The Use of Digoxigenin-labeled Oligonucleotide Probes for the Specific Detection of Salmonella in Foods
SHU-JEN WANG1, SHIEN-FENG GONG2 AND HAU-YANG TSEN3
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Department of Food Hygiene. Chia-Nan College of Pharmacy and Science , Tainan, Taiwan, R.O.C.
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Department of Food Hygiene.Da-Ren Junior College of Pharmacy, Ping tung,Taiwan,R.O.C.
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Department of Food Science,National Chung-Hsing University, Taichung, Taiwan,R.O.C.
ABSTRACT
Three oligonucleotide fragment TS11 ,TS21 and TS31 were labeled with digoxigenin, and the hybridization specificities for three oligonucleotides confirmed with Salmonella and non-Salmonella isolates. Three non-radioactive oligonucleotide probes were used for the specific detection of Salmonella in contaminated food samples, including pork, fish and shrimp samples. It was found that enrichment of Salmonella in food samples using lactose combined tetrathionate broth followed by streaking of the culture on Salmonella-Shigella agar and spotting suspected cells on nitrocellulose paper placed on Luria agar prior to colony hybridization yield unambiguous results. Salmomella at 3 cfu per gram of food could be detected.
Key words: Salmonella, digoxigenin, oligonucleotide probe