Micro-organisms in Dairy Products

Incubator Application

Hettich Incubator Application

The use of HettCube incubators and cooled incubators to quantify micro-organisms in milk and dairy products

Micro-organisms can metabolize the constituents of milk and thereby modify its taste, as well as impacting the processing and shelf life of milk and dairy products. Milk and dairy products are therefore tested to ensure that limit values are not exceeded. The presence of micro-organisms is of particular importance in foods for infants and small children. Manufacturers must, therefore, determine the number of micro-organisms present in their products every month.


DIN EN ISO 4833 describes a method for the enumeration of micro-organisms. decimal dilutions of the sample are pipetted into sterile Petri dishes and mixed with a colony-counting medium that is liquefied and cooled to 44 °c to 47 °c. As soon as the mixture has solidified it is incubated. no more than six Petri dishes can be stacked on top of one another during incubation. The dishes are evaluated under diffuse light and a magnifying glass used for counting if necessary to avoid confusion between colonies and other particles.

Importance of quantifying micro-organisms in milk and dairy products

Under dairy product regulations the number of micro-organisms present in milk and dairy products must be determined at regular intervals. The controls are required at intervals ranging from every 12 weeks to every 2 weeks, depending on the susceptibility of the product to spoilage.

Incubation conditions according to DIN EN ISO 4833:

Temperature: 30 ± 1 °C
Duration: 72 ± 3 h

Hettich products are designed to help you achieve optimal results for your application and are built to perform to the specifications outlined in the operators manual. For application-specific information and settings, please refer to your organization’s standard operating procedure. As always, our Hettich representatives are here to help determine which Hettich products and accessories best fit your laboratory requirements.

HettCube Incubators

Hettich Hettcube incubators and cooled incubators are built to maximize their compact footprint with efficient design features that improve temperature uniformity, operational performance, and user interaction.

HettCube series of incubators


Micro-organisms in Dairy Application Note

This application note provides information on specific application methods and the use of Hettich products. (more…) read more...

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Hettich HettCube incubators product sheet

HettCube Product Sheet

This product sheets provides a comprehensive overview of the unique product features specific to the model. (more…) read more...

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