Cheese culture media

Characteristics and properties

Culture media are a complex blend of skimmed milk powder, whey proteins, phosphate salts, yeast extracts and other specific growing agents. Culture media are used to improve bulk starter production of cheese as an alternative for skimmed milk to ensure a robust system with a consistent acid production, predictable activity and a high protection against phage infection.

Benefits of Ceska^®-media

Improved cultures yield
The growth of the culture is maximised by optimal nutrition and growth conditions, due to:

• fast adaptation of the culture after inoculation;
• presence of specific minerals and compounds, which stimulate bacterial growth;
• a buffered acidity system, which maximises the bacteria cell counts;
• culture media are free of any inhibitors like e.g. antibiotics.

Protection against bacteriophage infection
Ceska^®-media contains special phosphate salts, which reduce the amount of available Ca₂+ ions. In this way bulk starter becomes less susceptible to bacteriophage infections.
Besides, the presence of phosphate salts buffers the acidity, which results in an increase in cell counts and thus a more robust system in case of high bacteriophage infection.

Figure 1. Final pH of bulkstarter at different initial phage infection loads

Figure 2. Activity of bulkstarter produced with different initial phage infection loads

Fig. 1. illustrates the effect of initial phage infection load of the bulk starter on the final pH after incubation: final pH of the bulk starter is not influenced by a high phage infection load when produced on medium, whereas the final pH stops at a higher level when milk is used as growing medium.
 

When the effect of initial phage infection load on final bulk starter activity is analysed (see fig. 2.), it shows that the activity of bulk starter is more stable at increased initial phage infection load when medium is used instead of milk before a decrease in activity is observed.

Consistent acidification performance
Due to optimal nutrition and growth conditions a robust system is ensured. This results in a consistent acidification performance, a predictable activity and thus an improved final product consistency.

Availability
With Ceska^® -media all milk is available for production, which makes planning of the amount of liquid skimmed milk for bulk starter production not necessary.

Cost effective
An increased culture yield can also be used to reduce the percentage of culture addition up to 20-30%. This results in an energy and cost reduction on the one hand and a capacity increase on the other hand.

Quality of bulk starter
As the bulk starter reaches its optimum at a higher pH with Ceska^®-media than with skimmed milk, the vitality and activity of the bulk starter is higher for longer periods.

Media types

Ceska^®-media are available in a dust free and a dust reduced version. The dust reduced version is specific developed for addition via triblender, whereas the dust free version is agglomerated and specific developed for addition via manhole. The agglomerated version also has a higher solubility.

For every cheese type a specific medium is developed, which is optimal adjusted to the related Ceska^®-star cultures. These media vary in buffering level, ingredient composition and dissolving concentration.