CHALK AND FLUID INOCULATION METHODS IN STUDYING THE PERCENT RECOVERY OF CLOSTRIDIUM PERFRINGENS, ESCHERICHIA COLI AND ENTEROCOCCUS FAECALIS FROM RAW GROUND BEEF

Abstract

The fluid inoculation method is widely used in studying the growth characteristics and percent recovery of microorganisms in food. In addition to this method a new method, called the chalk method, was introduced and has been successfully used. This research aimed to compare the percent recovery of Clostridium perfringens, Escherichia coli and Enterococcus faecalis from raw ground beef using the chalk and fluid inoculation methods. It also aimed to compare the chalk and fluid methods in studying the percent recovery of the three microorganisms. The results show that the percent recoveries of C. perfringens, E. coli, and E. faecalis were significantly different (P Ͻ 0.05) using the two inoculation methods, except for the percent recovery of C. perfringens and E. coli using the fluid method (P Ͼ 0.05). The percent recovery using chalk powder inoculum was significantly lower (P Ͻ 0.05) than the percent recovery using fluid inoculum for E. coli and E. faecalis. The results also show that E. faecalis has the highest percent recovery using both methods, and E. coli has the lowest using the chalk method. It can be concluded that chalk inoculation is better than fluid inoculation because it gives better percent recovery, saves time, is easier to perform, is more precise, and gives information about inoculum distribution.