THE SURVIVAL AND RECOVERY OF SALMONELLA IN TUCSON'S WASTEWATER RECLAMATION PROGRAM

The fact that wastewater is a reser voir for Salmonella is well documented. However, the recovery of Salmonella from a wastewater sample is not a foregone conclusion (1) (2). A suc cessful recovery is dependent on many factors including the important un controllable factors of population inci dence rate and wastewater composi tion. Although wastewater is an arti ficially created depository for Salmon ella, the presence of soaps, fats, de tergents, and industrial wastes makes it a less than optimum environment for survival of the organisms. The water dilution factor makes it diffi cult to accumulate large numbers of Salmonella in a single specimen and the heterogeneity of the bacteria pop ulation does not enhance the isolation of those organisms which are not one of the predominant species. Salmon ella is rarely a predominant organism in this environment. In addition it has been postulated that bacterio phages may inhibit the survival and recovery of enteric organisms (3). It is difficult to assess the effect that any single factor may play in the isolation of Salmonella from waste water. Each factor probably con tributes to the interference of Salmon ella recovery, but the contributions will vary with the region and time.