Prediction of the keeping quality of pasteurized milk by the detection of cytochrome c oxidase.
The keeping quality (KQ) of pasteurized milk samples stored at 5 degrees C and 10 degrees C was satisfactorily predicted after 18 h pre-incubation with 0.05% benzalkonium chloride at 20 degrees C, by estimating the numbers of Gram-negative psychrotrophic bacteria using the simple, cheap and rapid (5 min) assay of cytochrome c oxidase. Correlation coefficients for the relationship between cytochrome c oxidase activity at 20 degrees C and KQ at 5 degrees C or 10 degrees C of -0.89 and -0.84 respectively were obtained. The method correctly predicted the KQ of more than 89% of the samples of pasteurized milk. The assay was not satisfactory for use on samples after pre-incubation at 30 degrees C.
D000818:Animals; D001548:Benzalkonium Compounds; D002417:Cattle; D003576:Electron Transport Complex IV / Q000032:analysis*; D005516:Food Microbiology; D006090:Gram-Negative Bacteria / Q000201:enzymology*; D006358:Hot Temperature; D008892:Milk / Q000382:microbiology*; D013242:Sterilization; D013772:Tetramethylphenylenediamine
D001548:Benzalkonium Compounds; D003576:Electron Transport Complex IV; D013772:Tetramethylphenylenediamine