Evaluation of the Antimicrobial Effects of Laurus nobilis leaf Extract as a Fresh Meat Preservative

Abstract

Fresh red meats especially sheep meats, by their nature are nutritious and easily metabolisable and therefore offer suitable substrates for the growth and metabolism of microorganisms. Foodborne disease is a cluster of microbial or toxic gastrointestinal diseases, which results from consuming contaminated food with certain microbial agents or their toxins. Prevention of food spoilage and food poisoning pathogens is usually achieved by the use of chemical preservatives which have negative effects on human health. The purpose of this thesis is to find a potentially valuable, healthy safer and natural alternative preservative. The objectives of present work are concentrated on the screening of sheep meat samples for the presence of lipid food poisoning bacteria, investigating the antimicrobial activity of Laurus nobilis extracts against lipid food poisoning bacteria, and detecting the duration that can the fatty food be preserved by antioxidant and antimicrobial action of Laurus nobilis leaf. Samples of sheep meat were collected and bacterial 2 contaminants were isolated and identified by specific biochemical techniques, and sequence of the 16SrRNA gene. Antimicrobial activity of Laurus nobilis extract was investigated against all isolates using agar well diffusion technique. Thirty four bacterial isolates were isolated and identified. Methanol extraction of Laurus nobilis leaves produced the maximum essential oil yield than ethanol extraction. Gram-positive isolates were more affected by antimicrobial effect of Laurus nobilis extract than gram-negative isolates. In addition, Laurus nobilis extract has the ability to increase the shelf-life of sheep meat to 13 days with accepted features at refrigerator, and to three days at room temperature by using spraying method. The thesis results showed that Laurel extract has the potential to be used as natural alternative preventive to control food poisoning diseases and preserve foodstuff avoiding health hazards of chemically antimicrobial agent applications.