L-Lactic acid in milk

The chemical analysis of the milk and dairy products for quality control for every stage of the production chain with CDR FoodLabLactic acid is produced by the fermentation of lactose mainly through microbial activity. Its concentration depends on the total bacterial count and can be a useful indicator of the good state of preservation. In addition, the heat treatment at high temperatures, such as UHT milk, reduces the microbial load but does not alter the concentration of lactic acid, which thus becomes an indicator of the “history” of the product. The test can also be run on derivatives in powder (whey, milk, additives) after reconstitution in water.

Analyzers for determining L-Lactic acid in milk and dairy products


  CDR FoodLab for performing a range of tests in milk and a variety of dairy products CDR FOODLAB® CDR FoodLab Junior for performing a range of tests in milk and a variety of dairy products CDR FOODLAB® JUNIOR
Analyses Milk and Dairy Products:

L-Lactic acid
Milk Urea Nitrogen (MUN)
Alkaline phosphatase (ALP)
Hydrogen peroxide
ε-fructosyl-lisine (Furosine)
Free Fatty Acids
Peroxide Value
Configuration with tailored panel of analyses
Simultaneous Sample Analyses 16 3
Multiple Analyses on a Sample si


It is not necessary skilled staff nor a laboratory for the analysis.
Results are correlated with reference method results.
It is free of service and maintenance cost.
With the same analyzers you can also perform analysis of egg, tomato, vegetable purees, cheeses and fats.


Test type: End Point
Time of test: 8 minutes:
It is possible to carry out several test sessions with a maximum of 16 samples.

Test principle

Ac.L-Lactic + der. Fenolico lactic acid reaction chinoneimina + H2O

L-Lactic acid is oxidized to pyruvate by an enzymatic reaction that produces H2O2. H2O2, in the presence of peroxidase and a phenolic derivate, forms a colored complex whose intensity was read at 545nm and is directly proportional to the concentration of L-lactic acid in the sample.

Calibration curve

Comparative tests on samples of whole milk between the reference method and the CDR FoodLab® method, performed in a leading company in production of milk, confirmed a very good alignment between the two systems.

Lactic acid test in milk: CDR FoodLab vs Reference Method


Reagents Test Kits

The reagents are packaged in foil pouches containing 10 tubes useful to perform 10 analyses.

This is the minimum package that allows the use of CDR systems even to those who need to make a few analyses, thus not wasting reagents.

There are also boxes of 100 tests, however, packaged in 10 bags of 10 tubes containing the reagent.

Reagent test kit *300075 suitable for 100 tests

Reagent test kit *300076, suitable for 20 tests

The reagents have a shelf-life of 12 months.

Sample Handling

Use milk as is
Diluted samples: yogurt.
Homogenized samples in a diluted soda solution: cheese, mozzarella, ricotta.

Measuring range

Analisys Measuring range Resolution Repeatability
L-lactic acid milk 2 – 250 ppm 1 ppm 5 ppm
L-lactic acid cream 1,5 – 150 ppm 1 ppm 3 ppm
L-lactic acid ricotta 0,02 – 0,43 g/100g 0,01 g/100g 0,03 g/100g
L-lactic acid mozzarella 0,1 – 1,5 g/100g 0,1 g/100g 0,05 g/100g
L-lactic acid yogurt 0,01 – 1,75 g/100g 0,01 g/100g 0,05 g/100g

For samples with a value of lactic acid >200 ppm (milk) or >150 ppm (cream) use half of the sample volume (50 μL) and multiply the result by 2.

Reagents developed by CDR S.r.l - Quality System Certified ISO 9001 Ed. 2015 - Certificate n. 9115

Click and Discover more about CDR FoodLab®: Tests in few minutes, reference methods compliant. Easy to use also by unskilled staff

L-Lactic acid was last modified: March 7th, 2019 by CDR s.r.l.