Proteinase inhibition of the detection of Listeria monocytogenes in milk using the polymerase chain reaction

The direct detection, using the polymerase chain reaction (PCR), of Listeria monocytogenes added to cows' milk was inhibited at some milk concentrations. This inhibitor was moderately heat‐stable. Inhibition could be prevented by the addition of Bovine Serum Albumin (BSA) or proteinase inhibitors to the PCR and the evidence suggests that the inhibitor was plasmin.