variation in results

the variation in the results of the different types of milk are to be expected as there are very different pasteurization processes involved. The average of the lite milk bacterial count and the full cream milk bacterial count are similar due to the similar pasteurization process, while the UHT milk is heated at high temperatures to kill the majority of bacteria.

also, there may have been some small, slight error while pouring the dilution onto the petri film for UHT resulting in a bacterial count higher in a dilution compared to pur UHT milk.