BS ISO 4134:2021

What is ISO 4134 about?  

ISO 4134 specifies the spectrophotometer method and the light absorption microplate reader method for the determination of the free L- (+)-glutamic acid content of meat and meat products. 

ISO 4134 is applicable to meat and meat products, including livestock and poultry products. 

Who is ISO 4134 for? 

ISO 4134 on glutamic acid content is relevant to:  

• Meat food manufacturers and suppliers 
• Food technologists 
• Food laboratories 
• Food safety and regulatory bodies 
• Nutritional testing agencies 

Why should you use ISO 4134?  

Glutamic acid is an α-amino acid that is used by all living beings in the biosynthesis of proteins. 

All meats, poultry, fish, eggs, dairy products contain extreme amounts of glutamic acid.  

ISO 4134 helps users, by specifying the spectrophotometer method and the light absorption microplate reader method, to determine free L- (+)-glutamic acid content of meat and meat products. 

Methods specified in ISO 4134 are applied to measure moisture, fat, protein, and carbohydrate content in a wide variety of foods.  

ISO 4134 describes methods for determining glutamic acid and provides information regarding packaging and preserving meat in a way that its quality is maintained and its shelf life is prolonged, thus ensuring safe-to-consume products are made available. 

What is changed since the last update?  

BS ISO 4134:2021 supersedes ISO 4134:1999. BS ISO 4134:2021 includes some technical changes with respect to ISO 4134:1999. These include: 

• A new test method, the light absorption microplate reader method, has been added 
• In Clause 4, the description of “extraction of L-(+)-glutamic acid of test portion” has been modified and the detection wavelength has been changed from “492 nm” to “490 nm” 
• In 7.1, the identification of enzyme activity units for diaphorase and glutamate dehydrogenase has been supplemented; the concentration of KOH, NAD has been modified; the NAD and diaphorase have been mixed into a solution; and the buffer, NAD and enzymes have been labelled with R1, R2, and R3 
• In 7.3, the procedure of the test method of spectrophotometer has been modified by halving the sample mass and solution volume 
• In 7.3.4, the method of judging the absorbance of the reaction end point has been modified and, as a result, the previous Annex B “Example of plotting and extrapolation of absorbance values” has been deleted