The Gerber method is a primary and historic chemical test to determine the fat content of substances, most commonly milk and cream. The Gerber method is the primary testing method in

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and much of the world. The fairly similar

Babcock test The Babcock test is an inexpensive and practical procedure to determine the fat content of milk. It is named after its developer, Stephen M. Babcock (1843–1931), professor at the University of Wisconsin.Stephen M, Babcock (1890): "A New Method ...

is used primarily in the

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, although the Gerber method also enjoys significant use in the U.S. as well. The Gerber method was developed and patented by Dr.

Niklaus Gerber Niklaus Gerber (8 June 1850 – 9 February 1914) was a Swiss dairy chemist and industrialist. He was born in 1850 in Thun, Switzerland. He attended the University of Bern and University of Zurich The University of Zürich (UZH, german: Un ...

Switzerland ). Swiss law does not designate a ''capital'' as such, but the federal parliament and government are installed in Bern, while other federal institutions, such as the federal courts, are in other cities (Bellinzona, Lausanne, Luzern, Neuchâtel ...

in 1891. Milk fat is separated from proteins by adding sulfuric acid. The separation is facilitated by using

amyl alcohol An amyl alcohol is any of eight alcohols with the formula C5H12O. A mixture of pentyl, amyl alcohols (also called amyl alcohol) can be obtained from fusel alcohol. Amyl alcohol is used as a solvent and in esterification, by which is produced amyl a ...

and centrifugation. The fat content is read directly via a special calibrated butyrometer. Gerber developed specialized butyrometers (tubes),

pipettes A pipette (sometimes spelled as pipett) is a laboratory tool commonly used in chemistry, biology and medicine to transport a measured volume of liquid, often as a media dispenser. Pipettes come in several designs for various purposes with diffe ...

, and

centrifuges A centrifuge is a device that uses centrifugal force to separate various components of a fluid. This is achieved by spinning the fluid at high speed within a container, thereby separating fluids of different densities (e.g. cream from milk) or l ...

. Water baths built specifically for the Gerber tubes are often used. The test is still in widespread use today and is the basis for numerous national and international standards such as ISO 2446, International Dairy Federation (FIL) Regulation 105, BS 696 (United Kingdom), and IS 1223 (India). Larger facilities may prefer to use faster analysis techniques such as

infrared spectroscopy Infrared spectroscopy (IR spectroscopy or vibrational spectroscopy) is the measurement of the interaction of infrared radiation with matter by absorption, emission, or reflection. It is used to study and identify chemical substances or function ...

as these greatly reduce the potential for user error and reduce the time and COSHH requirements. The test continues to be improved and standardized.

Problems likely to be encountered during Gerber butterfat content determination

The two major defects associated with the Gerber method include: # Charring – is observed as tiny black specs at the fat/non-fat interface in the butyrometer. This problem is due to charring of the milk proteins by the concentrated Gerber acid. It could also arise as a result of pouring the milk sample directly onto the acid in the butyrometer. To avoid charring, first, ensure the acid concentration is right. Secondly, while adding the milk sample, let it flow on the side of the butyrometer to avoid violent reaction when it drops on the surface of the acid. # Light colored fat column (with or without brown specs at the interface) – may affect your ability to read the fat content correctly. This problem is due to weak acid, which fails to dissolve all the milk non-fat content. To avoid this problem, use sufficient volumes of the Gerber acid at the correct concentration.

References

External links

Gerber method procedures
*A good explanation of th

for the Gerber test] *Th
ultimate guide to the Gerber method
of butterfat content determination. *check the
efficiency of Sterilization
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