Relevance of Isotopic and Molecular Biomarkers for the Authentication of Milk According to Production Zone and Type of Feeding of the Cow

Abstract

The first objective of the present paper was to assess the potential of both isotopic ( (18)O/ (16)O in milk water) and molecular biomarkers (terpenes, fatty acids, carotenoids, and vitamins) and milk color to discriminate the production zone (lowland or upland areas) from which 49 tanker bulk milks were collected over one year from a total of 204 farms. The milk water (18)O enrichment was higher in lowland (<500 m altitude) than in upland (>700 m altitude), but the delta (18)O values failed to discriminate systematically the production zone at the scale of the year because of its high variability related to the sampling period. In contrast with vitamins A and E, carotenoids, and milk color measurements, terpenes and fatty acids were confirmed to be relevant tracers of the production zone. The milk compounds with the strongest discriminative potential were fatty acids, which were determined by high-resolution gas chromatography. The calculation of fatty acid ratios, which permits the limitation of using fatty acid relative quantity expressed in percentage of total fatty acids to be overcome, was shown to be particularly relevant in discriminating upland from lowland milk ratios. The selection of two pairs of ratios, namely, iso-C17:0/C18:3 n-3 and iso-C15:0/iso-C14:0, enabled the authentication of 100% of the highland versus lowland milks whatever the season. The second objective was to evaluate the relevance of fatty acid composition to discriminate milks according to the proportion of corn silage in the diets of dairy cows. The selection of two fatty acids ratios, namely, trans11 cis15-C18:2/trans11-C18:1 and cis9-C16:1/iso-C16:0, enabled the correct classification of 100% of the milk samples according to the proportion of corn silage in the basic fodder rations (<25% vs >30%). The relationship between the milk production zone and the type of forage fed to the cows is discussed.

Stable isotope ratios of blood components and muscle to trace dietary changes in lambs

“…Similar results were previously observed by Perini et al (2009) in an overview on lambs from different Italian production systems. An increase in the d 18 O value due to a diet based on fresh forages compared with preserved forages has also been observed in cow milk water fraction (Kornexl et al, 1997;Renou et al, 2004a;Engel et al, 2007) and in beef meat water fraction (Boner and Fö rstel, 2004;Renou et al, 2004b).…”

H, C, N and O stable isotope characteristics of alpine forage, milk and cheese

“…O can distinguish between milk produced in different areas (Chesson et al, 2010;Crittenden et al, 2007;Engel et al, 2007 (Kornexl et al, 1997;Renou et al, 2004). (Camin et al, 2008) and they can therefore be used to discriminate between regions (Pillonel et al, 2003), as also observed for meat proteins (Camin et al, 2007;Heaton, Kelly, Hoogewerff, & Woolfe, 2008;Perini et al, 2009).…”

“…As the isotopic ratios of diet constituents and water are related to local environment, isotope ratio analysis has recently been used to discriminate between milk and cheese produced in different areas, with different dietary regimes and production systems (organic or conventional) (Brescia, Monfreda, Buccolieri, & Carrino, 2005;Bontempo et al, 2011;Camin et al, 2004;Chesson et al, 2010;Crittenden et al, 2007;Engel et al, 2007;Kornexl, Werner, Rossmann, & Schmidt, 1997;Manca et al, 2001Manca et al, , 2006Molkentin, 2009;Molkentin & Giesemann, 2007;Pillonel et al, 2003;Renou et al, 2004). C isotope ratio (expressed as d 13 C) of milk and cheese components is related to the quantity of maize, which is an important constituent of cows' diet in many countries, especially in intensive breeding systems, but is often also used for energy supplementation in other dairy systems.…”

Variation in fatty acid composition of milk and cheese from cows grazed on two alpine pastures

“…Beyond the human health effects, FA profiling is a useful tool, when used singly or in combination with other methods, for milk and cheese quality and tracing their origin [17], and to verify product authenticity.…”