発展途上国 (タイ) における食品微生物検査法の検討

抄録

For the surveillance purpose of microbial contamination of foods and utensils, we have devised a new method which is simple, inexpensive, and accurate enough. One of the basic ideas is to see color change of pH indicators in media due to the acid production from lactose by the growth of contaminating Coliform group. This test method was designated as SI-test (Sanitary Indicator test).
These media were sensitive enough to detect the viable organisms of less than 10 in the model experiment with the standard strain of E. coli. A good correlation was obtained between viable count of the inoculate and the reaction time (the initiation of color change). This was possible within 24 hrs even when the inoculated media were left to stand at room temperature (around 30°C).
Then, these media were subjected to the evaluation test with a total of 152 selected specimens including 90 food samples, 17 water and beverage samples, and 45 swabbed samples. The test was rewarded with satisfactory results promising the high efficiency in practical use.
To make this method applicable even in the peripheral laboratories of rural areas, the thik paper disks absorbed with the concentrated media were prepared. The disks can be reconstituted by addition of sterized saline or water before use. When preserved in a refrigerator, the quality of the disks did not change for at least 180 days. In view of these results, we concluded that the methd as devised here is worthy of the practical use in the laboratories of limited facilities and equipments.