3. Results and discussion
3.1. Initial contamination level of S. aureus in milk
The probability distribution for contamination level of S. aureus
in milk at the farm is shown in Fig. 2. The mean probable incidence
of contamination of S. aureus in milk derived from monitoring data
was 1.95 log CFU/mL, and ranged from 1.98 log CFU/mL (5%
percentile) to 1.93 log CFU/mL (95% percentile). As shown in Fig.1,
S. aureus can grow during transportation and storage in the dairy
processing plant or retail locations, since the storage temperature is
not always well controlled. The probability distribution of S. aureus
level in milk at processing plant and retail locations is shown in
Fig. 3. The contamination level of S. aureus in milk before processing
ranged from 1.97 log CFU/mL (5% percentile) to 0.67 log CFU/mL
(95% percentile) with a mean value of 1.25 log CFU/mL (Fig. 3a),
while the mean concentration of S. aureus in milk was 1.45 log
CFU/mL obtained after transportation to retail locations with the
range from 1.97 log CFU/mL (5% percentile) to 0.13 log CFU/mL