Investigating the inhibitory effects of free and encapsulated curcumin on foodborne pathogens -

Abstract

Tahini-based products are common food items throughout the Middle East while gaining popularity around the world. Consumption of such products both locally and internationally requires that they meet food safety standards along with an acceptable shelf-life. Over the past few years, several outbreaks associated with tahini-based products have been reported as well as product recalls due to confirmed contamination with Salmonella spp., Listeria monocytogenes, Escherichia coli or Staphylococcus aureus. Various preservation techniques have been used including chemical and thermal processing to insure the safety of such products. However, treating tahini and tahini-based products using such methods alters the texture and quality of the final product. Moreover, given the public’s growing concerns regarding the use of chemical preservatives, there has been an increased interest to explore natural additives that may contribute to preserving the quality and safety of the final product. Such natural ingredients include spices some of which have already proven to possess antimicrobial effects. Curcumin, the bioactive component of turmeric, is a natural spice that has been shown to possess a wide range of anti-microbial, anti-fungal as well as anti-cancer activities when tested both in-vitro and in-vivo. To the best of the authors’ knowledge, no studies have been conducted to study the antimicrobial effect of curcumin on foodborne pathogens. Accordingly, this study aims to investigate the anti-microbial effect of Curcumin preparations, both free and encapsulated in liposomes, against Salmonella spp., E. coli, Listeria monocytogenes and Staphylococcus aureus. Based on the results of the microbiological tests, curcumin in both forms (free and encapsulated) showed no effect on the foodborne pathogens under consideration in this study with gram-negative bacteria being more resistant than gram-positive bacteria attributed to the difference in the membrane structure of these microorganism.