The LR, FAT, SNF & TS Demystified
LR (Lactometer Reading), Fat%, SNF (Solid Not Fat) and TS (Total Solids) are the terminologies that you frequently come across in dairy business. These four are the commonly used indicators of milk quality. SNF and TS values are derived from LR and Fat% through a formula. If you know the LR and Fat% of a milk sample then you can calculate its SNF and TS. In this blog we explain what these values are and how to measure them. Even if you are not into dairy farming; the blog may still be useful - as this can educate you on determining the quality of the milk that you and your family consume. Towards the end of this blog we also share with you our experience of how large corporates tend to cheat farmers, by incorrectly measuring the Fat% and LR values.
Natural milk is composed of several components, these are divided into three categories:
Butterfat % (usually referred to as the Fat%).
Water.
Other solid constituents (commonly referred to as Solid Not Fat - SNF. For example calcium, protein, magnesium etc.).
Pick up your favourite pasteurised milk carton e.g. Prema or any other brand that you use. Turn the carton around and you would see the Fat% and SNF (solid Not Fat) values printed on the carton. The fat, water and SNF values of milk vary according to the type of animal, its breed and its feed intake. For example, buffalo milk contains ~6.5 % fat whereas cow milk contains between 3.1 - 4.5% of fat. The fat% also vary from one breed of cow to another. For example, Holstein Friesian breed's fat% is usually between 3.6 - 3.7% and jersey's fat% is usually between 4.4 - 4.8%. Desi cow breeds (e.g. Sahiwal) have fat% of ~4.5%. As stated above, the fat% not only depends on the animal breed but also the quality of food intake. The more nutritious the animal's food the higher the fat% in the milk.
Natural milk contains anywhere between 85-90% of water and 10-15% of solids. Obviously, the real nutrition of the milk comes from the solids and not from its water contents; therefore the milk collection companies price the milk from the farmer based on the solids in the milk. To determine the solids the companies measure two critical components in the milk: Fat% and LR.
They use Gerber method to measure the milk fat% and Lactometer to measure the LR value. While Gerber method requires special equipment (Gerber centrifuge, Butyrometer, pipettes etc. ) & chemicals (sulphuric acid, alcohol) and can only be carried out after some training; however LR can be easily calculated. In my research I have found out that reasonable quality Gerber equipment for measuring Fat% can cost between PKR 11,000 - 13,000; whereas the equipment for measuring LR can cost between PKR 300 - 450.
Let us now show you how you can measure the LR value of a milk sample.
You would need the following equipment to measure the LR of a milk sample:
Container for the milk sample.
Thermometer to measure the temperature of the milk.
Lactometer
In the video below, we show you the process of measuring the LR of the milk sample:
The theory behind LR value measurement is very simple. LR value is based on the concept of "density". Scientifically speaking, density is defined as mass per unit volume. Simply put, it determines how thick (or heavy) a liquid is. The density of the water is considered to be: 1 g/cm³, the density of milk is around: 1.035 g/cm³, the density of honey is 1.33 g/cm³. Therefore honey will be thicker than milk and milk will be thicker than water . Lactometers are usually calibrated such that when they are immersed in pure water at a temperature of 20 C then the lactometer will immerse completely in the water and gently sit at the bottom of the container and the LR value will be zero. When it is immersed in pure milk which is at 20 C temperature then the Lactometer will show a reading between 26-32. A value below 26 indicates that water has been mixed into the milk and a value higher than 32 indicates that solids have been added to the milk. Milk with LR lower than 26 or higher than 32 should both be rejected as "impure".
Since Lactometers are usually calibrated at 20 C temperature; therefore if the milk temperature is different than 20 C then a correction should be applied. For every one degree temperature above 20 C add 0.2 to the LR value and for every one degree temperature below 20 C subtract 0.2 from the LR value. For example if the milk temperature is 30 C and the observed LR value is 26; then the correct value of LR should be: 26 + (10 * 0.2) = 28.
Now that we know about the Fat% and LR values of the milk let us calculate the SNF. The formulae for SNF that milking companies use in Pakistan (Engro foods and Nestle) is given below:
SNF = (0.25 * LR) + (0.22 * Fat%) + 0.72.
the formula for Total Solids (TS) is:
TS = Fat% + SNF.
Let us assume that for a given milk sample the Fat% as measured through the Gerber Test is 3.7% and the LR is 27. The SNF would be:
SNF = (0.25 * 27) + (0.22 * 3.7) + 0.72 = 8.284
TS = 3.7 + 8.284 = 11.984
Now that we know all about Fat%, LR, SNF and TS - let us see how these values are used by Nestle and Engro foods to determine the payment for the dairy farmers.
The milk collection companies base their payment formula on a standard TS value of 13. For example if the milk companies pay PKR 40/liter, then when you deliver one liter of milk that has a TS value of 13, they will pay you PKR 40. But if your TS value is 11.984 (as is the case in the example above) then your one liter will be considered equivalent to 0.922 liters and you will be paid PKR 36.88.
Now that you know all there is to know about LR, Fat%, SNF, TS and the milk payment systems that Nestle and Engro adopts - here is the million dollars news flash:
It has been our experience that Nestle milk collection unit in our area (Chak 431 TDA, District Layyah); has been cheating us and all other dairy farmers for a long time. After having learnt the details of TS calculation, I calculated the Fat and LR values of our dairy farm. I was surprised to note that my calculated values did not match with what Nestle has been using to determine our payment. I sent our milk for analysis to Engro foods and was relieved to notice that their values did match mine. I then visited Nestle collection center and asked the operator to measure the Fat% and LR in front of me. The Fat% was correctly measured. As for LR, the lactometer was clearly showing a value of 28.5. The temperature was 30 C. So the corrected LR value should have been 30.5. But he noted down the value to be 27. When I explained him that I know how to calculate LR and that he has incorrectly specified the value to be 27; even by Nestle's own standard it should be 30.5. He started mumbling some gibberish. I showed him Nestle's SOP which was publicly displayed in the collection center. He still did not budge. He then told me that he will measure the LR again by cooling the milk to 20 C. I agreed to it. Even after cooling the sample down to 20 C (which he did by dipping the milk container in the chiller); the reading was still 30.5. He then gave me some convoluted reason for why he insists to report the value of 27.
We have decided to report this matter to Nestle head office in Lahore. We don't believe that this fraud is propagated by Nestle head office. We believe that Nestle's area manager or the collection center supervisor are committing this fraud without the knowledge of Nestle head office. Hopefully we will get through to competent authorities in Nestle head office and action will be taken against these frauds.
Needless to say, we have decided to move from Nestle to Engro foods and soon will be giving the milk to Engro. Please spread the word in your area and do your best to ensure that dairy farmers are not cheated by these corporates.
