Abstract
Background:
Meat has been regarded as a very healthy food because of its nutritional value; minced meat is a popular meal; however, microbial contamination may have negative impacts on meat quality and consumer health.

Aim:
The study aimed to estimate the bacteriological contamination and use of some chemical and natural preservatives in minced meat.

Methods:
Approximately 103 samples of minced meat were collected from different butchers in Al-Najaf province from December 2024 to March 2025 to monitor their microbiological quality. Biochemical and polymerase chain reaction techniques for 16S rRNA gene amplification were used to confirm the bacterial identity, and the effects of lactic acid (3%), rosemary volatile oil (2%), thyme oil (1.5%), and the combination of thyme (1.5%) and rosemary (2%) were used as antibacterial after immersing the samples with these substances following bacterial counts.

Results:
Total coliforms, Escherichia coli, and Staphylococcus aureus were 70%, 58%, and 54%, respectively. Furthermore, the mean values of average bacterial counts of total coliform, E. coli, and S. aureus were 4.35, 3.73, and 3.43 CFU log10/g, respectively. Compared with the control, statistically significant differences (p < 0.05) were observed between the single and combination use of substances and lactic acid. The combination of rosemary and thyme was the most effective, resulting in a reduction of coliform, E. coli, and S. aureus (1.11, 1.95, and 1.42 CFU, respectively) after 7 days.

Conclusion:
The high levels of contamination detected in the minced meat are an indication of unhygienic production conditions, and the synergistic activity of rosemary and thyme was most effective in reducing contamination.

Key words: Contamination; E. coli; Essential oil; Minced meat; S. aureus.