The story so far: Laddu prasadams from the temple town of Tirupati have left a bad taste after reports that the ghee from cow milk, the traditional ingredient, may have been adulterated with fat from multiple sources including beef tallow.
What are the allegations?
A technical report from the Centre for Analysis and Learning in Livestock and Food (CALF) of the National Dairy Development Board, which analysed samples of ghee supplied to the Tirumala Tirupati Devasthanams, the manager of the shrine, found that it was adulterated.
There was fat from soya bean, sunflower oil, rapeseed oil, linseed, wheat germ, maize germ, cotton seed, fish oil, coconut and palm kernel fat, palm oil, beef tallow and lard.
Editorial | Politicising the laddu: On the Tirupati laddu and its ‘adulteration’
While allegations that adulterated ghee was being used for preparing the prasadam have been swirling for months, it was the first time that animal fat — from beef and pigs — was mentioned by no less than Andhra Pradesh Chief Minister, Chandrababu Naidu, at a public forum.
What’s the process to find out if milk fat is adulterated?
Milk fat, like all organic fats, consists of triglycerides. They are glycerols connected to fatty acids and the carbon chains that constitute them are a characteristic feature of triglycerides. There are ‘short chain,’ ‘medium chain’ and ‘long chain’ fatty acids defined by the number of carbon atoms in these chains. Milk fat has more than 400 structurally different fatty acids and can combine in various ways to form thousands of triglyceride molecules. Thus, triglyceride patterns in cow ghee differ from the ghee made from goat milk, lard, soya bean or other vegetable oils. Given that cow ghee is expensive, adulterating it with cheaper fat is an age-old practice, and an array of methods have evolved to detect adulteration. For precision, the state-of-the-art method in the dairy industry is the use of gas chromatography. This method can be used to separate the chemical constituents of a sample mixture made up of organic compounds. These machines are expensive and can cost ₹30-40 lakh but are the standard in reputed outlets. Much like an electrocardiogram generates a signal of oscillating waves meant to represent heart beats, the result of a gas chromatography analysis of a sample of ghee is a characteristic wave form that shows the proportion of different types of triglycerides. Pure cow ghee has a characteristic pattern different from vegetable oil or lard (pig fat).
For adulteration analysis, the German scientist Dietz Precht, in 1991, came up with a set of five equations. Each of them generated an ‘s value’ (standard value) and can be used to determine specific adulterations. The value from s1 points to adulteration with soya bean, sunflower oil, rapeseed, fish oil; s2 to coconut and palm kernel fat; s3 to palm oil and beef tallow; s4 to lard and s5 to the total adulterated fat in a given specimen. For a ghee sample to be pure cow ghee, all five of these values must lie in a specified range that’s within a window of 3 or 4 points to 100. However, even if one of these values lies outside the prescribed range, it points to the presence of a ‘foreign fat.’ This process is the standard protocol recommended by the International Standards Organisation (ISO) and followed in reputed Indian laboratories such as CALF.
What did the analysis of fat in the Tirupati laddus find?
Two samples of cow ghee were tested. All of the values (s1-s5) in both samples were outside their prescribed ranges. For example, in one of the samples, the s3 value —linked to palm oil and beef tallow — was 22.43, out of the prescribed range of 95.9 to 104.1. However this alone doesn’t indicate the presence of beef tallow. “Although individual s-values (i.e. s1, s2, s3 & s4 ) are more sensitive for certain foreign fats than the general s-value (s5), the positive result obtained in only one s-value does not allow to draw a conclusion on the type of foreign fat,” says a review of the Precht method in the Indian Journal of Dairy Science in October 2023 by K.D. Aparanthi, of the Anand Agricultural University, and co-authors. “...In actual practice, particular foreign fat generally remains unknown, since most of the foreign fats are identified by the method as a group and not as a particular foreign fat (except lard). [The] same problem also arises when a blend of foreign fats is mixed in milk fat.” Moreover, the number in this case, s3=22.43, doesn’t denote a percentage or the quantity of a substance. Under the prescribed tests, the intrusive ‘foreign’ fat can be calculated when the ‘s’ values exceed 100. This isn’t the case for s3, here.
Are there established methods to differentiate the sources of fat?
There are mathematical ways to interpret the individual ‘s’ values to determine the presence of specific kinds of fat but these haven’t been specified in the CALF report. While these methods were developed for European cows, applying it to Indian bovines could require changing the ‘s’ values. These can be calculated only after a database on the biochemistry of ghee in Indian cows, which may have different genetics, and Indian tallow is known. “There is wide biological variation within a species. However, using spectography methods we can accurately detect the nature and percentage of adulterants provided good baseline data, specific to Indian conditions, is available,” Dr Madhusudhan Rao, scientist at the Centre for Cellular and Molecular Biology, Hyderabad told The Hindu.
Published - September 29, 2024 04:33 am IST
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