Acta Vet. Brno 2016, 85: 157-164
Seasonal dynamics and possible development of total count of microorganisms in sheep’s milk
The work is focused on the evaluation of seasonal dynamics of the total count of microorganisms in sheep’s milk and on the proposal of developing cut-off values for standard limitation for the next fifteen years for hygienic safety support. The total count of microorganisms was measured between years 2012–2014 (n = 4,746). The results were statistically evaluated using medians, geometric means, arithmetic means, means of log values (log10) and standard deviations for the cut-off limit determination. This model was patterned on the maximum of total count of microorganisms in the tested percentiles 95 (statistical conventional interval), 91, 90, 80 and 70% and on the result of medians (from 109 to 148 × 103 cfu/ml). These cut-off limits were divided into three classes (I to III) of standard quality, and the model of dynamics for their gradual implementation time was created as follows: initiation period (class I = ≤ 800; II = from 801 to 1,300; III = 1,301 to 4,000; non-standard = > 4,000 × 103 cfu/ml); second period (class I = ≤ 550; II = 551 to 800; III = 801 to 1,300; non-standard = > 1,300 × 103 cfu/ml); third period (standard class = ≤ 800 × 103 cfu/ml); fourth period (standard class = ≤ 550 × 103 cfu/ml); and the last legislative period (≤ 300 × 103 cfu/ml as a real hygienic limit). The limit for milk without heat treatment corresponds to the real value of the median 200 × 103 cfu/ml. The work is important for the procedures in the development of methods for the control and safety of raw food material.
Funding
This study was supported by the Slovak Research and Development Agency on the basis of Treaty APVV-0357-12 and by the Ministry of Agriculture of the Czech Republic with the project NAZV KUS QJ1230044 and by the Ministry of Agriculture of the Czech Republic (decision No. R01416).
