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Research Project: Improved Processes for the Preservation and Utilization of Vegetables, Including Cucumber, Sweetpotato, Cabbage, and Peppers to Produce Safe, High Quality Products with Reduced Energy Use and Waste

Location: Food Science Research

Title: Survival and growth of probiotic lactic acid bacteria in refrigerated pickle products

Author
item FAN, SICUN - NORTH CAROLINA STATE UNIVERSITY
item Breidt, Frederick
item PRICE, ROBERT
item Perez Diaz, Ilenys

Submitted to: Journal of Food Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/9/2016
Publication Date: 1/1/2017
Publication URL: http://handle.nal.usda.gov/10113/5642512
Citation: Fan, S., Breidt, F., Price, R.E., Perez Diaz, I.M. 2017. Survival and growth of probiotic lactic acid bacteria in refrigerated pickle products. Journal of Food Science. 82(1):167-173.

Interpretive Summary: The development of probiotic pickle products will be facilitated by identifying probiotic cultures that can survive in acidified vegetable products. We analyzed the growth and acid resistance of ten probiotic lactic acid bacterial cultures to determine which cultures may be best to use for refrigerated pickle products. Results showed that there is significant variation among probiotic bacterial strains, and we found that cultures selected by these methods had superior long-term survival (up to 2 months) in a simulated refrigerated probiotic vegetable product that included a fermentation step. These data may be useful to aid the development of commercial probiotic pickles.

Technical Abstract: We examined 10 lactic acid bacteria that have been previously characterized for commercial use as probiotic cultures, mostly for dairy products, including 1 Pediococcus and 9 Lactobacilli. Our objectives were to develop a rapid procedure for determining the long-term survivability of these cultures in acidified vegetable products and to identify suitable cultures for probiotic brined vegetable products. We therefore developed assays to measure acid resistance of these cultures to lactic and acetic acids, which are present in pickled vegetable products. We used relatively high acid concentrations (compared to commercial products) of 360 mM lactic acid and 420 mM acetic acid to determine acid resistance with a 1 h treatment. Growth rates were measured in a cucumber juice medium at pH 5.3, 4.2, and 3.8, at 30 °C and 0% to 2% NaCl. Significant differences in acid resistance and growth rates were found among the 10 cultures. In general, the acid resistant strains had slower growth rates than the acid sensitive strains. Based on the acid resistance data, selected cultures were tested for long-term survival in a simulated acidified refrigerated cucumber product. We found that one of the most acid resistant strains (Lactobacillus casei) could survive for up to 63 d at 4 °C without significant loss of viability at 108 CFU/mL. These data may aid in the development of commercial probiotic refrigerated pickle products.