Improved microbiological procedure for determining bacitracin in premixes and mixed feeds

Area of Science:

• Microbiology
• Analytical Chemistry
• Animal Nutrition

Background:

• Bacitracin is a crucial antibiotic used in animal feed for growth promotion and disease prevention.
• Accurate quantification of bacitracin in feed premixes and mixed feeds is essential for regulatory compliance and animal health.
• Existing methods for bacitracin determination can be complex and time-consuming.

Purpose of the Study:

• To develop and validate an improved microbiological procedure for determining bacitracin content.
• To simplify the extraction and assay process for bacitracin in animal feed matrices.
• To ensure the accuracy and repeatability of the new method compared to official standards.

Main Methods:

• Premixes extracted with acidic 50% aqueous methanol; mixed feeds extracted with 50% dimethylformamide after acetone washing.
• Extracts diluted with pH 6.0 phosphate buffer.
• Assay performed using a 2-point assay system with Micrococcus flavus as the test organism.

Main Results:

• The improved method successfully determined bacitracin levels as low as 10 g/ton.
• The simpler extraction procedure enhanced efficiency.
• The 2-point assay system demonstrated accuracy and repeatability comparable to official AOAC methods.

Conclusions:

• The presented microbiological procedure offers a simpler and effective method for bacitracin quantification in feed premixes and mixed feeds.
• The method's sensitivity and reliability make it suitable for routine analysis.
• This approach provides a valuable alternative to existing official methods for bacitracin analysis.