Be. Kornexl et al., MEASUREMENT OF STABLE-ISOTOPE ABUNDANCES IN MILK AND MILK INGREDIENTS- A POSSIBLE TOOL FOR ORIGIN ASSIGNMENT AND QUALITY-CONTROL, ZEITSCHRIFT FUR LEBENSMITTEL-UNTERSUCHUNG UND-FORSCHUNG A-FOOD RESEARCH AND TECHNOLOGY, 205(1), 1997, pp. 19-24
Relative carbon and nitrogen stable isotope abundances in total milk r
eflect the isotopic composition of the diet fed to the dairy cows; thi
s diet and its delta-values depend on geographical and climatic factor
s. Milk from regions dominated by grassland typically shows relatively
negative delta(13)C-values, while in regions dominated by crop cultiv
ation the delta(13)C-values are more positive. The delta(15)N-values a
re influenced by factors such as soil conditions, the intensity of agr
icultural use and the climate. Casein in authentic milk samples is enr
iched in both C-13 and N-15 as compared to total milk, while the whey
fraction is slightly enriched in C-13 and depleted of N-15. Th, isotop
ic content of milk, casein and whey from one location have been measur
ed throughout a period of longer than 1 year; variations are usually n
ot greater than 1 parts per thousand. In milk water, the O-18 content
was increased by between 2 and 6 parts per thousand as compared to gro
und water.