Inactivation of Bacillus sporothermodurans spores by nisin and temperature studied by design of experiments in water and milk

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• 作者：Chedia Aouadhi ; Zeineb Rouissi ; Slah Mejri ; Abderrazak Maaroufi
• 关键词：Nisin ; Bacillus sporothermodurans ; Spore ; Inactivation ; Response surface methodology ; Temperature
• 刊名：Food Microbiology
• 出版年：April, 2014
• 年：2014
• 卷：38
• 期：Complete
• 页码：270-275
• 全文大小：394 K

文摘

Spores of Bacillus sporothermodurans are known to be a contaminant of dairy products and to be extremely heat-resistant. A central composite experimental design with three factors using response surface methodology was used to evaluate the effect of nisin (50-150聽UI/mL), temperature (80-100聽掳C), and temperature-holding time (10-20聽min) on the inactivation of B.聽sporothermodurans LTIS27 spores in distilled water, in skim milk and in chocolate milk. The experimental values were shown to be significantly in good agreement with the values predicted by the quadratic equation since the adjusted determination coefficients (R_adj²) were around 0.97. By analyzing the response surfaces plots, the inactivation was shown to be higher in distilled water than in skim milk under all the conditions tested. Five-log cycle reductions of B.聽sporothermodurans spores were obtained after a treatment at 95聽掳C for 12聽min in presence of 125聽UI of nisin/mL in distilled water or at 100聽掳C for 13聽min in presence of 134聽UI of nisin/mL in skim milk or at 100聽掳C for 15聽min in presence of 135聽UI of nisin/mL in chocolate milk. This study showed the efficiency of nisin (15-184聽UI/mL) in combination with temperature (73-106聽掳C) to inactivate spores of B.聽sporothermodurans in milk.