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)
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

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

Test Measuring Range Resolution Repeatability
Lactic acid - milk 2 - 250 ppm 0.1 ppm 1.6 ppm
Lactic acid - cream 1.5 - 150 ppm 0.1 ppm 1.3 ppm
Lactic acid ricotta 0.02 - 0.43 g/100g Lactic acid 0.01 g/100g Lactic acid 0.01 g/100g Lactic acid
Lactic acid mozzarella 0.1 - 1.5 g/100g Lactic acid 0.1 g/100g Lactic acid 0 g/100g Lactic acid
Lactic acid yogurt 0.01 - 1.75 g/100g Lactic acid 0.01 g/100g Lactic acid 0.01 g/100g Lactic acid

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

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With the CDR system, you can perform your tests in total autonomy

Neither skilled staff nor a dedicated external laboratory is needed to use our systems. CDR FoodLab® optimizes traditional testing methods, making them faster and easier, while guaranteeing accuracy standards in line with the reference methods.

Analytical kit

CDR FoodLab® Analysis Systems use disposable pre-vialed reagents specifically developed by the research laboratories of CDR. The use of pre-vialed reagents and the analytical procedures allow:

  • a sample preparation that is quick and easy, when needed at all;
  • making analytical procedures extremely fast and easy;
  • removing all needs for complex calibration procedures.

Reagents come in aluminum packages containing 10 test tubes each to perform 10 tests (or packages for 100 tests containing 10 single packages of 10 test tubes each).

Just a few steps and results are yielded right away

Just a few steps will suffice to carry out your analysis in a rapid way in total autonomy. The system is composed of both the analyzer based on photometric technology and a kit of low toxicity, pre-vialed reagents, developed by CDR.

CDR FoodLab® is cost-effective because it does not require the use of expensive equipment and does not entail maintenance, assistance or calibration costs.
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