Research to Improve Cheese Quality

Researchers Joseph E. Marcy, Ph.D., and John L. Koontz – with funding from America’s dairy farmers – is inhibiting mold growth on the surface of cheeses by leveraging natamycin, an antimicrobial preservative approved by the Food & Drug Administration (FDA) for use in the food industry. Natamycin is particularly beneficial when used on shredded cheeses, which are especially prone to mold.

Early in their research, Marcy and Koontz pinpointed and are successfully addressing two potential challenges: Natamycin is practically insoluble in water and its stability is degraded during the ripening and storage of cheese.

Natamycin’s tendency toward insolubility makes it difficult to apply to cheese surfaces. In its original form, natamycin is a dry powder that must be mixed in an aqueous solution to form a liquid that can be applied to food products. However, during that application process, aqueous natamycin suspensions can clog spray nozzles and prevent a uniform distribution of the substance onto the cheese surface.

Once the spraying hurdle is overcome, the second part of the challenge arises.

“In terms of stability, natamycin is extremely sensitive to ultraviolet (UV) light,” said Marcy, professor of food science & technology at Virginia Polytechnic Institute and State University in Blacksburg, VA. “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.”

Marcy and Koontz set out to increase the water solubility and chemical stability of natamycin to improve the delivery system and product quality of shredded cheese. The project was conducted with funding from DMI, the domestic and international planning and management organization that builds demand for U.S.-produced dairy products on behalf of America’s dairy farmers.

Marcy and Koontz addressed these issues by forming molecular inclusion complexes of natamycin with cyclodextrins in order to increase its solubility and chemical stability.

“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. “When addressing the issue of stability, we found that product packaging helped to greatly reduce natamycin photodegradation.”

Though the research is ongoing, the results to date are promising.

“The accomplishment of these objectives should dramatically increase the antifungal efficiency of natamycin and, therefore, allow consumers to purchase shredded cheese products of greater quality,” concluded Marcy.

For more information on DMI’s research on natamycin, contact the toll-free Technical Support Hotline at 1-800-248-8829.