Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/6/2018
Publication Date: 8/4/2018
Citation: Haskaraca, G., Juneja, V.K., Mukhopadhyay, S., Kolsarici, N. 2018. The effects of grapefruit seed extract on the thermal inactivation of listeria monocytogenes in sous-vide processed doner kebabs. Food Control. 95:71-76. https://doi.org/10.1016/j.foodcont.2018.07.006.
DOI: https://doi.org/10.1016/j.foodcont.2018.07.006

Interpretive Summary: Regulatory agencies and food industry 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 döner kebabs. The results suggest that supplementing döner kebabs with 0.5 – 1% grapefruit seed extract prior to sous vide processing can render the pathogen more sensitive to the lethal effect of heat. These findings will be of immediate use to the retail food service operations and regulatory agencies to ensure the safety of the sous vide processed foods.

Technical Abstract: The heat resistance (57.5 to 65C) of Listeria monocytogenes in vacuum packaged, cook-in-bag, döner kebabs that included 0.5 or 1% grapefruit seed extract (GSE) was determined. The packages were processed to an internal temperature of 57.5, 60, 62.5 or 65C in 1 h, held for a predetermined period of time, and then, ice chilled. The surviving cell population was determined by plating diluted samples onto tryptic soy agar overlaid with 10 ml of modified Oxford agar. Survivor curves were fitted to an equation based on the Weibull distribution using the USDA Integrated Pathogen Modeling Program 2013 software tool. The Weibull model consistently offered more accurate fit to all survivor curves based on the smaller root mean square error (< 0.46). The times to 4-log reduction were 140, 62.38, 14.45 and 6.84 min at 57.5, 60, 62.5, and 65°C, respectively. Supplementing döner kebab with 0.5 – 1% GSE rendered the pathogen more sensitive to the lethal effect of heat. The results provide the food industry with an option to supplement 0.5 – 1% GSE in sous vide processed döner kebab, that ensures adequate degree of protection against L. monocytogenes and at the same time, provide energy conservation and quality products.