Location: Food Science Research
Project Number: 6645-41420-006-02
Start Date: Sep 01, 2011
End Date: Aug 31, 2014
This work will include the use of novel organic acid additives to acidified foods such as fumaric acid, which have recently been shown to be highly effective in killing enteropathogenic E. coli strains in acidified foods. Methods will include determination of the efficacy of combined organic acids on killing E. coli O157:H7 (and other enteropathogenic serotypes), Listeria monocytogenes, and Salmonella strains in acidified foods. Mathematical models of killing kinetics will be developed. Microbiological testing will include fractional factorial experimental design, spiral plating with automated plate reading, and 96 well microtiter plate most probable number techniques. These methods will significantly reduce the supplies and time needed to generate robust and repeatable killing curve data. Inoculated pack studies will include acidified vegetable products such as cucumber pickles (which lack antimicrobial phytochemicals), taking into account bacterial strain and product variation, pre-conditioning cells to acid stress, the sensitivity of acid injured cells to plating media, the effects of ionic strength and dissolved oxygen on acid stress, and other variables that could lead to “fail dangerous” conclusions.