Comparison of Conventional and Rapid Methods for E.coli Testing in Water Sample

Abstract

Water is very important in food production, either as raw material for food processing, ice production, or for sanitation purposes. Water for food processing should meet the existing regulation for drinking water quality. According to the Guidelines for Drinking Water Quality World Health Organization and Keputusan Menteri Kesehatan No. 907/2002 the number of Escherichia coli and fecal coliform should be negative per 100 ml sample, consecutively. E. coli testing with conventional MPN methods needs 5-7 days thus it is not appropriate for food products with short expiry date. The aims of this study were to compare the performance of conventional and rapid methods used for testing of E.coli in process water and evaluate the implication of the application of rapid methods in a yogurt industry. The sample used in this study was process water from PT Yummy Food Utama, a yogurt and cheese industry. Total 30 samples of one litre each was taken from the process water tank outlet from 3 different days as a replication. The culture media used for the conventional methods were according to MPN of FDA/BAM and SNI methods. The culture media used for the rapid methods were Fluorocult LMX Broth (MPN), Chromocult Coliform Agar (TVC), and Readycult Coliform 100 (P/A). The result of this study showed that rapid methods reduced the testing time of E.coli from 5-7 days to 1-2 days only with an equal performance to conventional method but more convenience to do since it reduce of tubes and petridishes needed from 195 to 2-15 only. Even the rapid media Fluorocult LMX Broth showed the best recovery rate among other medias tested. Besides, rapid methods application saved the total cost by 71% with Readycult® Coliform 100 and Fluorocult® LMX Broth; 82% with Chromocult® Coliform Agar; and the possibility to increase the production capacity per month by 22%.