Multiresidue screening of milk withheld for sale at dairy farms in central New York State

Richard Van Vleck Pereira, J. D. Siler, R. C. Bicalho, L. D. Warnick

Research output: Contribution to journalArticlepeer-review

33 Scopus citations


Many of the drugs commonly used in lactating dairy cows result in residues in the milk, prohibiting its sale for human consumption. Milk withheld for sale because of drug treatment or from cows with high somatic cell counts is commonly called "waste milk." One-third of dairy farms in the United States use waste milk to feed preweaned dairy calves. Limited information is currently available on the effect of this practice on the selection and dissemination of antibiotic-resistant bacteria. Pooled waste milk samples were collected from 34 dairy farms in central New York State with the objective of detecting the presence and quantity of drug residues in these samples. Samples were collected and refrigerated using ice packs and then stored at 4°C upon arrival at the Cornell laboratory (Ithaca, NY). Screening for β-lactam, tetracycline, and sulfonamide residues in the milk was performed using commercial enzyme-linked receptor-binding assay (SNAP) tests (Idexx Laboratories Inc., Westbrook, ME). Samples with a positive SNAP test were selected for screening using a multiresidue liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. The SNAP tests revealed that 75, 14.3, and 7.1% of waste milk samples (n. = 34) contained β-lactam, tetracycline, and sulfamethazine residues, respectively. Of the samples sent for LC-MS/MS (n. = 28), half had detectable quantities of drug residues. The most prevalent drugs detected by LC-MS/MS were ceftiofur (39.2%; mean ± SE concentration. = 0.151. ±. 0.042. μg/mL), penicillin G (14.2%; mean ± SE concentration. = 0.008. ±. 0.001. μg/mL), and ampicillin (7.1%; mean ± SE concentration. = 0.472. ±. 0.43. μg/mL). In addition, one sample had detectable concentrations of oxytetracycline and one sample had detectable concentrations of sulfadimethoxine. These results provide insight on drug residues present in waste milk from select farm in upstate New York, and additionally indicate the need for additional studies targeting on-farm treatments that could degrade drug residues present in waste milk and reduce the potential effects on the biosphere from the disposal and use of waste milk as a feed source.

Original languageEnglish (US)
Pages (from-to)1513-1519
Number of pages7
JournalJournal of Dairy Science
Issue number3
StatePublished - Mar 2014
Externally publishedYes


  • Antibiotic resistance
  • Drug residues
  • Liquid chromatography-tandem mass spectrometry
  • Waste milk

ASJC Scopus subject areas

  • Animal Science and Zoology
  • Food Science
  • Genetics
  • Medicine(all)


Dive into the research topics of 'Multiresidue screening of milk withheld for sale at dairy farms in central New York State'. Together they form a unique fingerprint.

Cite this