CONFIRMATION OF THE VACUUM/STEAM/VACUUM PROCESS FOR THE REDUCTION OF BACTERIA ON CANTALOUPE USING A COMMERCIAL PROTOTYPE

Authors: GEVEKE, DAVID; KOZEMPEL, MICHAEL; FEZE, NELLY - ALKAR/RAPIDPAK - LODI, WI; VANG, TOU - ALKAR/RAPIDPAK - LODI, WI; JOHNSON, NOEL - ALKAR/RAPIDPAK - LODI, WI; Goldberg, Neil; HANSON, ROBERT - ALKAR/RAPIDPAK - LODI, WI; RADEWONUK, E

Submitted to: Fruit Processing
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/13/2007
Publication Date: 5/1/2007
Citation: Geveke, D.J., Kozempel, M.F., Feze, N., Vang, T., Johnson, N., Goldberg, N.M., Hanson, R., Radewonuk, E.R. 2007. Confirmation of the vacuum/steam/vacuum process for the reduction of bacteria on cantaloupe using a commercial prototype. Fruit Processing. 160-163.

Interpretive Summary: Cantaloupes are sometimes contaminated with bacteria and there have been outbreaks of food borne illness caused by consuming cantaloupes. We used a commercial prototype processor, that is under commercial development for hot dogs and that is based on the concepts of our vacuum/steam/vacuum (VSV) process, to destroy bacteria on the surface of fresh cantaloupes. This processor, which rapidly removes the insulating layers of air and water from the surface, permits condensing steam to rapidly destroy the bacteria with little or no thermal damage to the product. Bacteria inactivation ranged from 99.9% to over 99.99% of inoculated L. innocua for a range of total process times of 3.05 to 21.35 s respectively. This process provides a means for processors to supply cantaloupes to consumers having greatly reduced levels of bacterial contamination with no loss in product quality.

Technical Abstract: A prototype of a commercial Vacuum/Steam/Vacuum (VSV) processor was used to determine the effects of process conditions on microbial inactivation of Listeria innocua inoculated on whole cantaloupes. Effects of process conditions, including steam temperature, steam time and vacuum time were investigated. Steam temperatures investigated ranged from 127 to 143 C. Steam times and vacuum times ranged from 0.33 to 0.45 s, and 0.45 to 5.0 s, respectively. The cantaloupes were processed using three cycles; that is, VSVSVSV. The population of L. innocua was reduced by 3.0 log using a steam temperature of 138 C, and steam and vacuum times of 0.45 s. The total time for this process was 3.15 s. Inactivation was improved by increasing the vacuum time to 5.0 s, and correspondingly increasing the total process time. The commercial VSV prototype processor significantly reduced the population of Listeria innocua inoculated on cantaloupes.