Analysis of oxytocin in milk samples and intake pattern in different age groups of Indian population

Abstract

Background: Oxytocin (OT) injections have been indiscriminately used to milk cattle in dairy industries. There is no study available regarding surveillance of OT in market milk samples.

Material and methods: OT from milk samples was extracted by precipitation with trichloroacetic acid and passed through the solid phase extraction column. OT was eluted and evaporated to dryness under a gentle stream of nitrogen. The residue was either dissolved in milli Q water or buffer for analysis through HPLC or EIA. The intake assessment of OT through milk was assessed through the Food Frequency Recall method employing a Food Frequency Questionnaire. On the basis of milk consumption and the values of OT in milk, the actual intake of OT was calculated.

Results: In the present study, a total of 55 milk samples (39 milkman and 16 branded) were analyzed for occurrence of OT by EIA and UV-HPLC from different locations of Lucknow, Uttar Pradesh (India). OT contamination in milkman samples was found to be 21 pg/mL to 18.9 ng/mL with the mean value of 8.9 ng/mL. The average daily intake of OT in terms of µg/day/person was highest (2.3–2.4 µg/day/person) in 1–3-year age group.

Conclusions: Since there is no prescribed level of OT in milk and the intake of OT through this commodity is quite high there is need to implement regulatory laws so that non-physiological OT exposure may not occur in children which may have deleterious effects.

• Enzyme immunoassay
• high-performance liquid chromatography
• milk
• oxytocin
• SPE column

Acknowledgements

We are grateful to the Director of our Institute for his keen interest in this present study. M.M. is thankful to Council of Scientific and Industrial Research (CSIR), New Delhi for the award of Senior Research Fellowship. Financial assistance of CSIR- INDEPTH Project- BSC-0111 is gratefully acknowledged. The manuscript is IITR communication # 3051.