The eight UHT-heated milk samples were stored at 6C and 20C until the end of shelf life expiry date. Table 6 shows ALP activities after a storage period of 2 weeks and at the end of shelf life expiry date. At a storage temperature of 6C, only negligible changes in activity were found, however, at a storage temperature of 20C a significant increase in ALP activity was detected at the end of shelf life expiry date. LPO reactivation could not be determined in UHT milk until the end of shelf life. The detected enzyme activities were below the measurement level of