Evaluation of antimicrobial effect of Commercial Norbixin pigment (Bixa orellana L.) against pathogenic bacteria and food spoilage in vitro

Norbixin is the water-soluble part of anatto natural pigment which has healing, anti-cancer and antioxidant properties. The aim of this study was to evaluate the antimicrobial effect of commercial Norbixin 1% (widely used in the food industry) on Clostridium sporogenes, Staphylococcus aureus, Listeria monocytogenes, Escherichia coli, Salmonella typhimurium and Bacillus licheniformis. In this study, two methods of Well diffusion and Disk diffusion were used to evaluate the antimicrobial effect of Norbixin (1%) at concentrations of 2, 4, 6 and 8%. The results of the Well method showed that Staphylococcus aureus with 22.74 mm and Clostridium sporogenes with 14.44 mm have revealed the highest and lowest sensitivity, respectively. The results of Disk method showed that the highest mean diameter of Norbixin inhibitory in all tested concentrations is attributed to Listeria monocytogenes with mean diameter of 19.09 mm and then is related Staphylococcus aureus at a concentration of 4% with a diameter of 18.21 mm. It was also observed that in the Disk diffusion method, Norbixin was able to prevent the growth of Escherichia coli (9.09 mm) at concentrations of 4 and 8%. Accordingly, it was found that Norbixin has an inhibitory effect on both gram-positive and gram-negative bacteria, and this effect on gram-positive bacteria was more than gram-negative. Therefore, due to the disadvantages of synthetic preservatives and the unique properties of commercial Norbixin pigments such as natural and safe, having antimicrobial and therapeutic properties as well as good thermal resistance (because of apocarotenoid structure during processing), this pigment can be used as a natural antibacterial preservative and health-giving properties in various foods.