The first group (five samples) was inoculated with 101 cfu mL-1 (low level), the second (five samples) with 102 cfu mL-1 (medium level), the third group (five samples) with 103 cfu mL-1 (high level). A fourth group was left un-inoculated to serve as negative control sample, and used to calculate the difference between artificial contamination and microflora of the milk, in a way such that would express only the value of the inoculum added at the different levels investigated.