Immunodot detection of nisin z in milk and whey using enhanced chemiluminescence

Abstract

A highly specific antisera was produced in New Zealand white rabbits against nisin Z, a 3400 Da bacteriocin produced by Lactococcus lactis ssp. lactis biovar. diacetylactis UL 719. A dot immunoblot assay was then developed to detect nisin Z in milk and whey. As few as 15 10-1 international units per ml (IU ml-1), corresponding to 0003 μg ml-1 of pure nisin Z, were detected in carbonate-bicarbonate buffer within 6 h using chemiluminescence. When milk and whey samples were tested, approximately 0.155 μg ml-1 (7.9 IU ml-1) of nisin Z was detected. The detection limit obtained was lower than that of traditional methods including microtitration and agar diffusion.