Milk is a highly nutritious food composed of water, fat, and solid components. The portion of milk that remains after removing fat and water is called Solid-Non-Fat (SNF). It includes essential nutrients such as proteins, lactose, minerals, and vitamins that contribute to the nutritional value and quality of milk.
SNF testing is an important aspect of dairy analysis used to assess the purity and quality of milk. It helps in detecting adulteration, especially dilution with water, and ensures that milk meets regulatory standards set by organizations.
Instruments & Glasswares used during the test of Solid Non Fat (SNF) in Milk Sample
- Analytical Balance(4 digit) :To accurately measure the mass of glasswares and samples before and after drying.
- Water Bath:A container of hot water produces steam heat to evaporate water from the sample in the dish more slowly and uniformly before final drying. This reduces splattering and loss of solids.
- Hot Air Oven(105°C) :To dry the sample to constant mass by evaporating water.
- Desiccator :To cool dry samples without moisture absorption from the air.
- Silica Crucible(50ml) :Holds the liquid food sample while water is evaporated and then while drying the residue.
- Heating Mantle: Maintains constant temperature to ensure uniform extraction and safe evaporation of solvents without degrading fat.
- Condenser- It is attached on top of the extractor that condenses solvent vapour back into liquid through the sample.
- Splash Head Condenser – It operates between the flask and the condenser while recovering the ether.
- Recovery Funnel – It attached with the condenser while recovering the ether.
- Beaker : For sample measurement.
- Measuring cylinders(1ml,10ml & 25 ml) : Used for measurement of solvents into samples.
- Flat Bottom Flask : Holds fat-solvent mixture for evaporation to leave pure fat residue for weighing.
- Water Supply : Provide constant water supply during extraction to maintain the temperature of condenser.If water flow discontinued then condenser become heated & break the condenser.
Chemicals used to Test Solid Non Fat (SNF) in Milk Sample
- Ammonia solution : Breaks protein–fat bonds, releasing fat from milk proteins in alkaline medium
- Ethanol (95%) : Prevents formation of emulsions, aiding complete fat extraction.To prepare 95% ethanol add 95 ml ethanol in 5 ml distilled water.Down graded ethanol may take huge time to remove emulsion which remains in fat,affects in result.
- Diethyl ether : Dissolves almost all milk fats due to non-polar nature.
- Petroleum ether: It ensures complete extraction and reduces residue volatility.
- Distilled water & Acetone: Used for dilution and cleaning, preventing contamination and maintaining accuracy.
Procedure of Solid Non Fat (SNF) test in Milk Sample
| Total Solid | Procedure described previously |
| Fat Determination | Procedure described previously |
| Solid Non Fat | SNF(%)= (Total Solid – Fat) |
Why Solid Non Fat (SNF) is important to test in Milk?
- Indicates overall quality and nutritional value of liquid milk.
- Helps detect adulteration or dilution with water.
- Ensures compliance with standards (e.g., Food Safety and Standards Authority of India) Important for process control in food industries.
- Ensures consistency in taste, texture, and concentration .
- Affects shelf life and product stability
- Helps in standardization and formulation of food products
Handling Precautions taken during Solid Non Fat (SNF) content test in Milk
- Using unclean or wet glassware, leading to contamination.Proper cleaning Process described previously.
- Improper mixing of the sample before testing.
- Taking readings at wrong temperature without correction.
- Delay in testing causing sample deterioration.
- Incorrect measurement of fat% affects SNF calculation.
- Not calibrating instruments properly.
- Spillage or loss of sample during handling.
Conclusion of Solid Non Fat (SNF)testing in Milk Sample
The determination of Solid-Non-Fat (SNF) content in a milk sample is an essential test to evaluate its quality, purity, and nutritional value.By following these method,you can easily test the fat content at any laboratory or manufacturing industry with availability of the equipments & chemicals.If you can’t understand the procedure you can check our real time photo attached with this writing or also you can reach to Pro Research & Testing Laboratory for the testing purposes.
FAQ of Test Solid Non Fat (SNF)content in Milk Sample
What is SNF?
SNF (Solid-Non-Fat) is the portion of milk excluding fat and water; it includes proteins, lactose, and minerals.
Can SNF be measured directly?
No, it is usually calculated indirectly using fat % and total solid.
Can SNF testing detect all types of adulteration?
No, it mainly detects water dilution; other tests are needed for chemicals or synthetic adulterants.
What happens if SNF is higher than normal?
It may indicate concentrated milk or addition of solids like skim milk powder.
Why is proper mixing of milk necessary before testing?
To ensure uniform distribution of fat and solids for accurate readings.
What is the role of SNF in making dairy products?
It influences yield, texture, and quality of products like curd, cheese, and milk powder
How We Verified This Testing/Research Procedure :
This testing is done under qualified analysts in our lab.Continually monitored by expertise.Repeatedly testing is always done to get accurate result.
Written by
Riya Ghosh (M.Sc. Food Technology, MAKAUT)
Designation – Chemist
Reviewed by
Anwesha Das (M.Sc Microbiology,BU)
Designation – Microbiologist
Verified By
Dr. Jyotirmoy Kumar Dey (Phd,Chemistry)
Designation – Senior/Chief Chemist
Experience – 25 Years +