CONTAGEM DE BACTÉRIAS HETEROTRÓFICAS NA ÁGUA PARA CONSUMO HUMANO: COMPARAÇÃO ENTRE DUAS METODOLOGIAS Heterotrophic bacteria counting in the drinking water: comparation between two methodologies

SUMMARY The counting of heterotrophic bacteria widely applied as an indicator of the quality of drinking water. In order to perform the counting, the microorganisms are detected by propagation in non-selective culture media. The objective of the present work was to compare the methodologies of "Pour Plate" and streaking on the surface of the plate for the counting of heterotrophic bacteria in water. The water samples were collected from July 11 to November 10, 2005, from 43 artesian wells and alternative sources of the Santa Maria region. The analyses results showed that the sowing for exhaustion presented a higher sensitivity (58.2%) as compared to the "Pour Plate" method (9.2%). There was colony number compatibility in 32,6% of the samples analyzed by both techniques. The results suggest a better performance for streaking on the surface as compared to the "Pour Plate" method.