A Practical Sensitive Test to Detect Penicillin in Milk

Area of Science:

• Food Science
• Microbiology
• Analytical Chemistry

Background:

• Penicillin contamination in milk poses a public health risk.
• Accurate and rapid detection methods are crucial for milk quality control.
• Existing methods may lack sensitivity or speed.

Purpose of the Study:

• To modify and optimize the International Dairy Federation (IDF) disc assay for penicillin determination in milk.
• To enhance the sensitivity and reduce the assay time for penicillin detection.
• To provide a reliable method for ensuring milk safety and quality.

Main Methods:

• Modification of the standard IDF disc assay protocol.
• Optimization of seed broth preparation, seeded plate creation, and standard solution formulation.
• Incubation of plates at 55°C for 4 hours.

Main Results:

• The modified assay demonstrated high sensitivity in detecting penicillin.
• Detection limits of approximately 0.004 units/ml were achieved with stored plates.
• As low as 0.002 units/ml penicillin could be detected using freshly prepared materials.

Conclusions:

• The modified disc assay is a sensitive and rapid method for penicillin detection in milk.
• This optimized assay can effectively ensure the safety and quality of milk supplies.
• The method provides a valuable tool for regulatory agencies and the dairy industry.