I'm working on a hazard analysis for a sour cream (non-dairy), and B. cereus was identified as a potential hazard introduced with ingredients. The manufacturing process is: batching > pasteurizing (pH neutral) > inoculation of LAB culture and agitation for 1 h > filling in cups > fermentation in incubator at 113F to pH of 4.4 > cold storage.
Spores of B. cereus typically survive pasteurization and may germinate and grow, but they will not have much time to grow before the LAB culture grows reducing the pH. As the pH drops, vegetative cells of B. cereus will significantly decrease. If all happens quickly, B. cereus will also not produce toxins. Because of that it doesn't seem like B. cereus is of safety concern in yogurt and similar products. The combination of rapid fermentation and pH drop seems to be key to ensure safety, and this is easily achieved when you ferment the white mass inside the tank, right after pasteurization. https://www.mpi.govt...ment/14149/send
However, in the case I'm working on, for organoleptic reasons, the fermentation should occur inside the cups, i.e. the inoculated mass is filled in cups and taken to an incubator to ferment. The process of filling cups can take up to 8 h. It was recommended to drop the temperature of the tank to 90-100F to slow down the fermentation while the batch is filled (fermenting inside the tank defeats the purpose of the cup set product). My concern is that the inoculated mass will spend too much time (up to 8 h) in the tank at higher pH (5-7), and with less competition, since the ideal temperature for the culture to grow is ~113F. B. cereus could grow more and eventually produce toxins.
Has anyone worked with cup set fermented products? What would be the maximum time at this condition (pH 5-7; temperature 90-100; less competition) to prevent B. cereus to produce toxins? Any thoughts on the validation of this preventive control?
This forum has helped me so much in the past. I hope someone will be able to guide me in the right direction this time again.
Edited by apcraig, 07 May 2019 - 03:44 AM.