Evaluation of the Delvo-X-Press assay for detecting antibiotic residues in milk samples from individual cows

Apostolos S. Angelidis, Thomas B Farver, James S Cullor

Research output: Contribution to journalArticle

13 Scopus citations

Abstract

Performance of the Delvo-X-Press β-lactam antibiotic assay was examined using bulk-tank milk samples and milk samples from individual cows. Bulk-tank milk samples fortified with bovine lactoferrin at a concentration of 1 mg/ml or more consistently tested positive. False-positive results were also obtained from bulk-tank milk samples fortified with bovine plasma at concentrations of 20 and 40%. The assay yielded positive results for milk with antibiotic concentrations as low as 2 ppb. Individual milk samples were collected from 144 healthy lactating cows and from 34 cows with chronic Staphylococcus aureus mastiffs. Specificity estimates for samples from healthy and mastitic cows were 0.88 (95% confidence interval [CI], 0.82, 0.93) and 0.94 (95% CI, 0.86, 1.00), respectively. Individual milk samples were collected from three cows with experimentally induced mastitis for 21 consecutive days. False-positive results occurred as late as 12 days postchallenge. A moderate but significant (P < 0.01) positive linear correlation (r = 0.61) was observed between test result and somatic cell count (SCC) values in milk samples with SCCs of >106/ml.

Original languageEnglish (US)
Pages (from-to)1183-1190
Number of pages8
JournalJournal of Food Protection
Volume62
Issue number10
StatePublished - Oct 1999

ASJC Scopus subject areas

  • Food Science
  • Applied Microbiology and Biotechnology
  • Biotechnology

Fingerprint Dive into the research topics of 'Evaluation of the Delvo-X-Press assay for detecting antibiotic residues in milk samples from individual cows'. Together they form a unique fingerprint.

  • Cite this