How to Detect Adulterated Milk Fat

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How to Detect Adulterated Milk Fat

Team TFS
Team TFS

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Food products with high market value — like milk, honey, oil and meat — are more susceptible to adulteration. This is a long-term problem affecting the food industry, and difficult to control — especially in some developing countries. Adulteration involves the addition of cheaper ingredients to reduce production costs and increase margins, which can lead to fraud against consumers and products that may be harmful to humans.


Milk fat is an important constituent of dairy products, impacting their nutritional properties and economic value. Due to the growing demand for dairy products, milk fat is a common target for adulteration, with lower price vegetable oils or other cheaper animal fats sometimes used in the manufacturing process of cheese and butter.


At the base of milk fat adulteration is the economic advantage of replacing high-priced fats with low-priced oils without clear labeling on the product.


The dairy industry is a major player in the food industry, and with the recent controversy over milk fat adulteration, it’s important to know more.


The U.S. Food and Drug Administration (FDA) has taken actions to ensure that milk is free of any additives or contaminants, and this includes banned substances like hormones and antibiotics. Further, the FDA requires food companies to display clear nutrition labels on their products (i.e., the content of trans fatty acids). However, the substitution of milk fat appears more often without indications.


Testing the authenticity of milk fat is therefore essential to protect the high standard of dairy products from fraud and safeguard consumers. Both fatty acids and sterols profiles can be assessed to detect milk fat adulteration in dairy products like butter.


The International Organization for Standardization (ISO) and the International Dairy Federation (IDF) have published a reference method for the determination of milk fat authenticity (ISO 17678:2019) based on the triglycerides (TAG) profile.


Gas chromatography with flame ionization detection (GC-FID) is a simple and cost-effective analytical approach to assess triglycerides composition and mass fraction, allowing the identification of added foreign fats. 


A detailed Application Note (AN000136) demonstrates the use of the Thermo Scientific™ TRACE™ 1610 GC in compliance with the ISO 17678:2019 method. The integrity of milk fat can be determined by comparing the triglycerides profile of samples with the one of pure milk fat and applying a set of mathematical equations (S-values) based on the mass fractions of triglycerides ranging from C24 to C54, using even numbers only.


Clarified butter sample (overlaid chromatograms n=9).Clarified butter sample (overlaid chromatograms n=9).


The sample injection is automated with the Thermo Scientific™ AS1610 liquid autosampler on the iConnect PTV injector working in the on-column mode for full recovery of the high boiling TAG, delivering highly repeatable results. Additionally, with the use of Nitrogen as carrier gas, this solution represents a cost-effective approach for testing laboratories.


The results are compared with S-values limits (calculated from TAG percentage) provided in the ISO/IDF method for pure milk fat. Adulterated fat samples will show at least one of the S-values outside the reported limits. In the example reported here for an adulterated butter sample, the S-value related to coconut and palm kernel fat failed, confirming the adulteration.


Example of customized report for an adulterated butter sample.Example of customized report for an adulterated butter sample.


Food testing laboratories involved in the detection and quantification of foreign fats in dairy products with chromatographic methods can be further facilitated by the use of the Thermo Scientific™ Chromeleon™ CDS software for instrument control, data processing and reporting, making the analytical approach very easy.


Automatic integration, quantitation and customizable report options greatly simplify data review, providing an easy interpretation for possible milk fat adulteration.


If you would like to know more about the method by using the TRACE 1610 GC, don’t miss the webinar titled “Authenticity of milk fat based on triglycerides profile by a fast and cost-effective GC-FID method,” available on demand.

Watch the webinar here



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