Processing Conditions. Records of maintaining sanitary(aseptic) conditions during thermal processing have im proved by an order of magnitude or two during the past several decades, but to some degree, problems in this area also persist-probably mainly as the result of the tremen- dous throughputs of some processing plants and coupled with the appearance of processing innovations which sometimes reintorduce old problems. One of these prob- lems is container cooling water and is considered quality by some authorities as the primary source of microorga- nisms that cause leaker spoilage. The occurrence or rate of leaker spoilage is a function of the microbial contamina- tion level in the cooling water. Although food poisoning outbreaks occur infrequently, their seriousness when they do occur, is cause for constant concern. Defective seams are sometimes responsible, but the primary cause usually can be traced back to water used in can cooling. For example, outbreaks of both salmonella and Staphylococcus that occurred in the United Kingdom(Put et al., 1972) were traced to improper chlorination of cooling water 3