Occurrence of coliform bacteria other than Escherichia coli in foods.

An evaluation of the BGLB (44 degrees C) confirmation test for the enumeration of E. coli as an index of sanitary quality of some foods was made. Out of 70 samples tested, 43 (61.4%) samples contained E. coli. A total of 347 BGLB gas positive cultures obtained were subjected to the IMViC procedure. It was found that 42.7% of these BGLB gas positives were E. coli and 57.3% were ten other coliform bacteria giving the following IMViC patterns: 31.4% --++, 6.3% -+-+, 4.3% each of +-++ and -+++, 3.2% ++-+, 2.9% ++++, 2% ---+, 1.4% +++-, 1.2% --+- and 0.3% -++-. Some of the possible reasons for obtaining low recovery of E. coli in foods by the BGLB test have been discussed. The various fields to be investigated for the improvement of the test procedure and thus the elimination of false positives have been suggested.

A bacteriological study of some frozen and nonfrozen foods.

Over a period of 19 months, a total of 331 food samples were submitted to the Food Section of the Bacteriology Division for bacteriological examination. These included 184 samples of frozen seafoods from exporters and 147 samples of fresh, nonfrozen foods from food caterers. The total bacterial count for frozen seafoods ranged from 1 x 10(2) to 2.98 x 10(6) per gm with a mean of 2.14 x 10(5) per gm. Coliforms, Escherichia coli and Staphylococcus aureus were present in 48.9%, 3.3% and 8.2% of the samples examined respectively. Two of the cooked prawn samples showed the presence of Vibrio parahaemolyticus. For the fresh, nonfrozen foods, the total bacterial count ranged from 1 x 10(2) to 3.87 x 10(6) per gm with a mean of 2.58 x 10(5) per gm. The examination also showed that 74.8% were coliform positive, 14.9% were E. coli positive, and 4.8% were S. aureus positive. V. parahaemolyticus was not isolated in any of the samples tested. Other pathogens, namely, Vibrio cholerae, Salmonella and Shigella were not isolated from any of the foods examined. The bacterial levels in these foods were determined and their sanitary and public health significance is discussed.