Process and test kit for determining the bacterial count level in whey and whey products

Claim 1

A process for rapid determination of the bacterial count level in a sample of whey or whey constituents to be analyzed, said process comprising: a) preparing the sample for bioluminescence measurement by aa) wherein the sample is whey, aa1) diluting the whey sample with a reagent solution containing ethoxylate of 4-(1,1,3,3-tetramethylbutyl)phenol; aa2) separating the diluted whey sample by centrifugation into a liquid phase and an solid residue; aa3) converting the solid residue into a suspension by adding a reagent solution containing a bacteriolytic reagent; aa4) forming a reaction mixture by mixing the suspension with a reagent solution which hydrolyzes adenosine triphosphate; aa5) allowing the reaction mixture from step aa4) to react for a time sufficient to hydrolyze ATP present therein and to inactivate excess adenosine triphosphate hydrolyzing reagent; or ab1) introducing the whey constituent sample into an aqueous, isotonic salt solution; ab2) filtering the solution containing the sample through a sterile filter; ab3) transferring the filter with retained bacteria thereon into a nutrient solution suitable for culturing bacteria; incubating this solution for 1 to 9 hours at 28° C. to 38° C., and subsequently using the nutrient solution from above the filter as a reaction mixture for further measurement; b) releasing bacterial adenosine triphosphate in the reaction mixture obtained from process steps aa1) to aa5) or ab1) to ab3) by treatment with a reagent which releases bacterial adenosine triphosphate; c) adding to the reaction mixture a luciferin-luciferase reagent solution buffered to a pH value of from 7.0 to 7.9 in order to effect a bioluminescence reaction with released adenosine triphosphate; d) photometrically quantitatively measuring light emitted during the bioluminescence reaction, and e) determining the bacterial count level in the sample to be analyzed by comparing the measured light quantity with a standard curve produced under the same conditions with a sample of similar origin having a known bacterial count level.