Interpretation and extraction useful information from irregular fluctuating industrial microbial counts

Irregular fluctuating patterns of industrial microbial records arise because certain factors that affect them vary in a random fashion. If the counts are independent, and their series stationary with no trend or periodicity, a probabilistic model based on an asymmetric distribution function can be used to estimate the frequency of counts exceeding any given magnitude. Industrial records of standard plate counts (SPC), anaerobes, and thermophiles in 4 dairy products were characterized with the lognormal distribution. Many of the records had weak but significant autocorrelations for small lags, indicating that successive lots had similar microbial loads. Nevertheless, in almost all cases the method provided reasonable estimates of future counts frequencies, which were confirmed with fresh data