Purified and crude samples were subjected to SDS-PAGE(4–20%) and revealed with silver (Fig. 4). The gels showed the“smiley effect”, probably due to high salt content in somesamples. Purified samples showed no bands but nisin, inagreement with nisin activity (high) and protein content (low)assays. As expected, commercial nisin (not purified, Fig. 3B)showed multiple bands and contained high protein content.