Bacterial spore inhibition and inactivation in foods by pressure, chemicalpreservatives, and mild heat

Sucrose laurates, sucrose palmitate, sucrose stearates, and monolaurin (Lau ricidin) were evaluated for inhibitory effects against spores of Bacillus s p., Clostridium sporogenes PA3679, and Alicyclobacillus sp. in a model agar system. The combined treatment of sucrose laurate, high hydrostatic pressu re, and mild heat was evaluated on spores of Bacillus and Alicyclobacillus in foods. The minimum inhibitory concentrations of the sucrose esters were higher than that of Lauricidin for all spores tested in the model agar syst em, but Lauricidin was not the most readily suspended in the test media. Th e sucrose laurates and sucrose palmitate were more effective and more readi ly suspended than the sucrose stearates. A combined treatment of sucrose la urate (less than or equal to1.0%), 392 megaPascals (MPa) at 45 degreesC for 10 to 15 min provided 3- to 5.5-log(10) CFU/ml reductions from initial pop ulations of 10(6) CFU/ml for Bacillus subtilis 168 in milk, Bacillus cereus 14579 in beef, Bacillus coagulans 7050 in tomato juice (pH 4.5), Alicyclob acillus sp. N1089 in tomato juice (pH 4.5), and Alicyclobacillus sp. N1098 in apple juice. The most notable change in the appearance of the products w as temporary foaming during mixing of the sucrose laurate in the foods. The effect of sucrose laurate appeared to be inhibitory rather than lethal to the spores. The inhibitory effects observed on Bacillus and Alicyclobacillu s spores by the combined treatment of pressure, mild heat, and sucrose laur ate appear promising for food applications where alternatives to high heat processing are desired.