Study On The Tracing Technology Of Beef By Stable Isotopes

Stable isotope technology was applied in the fields of geology, archeology, medical and environmental science in early time. In recent years, stable isotope analysis is applied in the traceability of food geographical origin thanks to its virtue. The objective of this article was to push forward its application and development into food science and it was studied in beef traceability.In order to research on different stable isotope composition in the different beef tissues, as well as the breed, longissimus muscle, psoas major muscle, leg muscle, buttock muscle, cattle tail hair, blood, liver and feed were collected, which were belonging to simmental and charolais cattle under the same culture conditions. Theδ¹³C,δ¹⁵N,δ²H,δ³⁴S values of above tissues,andδ²H,δ¹⁸O of muscle tissue water were determined using isotope ratio mass spectrometry(IRMS). Then the data were performed using multivariate analysis including ANOVA with the help of SAS Package for windows. The results showed thatδ¹³C,δ¹⁵N,δ³⁴S values of cattle tissues exceptδ²H values were not different between breed. Theδ¹³C values of crude fat were far lower than those of other tissues, but it had not significant difference between different fat sources and the same as other defatted tissues (P>0.05). However,δ¹⁵N values of defatted liver, andδ²H,δ³⁴S values of cattle tail hair were significantly higher than those of muscle tissues (P<0.01). So these results indicated that isotope fractionation in the various tissue was discrepant. Theδ²H andδ¹⁸O values of muscle tissue water were positively correlated (R2=0.83, P<0.01 ), but these values varied in a large range. Theδ¹³C,δ¹⁵N,δ³⁴S,δ²H values between each tissue were not significantly correlated, so the proper tissue or component should be selected according to the purpose and object in the beef traceability study.Previous studies had shown that the stable carbon and nitrogen composition of diets influenced theδ¹³C andδ¹⁵N values of animal tissue. 36 (12 to14 months old) young bulls were selected and assigned to 2 large groups fed with a diet consisting of different content of C3,C4 plant with the aim of developing a quantitative relationship between the dietary C4 and C3 plant intake andδ¹³C of bovine tissues. All animals were slaughtered after feeding for 132 days. Theδ¹³C andδ¹⁵N values of cattle tail hair, defatted muscle, crude fat and each feed material were determined by isotope ratio mass spectrometry (IRMS). It was shown that the stable carbon isotope composition of beef tissue was primarily dependent on the diet the animals were fed,meanwhile theδ¹³C values of cattle tail hair, defatted muscle and crude fat all enhanced with the increment of the proportions of C4 constituents in diet, but those values were on the contrary with the enhancement of the proportions of C3 constituents. Moreover, allδ¹³C values of different tissues were significantly correlated with the content of C4 and C3 plant material. So, the main component of cattle feed could be investigated with the help ofδ¹³C values. Theδ¹⁵N values of beef tissues were affected by feed composition to some extent, but it had no regularity. The cattle tail hair and defatted muscle enriched in 13C to their feeds gave different results between the two groups, but cattle tail hair enriched in 15N much more than defatted muscle and in the proportion of 3‰- 5‰, plus, cattle variety and individual had effect on the proportion of enrichment. Theδ¹³C values between cattle tail hair, defatted muscle, crude fat were significantly correlated (P< 0.01), which suggested that all of them could be used for beef traceability.For exploring the feasibility of stable isotope technique for cattle geographical origin, the beef samples and drinking water samples were collected from different regions, then theδ¹³C,δ¹⁵N values of defatted muscle andδ¹⁸O values of crude fat and drinking water were determined. The results showed that the stable carbon and nitrogen isotope composition of beef were significantly different, and the same as theδ¹⁸O values of crude fat, but also they were highly correlated with theδ¹⁸O values of drinking water. Therefore, stable isotope technique can distinguish cattle from different regions, and also the main component of cattle feed can be inferred using theδ¹³C values of beef.This article studied the stable carbon, nitrogen, sulfur, hydrogen and oxygen composition of beef different tissues with IRMS, and established the relationship between the dietary C4, C3 plant proportion andδ¹³C of bovine tissues by the animal experiment. At the same time, the stable isotope technique was proved for cattle geographical origin by analyzing beef samples from different regions.These results provided theoretical basis in the food traceability for the stable isotope technology.