Comparative study of a semisynthetic derivative of natamycin and the parent antibiotic on the spoilage of shredded cheddar cheese.

A water-soluble N-alkyl semisynthetic derivative of natamycin was synthesized by the Michael addition reaction of the parent with an N-substituted malemide. A comparative study was carried out to investigate the effectiveness of the semisynthetic derivative and the parent antibiotic in suppressing mold growth on shredded Cheddar cheese stored in modified atmosphere packaging (MAP). The effects of 0-, 10-, and 20-ppm antimycotic treatments were examined. A 20-ppm natamycin treatment effectively suppressed visible mold growth (< 10(4) CFU/g) in MAP samples for up to 30 days after packages were opened. The performance of the 20-ppm semisynthetic derivative was similar to that of the 10-ppm natamycin treatment. For these treatments, visible mold growth did not occur in MAP samples until 20 days after packages were opened. These results indicate that the semisynthetic derivative of natamycin is less effective than the parent compound in suppressing mold growth on shredded Cheddar cheese.