Quantification of nisin in flow-injection immunoassay systems

A monoclonal-antibody-based, sequential competitive-flow-injection immunoas say system in expanded-bed mode has been developed for the determination of nisin. The system allows the determination of nisin in the presence of sus pended particles without any significant interference, illustrating its pot ential for on-line monitoring of fermentation processes or the analysis of food matrices. The dose response range of the system when operated in expan ded-bed mode was 6-90 mu M. The detection limit under packed-bed conditions was 3 mu M. The results correlated well with the results from conventional ELISA in the analysis of samples of processed cheese. When milk samples, f ermentation samples and buffer were spiked with nisin, the mean recoveries were 86% for milk samples, 96% for fermentation samples and 98% for buffer solution. (C) 2000 Elsevier Science S.A. All rights reserved.