Knowing how to cook with spices is an important skill in any cook’s culinary arsenal. However, some of those seasonings might eventually be used as components in literal cooking tools as well: researchers recently used curcumin, the compound that gives turmeric its bright yellow coloring, to create a food-safe antibacterial surface that kills bacteria on contact. This development could lead to cutting boards, cleavers, countertops and other kitchen implements that actively prevent contamination as food is being prepared.
Cross-contamination is a major problem in the food industry, causing bacteria to spread around the kitchen and potentially making dozens of people sick. But while antimicrobial technology has been used to make everything from odor-free socks to self-cleaning toilet seats, the germicides typically found in these products are not generally recognized as safe for food production.
Because of this, a research team at South Illinois University, Carbondale decided to create an antibacterial surface from food-grade materials. They began by screening 11 natural food compounds with known antimicrobial properties, such as resveratrol from grapes and hydroxytyrosol from olives. However, their tests showed that curcumin was the most effective at curbing E. coli growth.
Next, the researchers packed curcumin inside custom-built nanovesicles, which consisted of a membrane bilayer made from diacetylene fatty acids and a phospholipid, known as the fundamental building block of a cellular membrane. These nanovesicles were then attached to glass with N-hydroxysuccinimide groups and glucose molecules, forming a surface that would attract passing bacteria. The research team then compared glass slides coated with the curcumin nanovesicles to those without this additive. They found that less than 0.5% of the bacteria survived when the slides with curcumin were immersed in flasks spiked with E. coli for 48 hours, while no significant decline occurred in the non-curcumin slides.
Interestingly, the success of the curcumin nanovesicles is still somewhat of a mystery, even to the researchers. The team has pointed out that curcumin tends to cohere within the bilayer more than in the vesicle’s central space, hypothesizing that the compound migrates into the cell wall of a passing bacterium when the molecule attaches to the vesicle’s surface and kills it from the inside. But while the particular details are still unclear, the antimicrobial properties of the spice are clearly responsible for the product’s success.
Despite the early promise of the curcumin surface, a number of challenges await the researchers if their product is to be used for commercial use. Experts have commented that the team will need to prove that the antimicrobial surface works long-term, does not transfer an odor or taste to the food, does not shed nanoparticles, and can fight the resistant biofilms that form on food processing equipment. As a result, the team is currently testing whether or not the active surface blocks biofilm formation.