Antimicrobial Properties of CMC-based Edible Films Incorporated with Coriander and Citrus Lemon Essential oils on the Shelf-life of Fresh Lamb-meat at Refrigerator Temperature

Microbial spoilage of meat and meat products leads to the development of off-odors, tissue breakdown, economic damages, and toxic effects to humans. The objective of this study was to assess the microbial properties and efficacy of coriander and lemon oils incorporated with carboxymethyl-cellulose (CMC) to minimize the presence of pathogenic-bacteria in lamb meat. CMC films containing coriander and lemon oil (0, 0.1, 0.2, 0.3 and 0.4%v/v film solution) were prepared. Antimicrobial properties of the films were investigated on Staphylococcus-aureus, Escherichia coli, and Pseudomonas-aeruginosa on agar medium. CMC films with 0.4% essence or without essence were wrapped around the meats and stored at 4±1°C for 8 days. The coated and uncoated samples were analyzed periodically to determine microbiological properties (total bacteria count, Coliform, Staphylococcus.spp and Pseudomonas.spp) and pH. Both films containing essence had antimicrobial effects on the nutrient-agar medium against the Escherichiacoli and Pseudomonas-aeruginosa, while they had no anti-microbial effects on Staphylococcus-aureus. As compared with the control samples, significant decrease was observed in total count bacteria, coliform, Staphylococcus.spp and Pseudomonas.spp in lamb meat samples treated with CMC films (p<0.05). The anti-microbial effect of lemon oils on Pseudomonas.spp was significantly greater than coriander. The CMC films with or without essence caused a decrease in pH of the meat samples. The CMC films enriched with essence, especially lemon essence, delayed tissue breakdown, and increases the pH by reducing the bacterial growth. Therefore, use of citrus lemon film as an economical and biodegradable coating has a good potential for increasing the shelf-life of lamb meat at the refrigerator temperature.