ICAR Research Data Repository for Knowledge Management

Protein-calorie rich "ready to eat" processed cereal food of low moisture content has often been
reported to contain aerobic mesophiles and coliforms. Codex Alimentarius Commission (1981) has laid down maximum limits of 10,000/ g of aerobic mesophilic count, 20/ g coliform count and zero toleranceof Salmonella for these products. Out of 225 samples analyzed, ten samples showed a high coliformcount. E. coli was also detected in these samples. The identification of the E. coli was confirmed bybiochemical tests. Three out of ten isolates were found to be atypical for fermentation of the sugarrhamnose. Antibiotic sensitivity tests showed increased resistance to the antibiotics Ampicillin,tetracycline, kanamycin and Arnikacin in isolates, when compared to the standard E. coli/1610(IMTECH, Chandigarh) isolate. Serotyping of the isolates showed that many of them belonged to thepathogenic group. Studies on the survival of E. coli in this food showed that a temperature of 25°C wasmore conducive than that at 35°C for survival. An initial count of 3 log10/g was reduced to less than 3 in 107 days(as determined by the Most Probable Number Completed Test Method) when samples were incubated at35°C. However, a count of 93 log10/ g was recorded in the samples incubated at 25°C even on the 120thday of storage. It was observed that storage of such samples at higher temperature led to a safer product.Of the two E. coli enumeration methods used, the Most Probable Number (MPN) Completed test methodwas found to be more reliable than the beta-Glucuronidase based method as the latter method could notdetect E. coli which did not possess the enzyme glucuronidase.