In a series of five experiments a total of 269 broiler carcass and chill tank water samples were tested for the presence of Salmonella using the DNA probe and the standard cultural method. Carcasses were sampled using a whole carcass rinse technique. Samples consisted of pre-(48) and post-chill (103) carcasses, and pre-chill (48) and chill (70) tank water. Samples to be evaluated with the DNA probe were subjected to three preenrichment/ enrichment procedures to determine the most accurate and reliable enrichment procedure to use with the DNA probe assay. Direct enrichment in Selenite Cystine followed by 24 h incubation in Gram Negative broth allowed for recovery of 0.03 salmonellae/ml from carcass rinse and from pre-chill water using either the standard cultural method or the DNA probe. Preenrichment in Lactose broth produced inaccurate results for prechill carcass and pre-chill water samples using the DNA probe assay, and may be due to extreme microbiological competition. No false positive results were obtained using the DNA probe assay for any of the four sample types.The food industry, governmental regulatory agencies, and the consumer have a vital interest in decreasing the incidence of salmonellosis and other foodborne diseases. Contamination of chicken carcasses with Salmonella is a source of human salmonellosis and is of continuing concern to both the poultry industry and public health authorities (17). Present technology utilized in slaughtering plants cannot guarantee a salmonellae-free finished product. Because of the increased public awareness of food poisoning bacteria and increased scrutiny by regulatory agencies, development of methods for rapid and reliable detection of foodborne Salmonella is indicated (18).Rapid methods including fluorescent antibody techniques (30,34,48,59,60), radioisotopic immunoassays (31,50,57), enrichment serology techniques (3, 5, 33, 34, 56, 57), enzyme immunoassays (39,45,58,63) screening and/or identification of various pathogenic organisms including Salmonella. Each of these methods is based on various characteristics of the organism. These rapid methods of analysis provide for the timely identification of contaminated products and reduce costs associated with storage of products pending microbiological clearance.It is possible to obtain results within 48 h using the DNA probe. This includes the time necessary for steps that must be completed prior to performing the actual DNA hybridization assay (25,26). Use of DNA-DNA hybridization for the detection of bacteria in clinical applications has been described by several groups. Encoded enterotoxins were cloned and used to detect enterotoxigenic E. coli both in colonies and directly from stools of patients suffering from acute diarrhea (46). A similar system has been used to detect enteropathogenic E. coli in food samples (35). DNA hybridization has also been applied to the detection of Leishamania spp., hepatitis B virus, cytomegalovirus, and 6,8,64).Cloned DNA fragments from S. typhimwium have shown high specifi...