Operations

Finding the Sweet Spot in Cheese

Andechs Dairy employs a new efficient approach to quality control

The Andechs Dairy Company, situated in the quiet countryside of Andechs, in Upper Bavaria, Germany, manufactures milk products from a daily intake of 230,000 liters of milk from ecologically controlled land cultivation. This family concern, with a staff of nearly 200, works under the company motto "keep natural products natural," producing natural foods ranging from yogurt to tasty cheeses.

To better automate the salt content determination of its cheese, and in an effort to improve quality control while uncovering additional cost savings, Andechs searched for a smarter solution.

Up until 2002, Andechs Dairy laboratory had relied on the Erbacher method to determine the salt content (chloride) in cheese. In this traditional method, the cheese sample is digested with potassium permanganate to oxidize organic substances. A solution of glucose is then added to reduce the excess potassium permanganate until a clear solution is obtained. However, under this process, the chloride content in this solution can only be determined indirectly, because the pH value is unsuitable for a direct titration. Further, just four samples could be processed at a time, due to limited availability of digestion apparatus. Finally, this procedure was very time-consuming, as digestion required constant attention and monitoring.

Hoping to double the sample capacity throughout for salt content determination, the quality control laboratory considered two options: increasing the number of laboratory personnel or automating the analytical procedure. It was soon determined that automation through improved technology was a smart and efficient solution.

Andech's laboratory manager, A. Höck, approached the challenge by first discussing the possibility of developing an improved method of cheese analysis, using a titrator and a sample changer. This new, automated method was developed and thoroughly tested in the Mettler Toledo application's laboratory on site at Andechs. In this method, Andech's cheese is weighed into the titration beaker and placed on the Rondo 60-sample changer turntable. The method is initiated at the DL58 titrator, after entering the sample data (weight). First, a 70% propanol solution is added, and the cheese is automatically homogenized in the homogenizer. The chloride is titrated directly in this solution with silver nitrate. The titrator calculates and automatically records the salt content of the cheese in percentages. In this test, exact results were obtained as with the previous method - but reproducibility was significantly improved through automation.

Closer investigation demonstrated that automation with the titrator and sample changer resulted in a number of important advantages:

TIME-SAVINGS: The method is much less labor-intensive. Therefore, laboratory personnel can turn their attention to other important tasks.

ECONOMICAL: The consumption of reagents is greatly reduced; cost savings are experienced by virtue of fewer chemicals used for each analysis.

ECOLOGICAL: Potassium permanganate is no longer used and silver nitrate consumption is significantly reduced through direct titration.

REPRODUCIBILITY: Both reproducibility and comparability of the results are improved.

PAYBACK: The payback period for the investment was just 10-11 months.

AVAILABILITY: The availability of the system is further guaranteed, in fact, by a comprehensive repair and performance service contract.

Andechs has put a DL58 titrator and a Rondo 60-sample changer system, equipped with a homogenizer and printer, into routine operation. "The new system fulfills all our requirements exactly," shares Höck "We are very pleased with the advice and support we get from Mettler Toledo, as well." The new technology provided a return on investment of just 11 months. The investment saves $20 on chemicals and 45 minutes on analyzing for every 10 analysis performed.

Mettler Toledo is a leading global supplier of precision instruments, weighing equipment, and related analytical technology for use in laboratory, industrial and food retailing applications. For more information visit www.mt.com/us.