Suitability of a bioluminescence method for examination cleaning and disinfection in food processing

The efficiency of cleaning and disinfecting surfaces was proved in the production line of a meat mincing plant, a fish processor and also in meat transport trucks. A bioluminescence technique was used to detect ATP from microorganisms and somatic cells. This method was compared with the results of conventional swab-methods. Examinations with known ATP- and microorganism- concentrations should reveal the sensitiveness of the bioluminescence method and show the correlation of microorganism-concentration and RLU as ATP-equivalents. These examinations yielded results to judge hygienic conditions in the above mentioned plants and transportation trucks. Following results were found: The smallest detectable concentrations for ATP are approximate 10(-14) bzw.(-15) Mol/test, for bacterials 10(3) cfu/test and for yeasts 10(2) cfu/test. Different bacterial strains showed a correlation-coefficient between concentration and RLU of 0.93, while two yeast generas showed one of 0.95. Appropriate cleaning and disinfection is indicated by RLU-levels smaller than 100. On easy-to-clean surfaces, RLU-levels smaller than 100 can be obtained without problem. Surfaces which are difficult to clean should not exceed RLU-levels of 500. The employed bioluminescence method seems to be well suited for monitoring cleaning and disinfection because not only microorganisms could detect but also organic soil.