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pH of Cheese
pH, together with temperature, rank as the most important indicators of food quality and safety. The pH of cheese is measured to ensure that quality standards have been properly met. pH is also monitored at different stages of cheese processing and transformation to guarantee safety and improve production. Along with temperature and water activity, pH is an important determinant in the shelf life of foods. The pH value of cheese varies not only among types of cheese, but also between batches of the same variety. There is also variation throughout the maturation process, decreasing early on and increasing again as the cheese matures. Typically, the pH of cheese ranges from 5.1 to 5.7 with a few exceptions such as Camembert, which has a pH of 7.44. Increasingly pressure is being put on cheese makers to supply end product which has been pH tested.
In consultation with researchers and cheese producers QCL has developed a complete kit for the measurement of all cheese types, in accordance with British Standard BS770.
Our kit includes a meter, ROSS Electrode, cheese blender, stand, calibration solutions and complete SOP documentation.
The ROSS electrode has been selected because it is designed to overcome common problems encountered by traditional electrodes in dairy samples. These electrodes rely on a Silver/Silver Chloride reference system. Protein present in dairy products interacts with Silver, precipitating on the electrode bulb and reference junction. This causes the electrode to become slow to respond, inaccurate and will ultimately shorten its life. ROSS electrodes use a completely different, patented reference system which eliminates the presence of Silver, overcoming the protein precipitation problem.
Many cheese pH methods recommend the use of spear or flat tipped electrodes to allow direct measurement of the sample. These methods struggle with hard cheeses, where sample contact with the sensing bulb of the electrode is incomplete, causing inaccuracies and poor repeatability. The small area tested also gives rise to problems with taking a representative sample. Our method uses a larger sample size to give a more representative result and is compatible with cheese of all consistencies.
The kit is very versatile and can also be used to test the pH of milk, whey and CIP rinse water if required.
Read more on pH Analytical Theory
Ongoing Consumable Requirements
Below is a guide to the solutions and accessories that will be required for the ongoing use of your system. The quantities suggested are best estimates only and may vary in accordance with your usage requirements. The prices quoted are 2008 list prices.
Electrode Filling Solution
This solution is crucial to the electrode operation. It acts as the salt bridge to maintain an electrical circuit between sample and reference. We estimate one pack will need to be purchased per year.
810007 – ROSS pH Electrode Filling Solution - £56.00
Calibration Buffers
For best practice and the most accurate results the pH electrode should be calibrated before each day’s testing. We estimate you will require approximately 1 bottle each of pH 4 and 7 buffer per month.
910104 – 475ml pH 4 Calibration Buffer - £10.00
910107 – 475ml pH 7 Calibration Buffer - £10.00
Storage Solution
In between measurements the electrode should be kept in storage solution. This keeps the electrode in optimum condition, ensuring fast, accurate measurements immediately.
910001 – pH Electrode Storage Solution - £33.00
pH Electrode
The ROSS electrode supplied with the kit is guaranteed for 12 months from the date of purchase. With careful use and a thorough storage, cleaning and maintenance schedule the electrode will last for many years.
8172BNWP – ROSS Sure-Flow pH Electrode - £250.00
For more information on these products please contact the product manager, Jamie Duncan on 01342 820820 or
e-mail enquiries@qclscientific.com.
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