Impact of Thymus vulgaris Extract with Nano Chitosan in preserving beef meat contaminated with Staphylococcus aureus and Escherichia coli O157:H7

Abstract

Beef is one of the most consumed types of food in many countries, whether local or imported, which requires attention to its quality and health safety. Meat and its products contaminated by various types of bacteria which are regarded as a critical concern globally due to their significant role in foodborne illnesses and zoonotic diseases. This research aims to focus on isolating and identifying bacteria S. aureus and E.coli O157:H7 found in local beef meat and investigate the effect of Thymus vulgaris extract, Chitosan nanoparticles and Chitosan nanoparticles loaded with Thymus vulgaris on preserving meat from microbial spoilage due to study the bacterial load and other quality parameters of beef meat under refrigerator temperature at different times 0, 2, 5, 7 and 10 days of storage. This work was carried out from January to October 2025. A total of 100 beef meat samples were collected and cultured on specialized media to isolate and identify bacteria and confirm using the polymerase chain reaction (PCR) method to detect S. aureus and E. coli O157:H7. The results of this study identified S. aureus in 20 out of 100 (20%) beef meat samples collected, while identified Escherichia coli O157:H7 in 13 out of 100 (13%) beef meat samples collected. Thymus extract and Chitosan nanoparticles demonstrated high effectiveness in preserving the quality of meat during significantly (p ≤ 0.05) reduced the total bacterial count, stabilized pH values within normal limits. Also, reduced the Thio barbituric acid reductase levels. In conclusion, Thymus vulgaris extract and Chitosan nanoparticles have ability to inhibit the growth of (S. aureus and E. coli O157:H7) and reflecting their role as effective antioxidants. Also, the ability to preserve the meat at refrigerator temperature.