Microbiological assay for chloramphenicol residues.

Area of Science:

• Analytical Chemistry
• Food Safety
• Veterinary Science

Background:

• Chloramphenicol is an antibiotic used in food-producing animals, but its residues are a public health concern due to potential toxicity.
• Accurate and sensitive detection methods are crucial for monitoring chloramphenicol residues in animal-derived products and biological matrices.

Purpose of the Study:

• To develop and validate a highly sensitive and reliable assay for quantifying chloramphenicol residues.
• To establish standardized procedures for chloramphenicol detection in milk, urine, serum, and muscle tissue.

Main Methods:

• The assay incorporates specific design elements: simultaneous presence of standards and samples on each plate, inclusion of oxytetracycline for enhanced sensitivity, a minimal medium to amplify chloramphenicol's inhibitory effect, and tetrazolium dye for improved measurement of inhibition zones.
• Validated for various matrices including bovine urine, serum, milk, and swine, beef, and chicken muscle tissue.

Main Results:

• High recovery rates of unbound chloramphenicol were achieved: 90.8% in bovine urine, 88.3% in serum, 79.3% in milk, 71.3% in swine muscle, and 61.0-61.4% in beef and chicken muscle.
• Established lower levels of measurement: 0.25 µg/mL in urine and serum, 0.025 µg/mL in milk, and 0.10 µg/g in muscle tissue.

Conclusions:

• The presented assay provides a sensitive and robust method for chloramphenicol residue analysis in diverse biological and food matrices.
• This optimized procedure is valuable for regulatory compliance, veterinary diagnostics, and ensuring food safety by detecting illegal antibiotic use.