Say cheese!

• Cheese factory uses more sustainable filtration process
• Results in better product quality, less costs and reduced chemical use

Immersion of cheese in brine is an important step in the production process to ensure taste and optimal storage life. The Austrian company Pantreon was looking for a more efficient filtration process for its products.

After several tests run on different locations over eight years, the company chose to apply polytetrafluoroethylene (PTFE) membranes with a pore size of 0.1 micron for the filtration of brine in cheese pasteurisation. For the best long-term performance of the brine filtration units (ZELIX), a continuous run is preferable to stop-start batch operations. To perform continuously like that, the ZELIX is run in bypass with a concentration tank, which is used as a cleaning-in-place (CIP) tank. This type of ZELIX can hold about 250 litres (66 gallons), while the concentration tank takes 1 500 litres (456 gallons). So, the filtration process can be prolonged for around six cycles which keeps the unit running continuously for much longer periods.

The ZELIX membrane filtration runs around the clock at its Gmundner Molkerei plant for up to ten days continuously. During that time, about 50 m3 of brine can be filtered and recycled to the brine tank as clear permeate without any dry substance, and it is germ free. The germs are collected in the concentration tank and further concentrated at the end of the filtration process from 1 750 litres to 550 litres; the concentration rate of filtered brine to separated residue volume is up to 90:1.

Key results

The new filtration system offers 100 % separation of all relevant brine microbiological parameters. The advantages of continuous membrane filtration of brine are:

• General increase in the lifetime
• Microbiological control without chemicals
• Controlled cheese quality
• Increased efficiency of the salt content
• Higher degree of salt absorption in the cheese
• Higher production rate
• Reduced volume (and cost) of brine residues for disposal