To quantitatively evaluate the production of staphylococcal enterotoxin A (SEA) in cooked rice, we inoculated 11 strains of SEA-producing Staphylococcus aureus into cooked rice, incubated the samples at 15-37 degrees C, and quantified SEA. The maximal concentrations of SEA were 0.0 (not detected) -4.0 ng/g at an incubation temperature of 15 degrees C, 0.4-8.4 ng/g at 20 degrees C, and 2.3-53.8 ng/g at 37 degrees C with an inoculum size of 10(6) CFU/g. There were few correlations among the maximal concentrations of SEA at incubation temperatures of 15, 20, and 37 degrees C or between the maximal concentrations of SEA produced in a liquid medium and in cooked rice. Although the predicted amounts of SEA produced in a rice ball under conditions of 16 h of incubation at 20 degrees C or 4 h at 37 degrees C appeared to reach levels capable of causing staphylococcal food poisoning, S. aureus growth under these conditions was not organoleptically detected.