Antibacterial coating may boost seafood industry

woman in lab

Katherine Rubio inoculates crab meat with bacteria at the Kodiak Seafood and Marine Science Center.

A research project underway this summer in Kodiak has the potential to boost the Dungeness crab industry, valued at an average of $9 million per year in Alaska. Katherine Rubio is testing the antibacterial effect of chitosan as an edible film on cooked Dungeness crab products.

Rubio is an intern with Alaska Sea Grant and the Alaska Seafood Marketing Institute (ASMI) working in the science labs at the Kodiak Seafood and Marine Science Center. The center is part of the University of Alaska Fairbanks, College of Fisheries and Ocean Sciences.

Chitosan, a long-chain sugar or polysaccharide extracted from shrimp shells and crab shell waste, is used as a natural antifungal seed coating in agriculture. Chitosan can also improve the storability of perishable foods and can potentially prevent illness from spoiled foods.

“The increasing demand for convenience food products coupled with the lack of knowledge by consumers on how to store ready-to-eat foods at home—refrigerated or not—has led to higher risks of the bacteria Listeria monocytogenes in cooked products,” said Rubio.

Listeria monocytogenes can tolerate high concentrations of salt and sodium nitrate, food additives used in ready-to-eat products. Currently, the Alaska seafood industry uses a salt water brine and water glaze to protect crab meat. Rubio is evaluating the ability of the chitosan coating to inhibit the bacteria in Dungeness crab products, possibly expanding the market and extending shelf life.

Alaska Sea Grant seafood specialists Chris Sannito and Quentin Fong are helping Rubio with equipment, supplies and logistics at the Kodiak Center, and ASMI seafood technical director Michael Kohan is supervising the project.

Rubio, who is from Ecuador, is a PhD graduate student at Louisiana State University where she studies food microbiology. She earned her master’s in poultry nutrition. “When I got my master’s degree I decided to change my concentration to food microbiology in order to have a complete understanding of the food industry,” she said.

Rubio is enjoying her three-month stay in Kodiak, where she has gone hiking and appreciates the beautiful scenery. “Pasagshak Bay is for me the most gorgeous place of Kodiak. I am very lucky this summer—the weather is amazing,” she said.