Pathogenic bacteria in cheese, raw and pasteurised milk.

Area of Science:

• Food safety and microbiology
• Molecular diagnostics
• Public health

Background:

• Foodborne diseases from milk and dairy products pose a global health challenge.
• Increasing antibiotic resistance in bacteria like Listeria monocytogenes, Staphylococcus aureus, and Salmonella typhi complicates infection control.
• Antibiotic residues in animal products are a growing concern.

Purpose of the Study:

• To assess contamination levels of raw milk, pasteurized milk, and local cheese with specific foodborne pathogens.
• To develop and evaluate a rapid Multiplex PCR method for detecting these contaminants.
• To determine the antibiotic resistance patterns of isolated bacteria.

Main Methods:

• Collected 100 samples from livestock and retail outlets.
• Utilized culture and molecular methods (real-time qPCR, Multiplex PCR) for bacterial identification.
• Determined antibiotic resistance profiles of identified isolates.

Main Results:

• Culture methods detected Staphylococcus aureus in 10% of samples; Salmonella typhi and Listeria monocytogenes were undetected.
• Real-time qPCR identified Staphylococcus aureus in 60%, Salmonella typhi in 53%, and Listeria monocytogenes in 2% of samples.
• Multiplex PCR showed 72% specificity and 80% sensitivity, deemed unreliable for rapid diagnosis.

Conclusions:

• Real-time qPCR is a highly sensitive method for detecting Staphylococcus typhi, Listeria monocytogenes, and Staphylococcus aureus in milk products compared to traditional culture.
• The Multiplex PCR method demonstrated insufficient reliability for rapid and accurate diagnosis of these foodborne pathogens.
• Further research into sensitive and reliable molecular diagnostic tools is crucial for ensuring milk and dairy product safety.