Indicator of Food Quality and Safety
The pH, together with temperature, ranks as the most important indicator of food quality and safety. The pH is monitored at different stages of food processing and transformation to guarantee safety, improve production and enhance quality. Along with temperature and water activity, pH also determines the shelf-life of foodstuff.
The pH of milk is a parameter for impurities and signs of infection. It is measured upon collection as well as at point of delivery. Higher pH values for fresh milk indicate udder infection (mastitis) and lower values are an indication for bacterial action. In processes such as sterilization, pH is checked since a lower value helps to speed up the process. Milk used for cheese manufacturing must be of excellent quality and its pH value determines whether the cheese will be soft or hard.
The pH is checked during cheese preparation, souring of milk and cream maturation. For example during the production process of cheese, the standard is to monitor the pH value before the cheese proceeds into the brine bath. It is an important measure for the quality of the end-product.
The ISFET pH sensor probes are uniquely suited to measure pH in all sorts of milk (among others whole, low-fat, yoghurt drinks) and milk products like cream and cheese. Problems associated with conventional glass electrodes, like breakage into small glass splinters, are eliminated. Using the non-glass pH probes saves time and simultaneously increases the products’ quality control efficiency.
The positions of the ISFET and reference electrode have been designed to be clog and pollution resistant. In the event debris has accumulated on the sensor it can be easily cleaned by stirring periodically in warm tap water with a mild detergent. Afterwards, the probe tip can be scrubbed with a soft brush in this solution and rinsed with deionized water. Cleaning regularly is of benefit for the probe’s performance and prolonged life.
Worldwide hundreds of types of cheese are produced. Not only their styles, textures and flavors differ, but also the hardness varies. Therefor, we have several probes available each with its own advantages. These are the most used probes for cheese pH measurements:
- The MicroFET is the probe with a diameter of just 3 mm diameter. It can be used for rather soft cheeses. After measuring the pH in the cheese, the hole will disappear and will avoid a hole in the end-product.
- The ConeFET has a diameter of 10 mm and is used for the conventional cheeses that are still a bit soft in the phase before the cheese proceeds into the brine bath. Here, the hole normally disappears as well, so the cheese can still be used for sales.
- The LanceFET probe is steel tipped for penetration into hard cheeses.