A PCR procedure was developed for the detection of Clostridium botulinum in foods. PCR products were detected in agarose gels and by Southern hybridization. The sensitivity of PCR was tested in broth cultures and in canned asparagus, dry cured ham and honey. The sensitivity of the method in broth was high (2.1-8.1 cfu ml-1) for types A and B, but rather low (10(4) cfu ml-1) for types E and F. However, after enrichment at 37 degrees C for 18 h, it was possible to detect Cl. botulinum types A, B, E and F in food samples at initial levels of about 1 cfu 10 g-1 of food. This PCR detection protocol provides a sensitive and relatively rapid technique for the routine detection of Cl. botulinum in foods.