Heat stable inhibitors produced in raw milk

Area of Science:

• Food Science
• Microbiology
• Analytical Chemistry

Background:

• Raw milk quality is crucial for dairy products.
• Storage conditions can alter milk composition and introduce contaminants.
• Detection of inhibitory substances is vital for milk safety.

Purpose of the Study:

• To investigate the presence of inhibitory substances in raw farm milk.
• To evaluate the impact of temperature and pH changes on inhibitor formation.
• To compare the efficacy of different detection methods.

Main Methods:

• Testing twenty raw farm milk samples.
• Storing samples until pH reached 6.2-6.3.
• Utilizing the IDF-method and Thermocult method for detection.
• Employing Bacillus stearothermophilus var. chalidolactis as the test organism.

Main Results:

• Two samples produced thermostable inhibitors.
• Inhibitory potential exceeded 0.01 IU/ml penicillin standard in positive cases.
• The IDF-method demonstrated limitations in detecting low concentrations of antibiotics.

Conclusions:

• Raw milk can generate thermostable inhibitors under specific storage conditions.
• The Thermocult method showed potential for detecting these inhibitors.
• Further research is needed to refine methods for detecting low-level inhibitors in milk.