Bactericidal Effect of Ultrasound on the Microbiota of Raw Milk Cream

Abstract

The objective of this research was to evaluate the effect of Ultrasound on the microbiota present in raw milk cream in order to decrease the initial microbial load. Ultrasound offers an alternative in the conservation and preservation of food. The raw milk cream as a by-product of industrial processing is susceptible to deterioration by high microbial load and the presence of enzymes, which develop unwanted defects. The analysis did to themselves for triplicate, taking randomly a quantity average of cream, packed, labeled in Polyethylene bags low thickness (300 g) and refrigerated (4±2°C). The samples were evaluated microbiologically (mesophyll’s aerobic, total coliforms, fungi and yeasts), before and after treatment with ultrasound at a frequency of 37 KHz, with times of 2, 5 and 10 min, with temperatures of 30 and 40±2°C and stored in refrigeration (4±2°C) for 10 days (days 0, 3, 5, 7 and 10). The experimental data evaluated using a factorial design (time and temperature of exposure to US at 4 and 2 levels with three replicates for each treatment. An Analysis of Variance (ANOVA) was performed at a significance level of p≤0.05 and test POST HOC of Tukey using the statistical package SPSS v. 19.0 was shown that the treatment at 37 Hz for 10 min at a temperature of 40°C decreased the initial microbial load by 79%.