Microbiological risk assessment of packed fruit juices and Antibacterial activity of preservatives against bacterial isolates

The present study was conducted to assess the microbial load of packed fruit juices and determine anti-bacterial activity of the preservatives used in preparation of these fruit juices. apple,mango and orange fruit juice samples (n=90) of five brands collected from retail shops and vendors were subjected to conventional cultural and biochemical methods for microbial enumeration. antibacterial activity was analyzed using agar well diffusion method. microbiological analysis of fruit juice samples demonstrated the presence of total viable counts (3.23±0.29 to 7.28±0.41 log10 cfu/ml),total staphylococcal counts (0.00±0.00 to 4.89±0.83 log10 cfu/ml),total coliform counts (0.00±0.00 to 4.48±1.03 log10 cfu/ml) and total fungal counts (1.75±0.58 to 4.40±0.20 log10 cfu/ml). comparative evaluation showed that fruit juices of brands d and e were highly contaminated as these were local brands. the isolated microbes include bacillus spp.,staphylococcus aureus,escherichia coli,aspergillus spp.,saccharomyces cerevisiae,penicillium sp. and rhizopus. among the preservatives used,citric acid was found to exhibit highest antibacterial activity. ascorbic acid was active against 2 out of 3 bacteria. no activity was found against sodium benzoate. it is concluded that microbial load in packed fruit juices is significantly higher than standard permissible limits and most preservatives used in manufacture are of low quality which insinuates its possible role in spoilage and food borne illnesses. periodic monitoring of packed fruit juices should be carried out to make them safe for consumption. copyright 2016 zoological society of pakistan.