Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 5/3/2003
Publication Date: 11/28/2003
Citation: Kozempel, M.F., Goldberg, N.M. 2003. Vacuum/steam/vacuum - a process for killing surface bacteria on food without thermal damage. Meeting Abstract.
Technical Abstract: Solid foods such as chicken, fruits and vegetables, and ready-to-eat meats can harbor pathogenic bacteria causing food poisoning and product recalls. In addition to food poisoning, the recalls are very expensive for the food industry. We developed the Vacuum/Steam/Vacuum (VSV) process to destroy bacteria on the surface of solid foods. The process uses alternately vacuum and steam to kill bacteria on solid foods. To prevent thermal damage, it is necessary to limit steam exposure to milliseconds. By removing the surface layers of air and water with vacuum, applying steam for 0.1 s and evaporatively cooling the surface, there is little or no thermal damage. Use of multiple cycles substantially improves the process in reducing bacteria population densities. Depending on the food surface, the process kills 1 to 5 log of the surface microflora. Since hot dogs have a relatively smooth surface microbial reductions as high as 5 log can be achieved with the application of 3 cycles. The reductions on fruits and vegetables ranged from 2.5 to 4.7 log. For chicken carcasses, bacterial kill ranged from 1.1 to 1.6 log. The lower reduction on chicken carcasses may be attributed to the numerous areas for bacteria to ¿hide¿, such as in the cavity, feather follicles, skin and meat, under the wings and at both ends of the cavity. Most of the research was performed with surrogates, Listeria innocua and E. coli K12, but it was successfully applied to naturally occurring Campylobacter and E. coli. Commercialization is under way and will enhance the safety of the food supply, thereby reducing the incidence of food poisoning and expensive recalls.