Like a wolf in sheep's clothing, the compound mimics the structure of the molecules that form bacterial membranes, which also have water-repulsing residues on the outside, but it may disrupt those membranes by forming a rigid pore.

"The protein seems perfectly engineered to kill competing bacteria," said Worobo.

This strain is effective against several strains of Bacillus, Listeria and Carnobacterium that cause food-borne disease or spoilage in food kept at improper temperatures and raw milk.

Now, Worobo and Vederas are exploring these unusual linkages and are working to characterize the mode of action of this unique peptide, with the goal of developing thurincin H as an alternative to synthetic food preservatives.

"Bacteriocins are promising natural food preservatives for the food, livestock and agricultural industries," said Worobo. "Because they come from food-grade microorganisms, they are generally regarded as safe."