ATP bioluminescence method as a rapid tool for assessment of cleanliness of commercial animal transport trailers

Animal transportation is widely recognized as a significant risk for disease transmission. At present, cleanliness of animal transport trailers is mostly assessed through subjective visual inspection (i.e., ‘white-glove’ test), which may sometimes be supplemented by microbiological testing with results obtained after at least 2-3 days. In this study, the feasibility of using adenosine triphosphate (ATP) bioluminescence method as a rapid tool for objectively assessing animal transport trailer cleanliness was investigated. Eighteen newly-cleaned transport trailers were tested using both ATP bioluminescence and microbiological techniques. In each trailer, six (6) locations including floors, walls, ramps, partitions and trailer exterior surfaces were sampled using an ATP meter, and MacConkey and R2A agar contact plates. From a total of more than 500 paired samples collected from all the sampled trailers, significant correlation was found between ATP bioluminescence method and standard microbiological technique using R2A agar (r = 0.206; p = 0.001) and MacConkey agar (r = 0.154; p = 0.002) plates. Using a threshold or ‘Pass’ limit of 390 RLU per 100 cm2 of trailer surface, ATP method was able to provide a good objective measure of the surface cleanliness, thus may be considered as an additional tool available for rapid and less costly assessment of trailer surface cleanliness.