US EPA

2775289 

Journal Article 

A STUDY ON THE LIQUID BACILLUS SUBTILIS REC-ASSAY FOR DETECTING THE DNA-DAMAGING ACTIVITY OF FOOD ADDITIVES 

Nonaka, M 

1991 

1 

Mutation Research Letters
ISSN: 0165-7992 

EMIC/85757 

253 

3 

English 

THE DNA-DAMAGING ACTIVITY OF FOOD ADDITIVES WAS EXAMINED BY THE LIQUID BACILLUS SUBTILIS REC-ASSAY. 0.1 ML DILUTED PRECULTURE OF B. SUBTILIS WAS MIXED WITH 0.1 ML TEST SOLUTION IN A 96-WELL MICROPLATE AND INCUBATED FOR 30 MIN OR 24 H AT 37 DEGREES C. AFTER A 30-MIN INTERACTION PERIOD BETWEEN THE BACTERIA AND THE TEST SOLUTION WITHOUT S9, THE MIXTURE WAS PLATED ONTO NUTRIENT BROTH AGAR PLATES AND THE NUMBER OF VIABLE CELLS WAS SCORED. AFTER A 24-H INTERACTION PERIOD, THE TURBIDITY OF THE MIXTURE WAS MEASURED AT 620 NM ON A MICROPLATE READER. IN ADDITION, THE R50 VALUE WAS CALCULATED, WHICH IS THE RATIO OF 50% SURVIVAL CONCENTRATIONS OF STRAINS REC+ AND REC-. FOUR SYNTHETIC FOOD ADDITIVES (ASCORBIC ACID, SODIUM BENZOATE, SODIUM DEHYDROACETATE AND HYDROGEN PEROXIDE) GAVE POSITIVE RESULTS IN BOTH ASSAY SYSTEMS. THE RESULTS SUGGEST THAT REDUCTION OF THE INTERACTION PERIOD IS ONE PROBLEM TO BE CONSIDERED.