The Effect of High Pressure on the Microbial Quality of Apple Juices

摘要

Six fresh apple juice samples were exposed to high pressure treatments, ranging from 250 to 400 MPa for 5 min at 20 deg C. All the juices exhibited a significant reduction in total viable counts immediately post pressurisation. The pressurised samples were stored at 4 deg C and sampled monthly. Counts from juices pressurised up to 350 MPa increased after 1 months storage, whereas 400 MPa treated juice did not increase in counts until 2 months storage. The surviving microbial population of the juices was found to be predominately yeasts, e.g. S. cerevisiae, Candida species, Zygosaccharomyces spp. and Rhodotorula spp., and moulds, e.g. Penicillium spp.