top-banner copy (1)

Antimicrobial Preservative Improves Shredded Cheese Quality and Shelf Life

Previously found at

Check back periodically for original articles on topics ranging from new technologies to innovative product formulations to marketing dairy. Previous feature articles will be archived by date.

What types of fluorescent lamps are there?

Quality and performance are vital to maintaining consumer acceptance and sales of cheese in the United States. Despite the industry’s scrupulous attention to product superiority, however, natural enemies such as mold may sometimes hinder the quality-control process.

Researchers have found that the application of an antimicrobial preservative such as natamycin to cheese reduces the incidence of mold growth. Natamycin, which has been approved by the Food and Drug Administration (FDA) for use in the food industry, is particularly beneficial when used on shredded cheeses, which are especially prone to mold.

Yet two potential challenges still exist: the insolubility of natamycin in water, which makes it difficult to apply to cheese surfaces, and the degradation of natamycin’s stability during the ripening and storage of cheese.

Finding Food Quality Solutions Using Natamycin

Researchers Joseph E. Marcy, Ph.D., and John L. Koontz, of Virginia Polytechnic Institute and State University in Blacksburg, VA, have addressed these issues by forming molecular inclusion complexes of natamycin with cyclodextrins to increase its solubility and chemical stability.

Natamycin originates as a dry powder. To be applied to food products, it must be mixed in an aqueous solution to form a liquid. During the application process, however, aqueous natamycin suspensions can clog spray nozzles and prevent a uniform distribution of the substance onto the cheese surface.

The second hurdle is natamycin’s instability. Natamycin is extremely sensitive to ultraviolet (UV) light. “Cheese products are exposed to high-intensity fluorescent lighting in the retail dairy case, resulting in natamycin degradation on the cheese by the time of purchase by consumers,” said Marcy.

“In these inclusion complexes, we found that more than 90 percent natamycin remained in the aqueous solution and it was significantly more stable than free natamycin,” said Marcy, professor of food science and technology at the university. “When addressing the issue of stability, we found that product packaging helped to greatly reduce natamycin photodegradation.”

Marcy and Koontz are continuing their research, but agree that “the accomplishment of our original objectives should dramatically increase the antifungal efficiency of natamycin and, therefore, allow consumers to purchase shredded cheese products of greater quality.”