forty samples of ground beef were taken at four supermarkets in the city of piracicaba, sp. total bacterial counts were determined using a produre recommended by the american public health association; the plates were incubated at 32°c (48 hours). a modified procedure based on resazurin reduction for the determination of ground beef microbiological quality was studied. the results can be summarized as follows = 1) total counts were generally higth, with several samples in the range 107 to 109 cells/gram; the average count was 3,0 x 107 cells/gram. 2) the differences between counts related to any two supermarkets were not statistically significant. 3) resazurin reduction to colorless was significantly correlated with total bacterial counts (r=-0,91).