Page Banner

United States Department of Agriculture

Agricultural Research Service


Location: Food Science Research

Title: Thermal processing of acidified foods with pH 4.1 to pH 4.6

item Breidt, Frederick
item Kay, Kathryn -
item Osborne, Jason -
item Ingham, Barbara -
item Arritt, Fletcher -

Submitted to: Food Protection Trends
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 24, 2014
Publication Date: N/A

Interpretive Summary: For producers of acidified foods, the Food and Drug Administration requires that a scheduled process be submitted to the agency. This filing must be returned for commercial production of acidified foods, according to acidified foods regulations 21 CFR part 114. The process filings must have scientific data to show that the product is free of bacteria that can cause human disease, some of which are acid resistant. The research has shown time and temperature conditions needed to assure safety for thermal processing of acidified foods with pH values of up to 4.6, the upper pH limit for acidified food products. These data expand on previous published results for products with a pH of 4.1 or below. This work fills a critical gap in the scientific knowledge about the safe processing of these products. The results can be used by processors for FDA filings, and will assure safe production practices.

Technical Abstract: Acidified foods with a pH at or below 4.6 must be processed to achieve a 5-log reduction for vegetative bacterial pathogens. Published research does not exist to adequately support the Food and Drug Administration process filings for products with pH 4.1-4.6. This lack of documentation is challenging to all areas of the industry but especially for small processors. Using a non-inhibitory vegetable based medium, we developed models and data for the thermal destruction of acid resistant vegetative microbial pathogens, including 5-strain cocktails of Escherichia coli O157:H7, Salmonella enterica, and Listeria monocytogenes in acidified foods with a pH above 4.1 (pH 4.1-4.6). For the temperatures tested, Listeria monocytogenes was found to be the most heat and acid resistant pathogen. A z value of 16.7°F, an F value (at 160°F) of 5.6 min and a table of recommended processing conditions was derived from the thermal processing data.

Last Modified: 4/23/2014
Footer Content Back to Top of Page