14C-5 |
Modeling Penicillium simplicissimum thermal resistance in milk jam spread. Influence of temperature and potassium sorbate |
S. S. CHRISTIAN, H. Gonzalez, S. Guerrero, and S. M. Alzamora. Department of Industry, Natural and Exact Sciences School, Buenos Aires University, Ciudad Universitaria, Nuñez, Buenos Aires, 1428, Argentina ²Dulce de Leche ² is an argentine sweet spread prepared from milk concentrated by evaporation to about 70 % w/w total solids (aw 0.80 to 0.85) at atmospheric pressure with added sucrose, glucose, and vanillin. Thermal resistance of xerophilic molds during hot filling could affect product safety and organoleptic quality during storage. The objective of this research was to analyze the influence of process temperature and presence of potassium sorbate on P. simplicissimum thermal resistance in ²Dulce de Leche ². ²Dulce de Leche ² systems (aw 0.84; pH 5,6) without and with potassium sorbate (1000 ppm) were inoculated with the mold suspension (107conidia/ml). The temperature was controlled to attain 65, 68 and 70 ° C during different experiences. Samples were taken at regular intervals along 30-minute treatment and monitored by plate counting technique. Each condition was assayed in duplicate. Collected data were modeled by applying Weibull distribution of resistances model. Typical sigmoidal survival curves were observed at all assayed temperatures. As temperature increased dramatic changes were observed on the frequency curve ¢ s shapes. The distribution’s mode, mean, and variance significantly decreased showing strong temperature influence. Potassium sorbate addition greatly increased the efficacy of the heat treatment, shifting the mode and rendering the Penicillium simplicissimum ¢ s distribution of resistances considerably narrower. This study contributed to optimize operation conditions in order to obtain a safer product when fails occur during the hot filling process or when the product is stored for a long period of time.
Session 14C, Food Microbiology: Food mycology
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