Semi-log model for interpreting the results of swabbing surfaces naturally contaminated

Two mathematical models for depicting microbial depletions during six consecutive swabbings of refrigerated tank wall and teat skin were tested. Although a second degree polynomial equation gave a better adjustment of the data, a first degree equation was preferred to calculate the total numbers of micro-organisms possibly retrieved from surfaces by swabbing. This model was used for estimating the level of milk contamination by teat skin.