A quantitative ATP bioluminescence procedure has been used to determine the cleanliness of food processing factories and the results have been compared with those from conventional microbiological culture methods. ATP measurements were combined with the tissue or tissue fluid contamination (TTFC) assessment method to obtain an impression of the amount of inanimate contamination on the sampled surfaces. It was found that, in the sampled food factories, there was poor relation between the two assessment techniques: ATP bio-luminescence combined with TTFC and contact plating. However, either method in its own right is useful to check cleanliness of food industries. ATP measurements do have in addition the great advantage that it is a fast method and is easy to perform.