Preliminary Data on the Suitability of Alkaline Phosphatase Use as Pasteurization Indicator for Donkey Milk

Abstract

Donkey milk is a nutraceutical food that is becoming quite popular, especially in Mediterranean countries. Nevertheless, limited data exist on the safety of donkey milk. The European food hygiene regulations require pasteurized milk to show a negative reaction to an alkaline phosphatase test immediately after such treatment. This study aimed to assess whether alkaline phosphatase test is an adequate and suitable indicator of pasteurization specifically for donkey milk. Fresh donkey milk was collected from a farm in Greece, and the evaluation of the thermal inactivation of alkaline phosphatase was performed with various temperature and time combinations. A commercially available qualitative test for alkaline phosphatase detection in milk was used to assess its presence, while in parallel, samples were microbiologically tested (total viable count, Enterobacteriaceae, molds, and yeasts) using standard International Organization for Standardization methods. The main preliminary finding of this study was that alkaline phosphatase was deactivated in thermal combination of 56°C for 30 minutes which significantly differs from the classical ones used for pasteurization. The microbiological results, though, presented very low counts in raw and processed donkey milk. Alkaline phosphatase may not be suitable as a pasteurization indicator for donkey milk, and alternatives should be investigated. Copyright@Author(s) - Available online at actavet.org.