Activity of Binary Combinations of Natural Phenolics and Synthetic Food Preservatives against Food Spoilage Yeasts.

Natural compounds are a suitable alternative to synthetic food preservatives due to their natural origin and health-promoting properties. In the current study, phenolic-phenolic and phenolic-synthetic combinations were tested for their antibiofilm formation, anti-planktonic growth, and anti-adhesion properties against Debaryomyces hansenii , Wickerhamomyces anomalus (formerly Pichia anomala ), Schizosaccharomyces pombe , and Saccharomyces cerevisiae . The phenolics were vanillin and cinnamic acid, while the synthetic preservatives were sodium benzoate, potassium sorbate, and sodium diacetate. The vanillin-cinnamic acid combination had synergistic effect in all the tested yeasts for the biofilm inhibition with a fractional inhibitory concentration index (FICI) of ≤0.19 for W. anomalus , 0.25 for S. pombe , 0.31 for S . cerevisiae , and 0.5 for D. hansenii . Most of the phenolic-synthetic combinations had indifferent interaction regarding biofilm formation. The vanillin-cinnamic acid combination also had higher activity against spoilage yeasts adhesion on the abiotic surface and planktonic growth compared to the phenolic-synthetic combinations. For the phenolic-synthetic anti-planktonic activity, synergistic interaction was present in all the vanillin-synthetic combinations in S. pombe , vanillin-sodium benzoate and vanillin-potassium sorbate in S. cerevisiae , vanillin-sodium benzoate in W. anomalus , and cinnamic acid-sodium diacetate in S. pombe . These results suggest a novel antimicrobial strategy that may broaden the antimicrobial spectrum and reduce compound toxicity against food spoilage yeasts.