Microbiological Quality of Water from Vending Machines

• Main Author: Tan, Ee Yau
• Format: Undergraduate Final Project Report
• Published: 2015
• Online Access: http://discol.umk.edu.my/id/eprint/6201/

Drinking water from vending machines may pose health risks to consumer. However, there is no previous study about the microbiological quality of water from vending machines in Malaysia. The aim of this study was to assess the relative safety of drinking water from vending machines. A total of 17 different water and swab samples from three different locations in Kelantan were collected. Microbial parameters such as aerobic plate count (APC), total coliform bacteria (TCC) and E. coil were examined. The results indicated that that 23.53% of the water samples from vending machines had aerobic plate count of greater than log 2.70 CFU/ml and thus did not comply with WHO drinking water standard. Total coliform was detected in 14 out of 17 (82.35%) water samples and E. coli were present in 11.76% of the water samples. The physico-chemical parameters such as temperature, pH and turbidity of water samples were examined. The results indicates that two parameters did not comply with the drinking water standard recommended by Malaysia Ministry of Health, WHO guidelines, European and international standard included turbidity limit >1 NTU. pH ranged between 6.23 and 8.75 for water samples and thus exceeded the limit of acceptance of WHO and EPA. The temperature of water sample was not significant for the microbial load. Preliminary test such as biochemical test, colony morphology and gram-staining were conducted. Isolated E. coli from vending machines no. 5 and no.12 were selected for DNA extraction. PCR and further 16S rRNA analysis were proceeded to identify strains of E. col/ using 16S Ribosomal Ribonucleic Acid (rRNA) analysis. The strains of E. coli analysed by Basic Local Alignment Search Tools (BLAST) from National Center for Biotechnology Information (NCBI) were Escherichia coli strain U 5/41 and Escherichia coli 0157:H7 str. EDL933.