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D VALUES OF COMPOSITE SALMONELLA ENTERICA SEROTYPES TYPHIMURIUM AND ENTERITIDIS IN PHILIPPINE NATIVE ORANGE JUICE
Author(s) -
GABRIEL ALONZO A.
Publication year - 2007
Publication title -
journal of food processing and preservation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.511
H-Index - 48
eISSN - 1745-4549
pISSN - 0145-8892
DOI - 10.1111/j.1745-4549.2007.00156.x
Subject(s) - food science , salmonella , salmonella enteritidis , agar , orange juice , orange (colour) , citric acid , chemistry , sugar , salmonella enterica , pasteurization , microbiology and biotechnology , biology , bacteria , genetics
This study established the decimal reduction times ( D values) of a composite inoculum of Salmonella enterica serotypes Typhimurium (American Type Culture Collection 13311 and E 1366) and Enteritidis (BIOTECH 1963) in Philippine native orange juice (pH 3.0, 0.84 % citric acid, 8.4°Brix). Acid‐adapted cells (10 log 10 cfu/g) were heated to 50–70C for 0–1.5 min and recovered by surface plating onto a selective (bismuth sulfite agar) and a nonselective medium (nutrient agar [NA]). Results showed that in both enumerating media and in all heating temperatures, survivor populations significantly decreased ( P < 0.05) with increasing treatment time. The greater populations enumerated on NA in all treatment times were attributed to the sublethal injuries imparted by the acidity of the suspending medium and the heat treatments. The D values calculated from the survivor populations on both media were not significantly different ( P > 0.05). The D values ranged from 0.16 to 0.40 min.PRACTICAL APPLICATIONS This study established the thermal inactivation rates of a composite Salmonella spp. inoculum in a Philippine orange juice medium. Salmonella is a target organism pertinent in the assuring citrus juices. Hence, appropriate thermal process schedules for citrus juices with similar physicochemical properties as the test medium, against the test organisms may be calculated using the results obtained from this study.