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Access Type

WSU Access

Date of Award

January 2017

Degree Type

Dissertation

Degree Name

Ph.D.

Department

Nutrition and Food Science

First Advisor

Ahmad Heydari

Abstract

Meat is highly perishable food since it contains sufficient nutrients needed to support the growth of microorganisms which is effect of nutritional value and spoilage of meat. There are many methods are available to control food pathogens in meat. Using natural antimicrobial may be is a good option because it is provide many benefits. This study showed the synergistic effect of individual and combinations of lactoferrin, lysozyme and nisin in-vitro and in-vivo (in meat) had significant effect (P < 0.05) on reducing the number of foodborne pathogens in meat. Toxigenic Staphylococcus aureus contamination in meat is a major problem in public health due to the production of heat-stable enterotoxins. Also, S.aureus expresses an many array of virulence factors contribute to the ability of S. aureus to cause infection, our results showed that high percentage (42.9) of S. aureus in meat and 80.9 % of S. aureus isolates contained at least one enterotoxin gene. The three most common enterotoxin genes in meat were sea gene (61.9%) followed by seh gene (33.3%) and sei gene (30.1). Some of S. aureus isolates contained more than one enterotoxin gene. In addition, our results indicated that S. aureus isolates from meat showed different antimicrobial resistance levels against fourteen antibiotics. Also, S. aureus multidrug resistant were high in meat. There are different types of meat based on the meat production method. Halal meat is produced without stunning prior to slaughter, resulting in a rapid and complete bleeding of animals. Our results showed that halal meat production method resulted in significantly lower residual heme iron than conventional method with stunning (non-halal method). Microbiological analyses of fresh meat samples showed that halal meat production method had significantly lower (P < 0.05) microbial count than non-halal meat method. Storage of meat is critical because during storage even with proper refrigeration, the meat ultimately undergoes deteriorative changes including microbial spoilage, oxidative changes. Our results indicated that meat production method significantly affects the meat quality not only for fresh meat but also during storage. Microbiological analyses of meat samples during storage for three weeks at 4°C showed that halal meat method had significantly lower (P < 0.05) microbial count than non-halal meat. Physiochemical analyses showed that quality indicators for meat such as lipid oxidation, drip loss, pH, and heme iron content were significantly lower (P < 0.05) in halal meat than non-halal meat during storage. Halal meat processing may be advantageous in reducing bacterial colonization, increasing the usable shelf life, and improving the quality of the fresh and stored meat.

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