ADSORPTION OF BACTERIOCINS BY INGESTIBLE SILICA COMPOUNDS

Bacteriocins including nisin, pediocin PO2, brevicin 286 and piscicoli n 126 were adsorbed from culture supernates by various food-grade poro us silica anti-caking agents and the food colourant, titanium dioxide. All the porous silica (calcium silicate or silicon dioxide) materials showed substantial capacity in adsorbing bacteriocin activities from the culture supernate and biological activity was recovered in the ads orbents. In contrast, the food colourant titanium dioxide adsorbed mos t of the bacteriocin activity from the supernate, with minimal biologi cal activity retained in the adsorbent. Experiments with piscicolin 12 6 showed that optimum adsorption could be achieved with Micro-Cel E wi thin 30 min, independent of the supernate pH (2.0-10.0). Piscicolin ac tivity of up to 5 x 10(7) AU g(-1) of Micro-Cel E was obtained after a dsorption from culture supernates and the adsorbed piscicolin demonstr ated substantial biological activity against Listeria monocytogenes in both broth and a milk growth medium.