pH Measurement of Yogurt

Yogurt is sold in grocery stores, restaurants, coffee shops, and in countless more places. It is a popular snack—often chosen for its flavor and healthy alternative. Because of its widespread popularity, manufacturers have a responsibility to make sure that the process of making yogurt follows safety standards. A sure and reliable way to keep track of the yogurt process is by measuring pH with a dependable electrode.

 

Yogurt is made through the fermentation of milk. From the time the production begins to when yogurt is successfully produced, pH is used to keep track of the acidity levels. Without pH, it will be harder to pinpoint the bacteria activity, making it harder to know when to stop one process and begin another.  

 

The process of making yogurt begins with milk concentrate mixed with other dairy products and sweeteners. Afterwards, the following steps include: homogenization, pasteurization, fermentation, heating, cooling, and packaging.

 

First, milk temperature is raised to 185 - 194°F and then cooled down to 108 - 113°F. The heating of milk will kill any unwanted microorganisms and improve the viscosity of the milk protein. Then, a starter culture is added to milk. This starter culture is a specific type of bacteria (Lactobacillus bulgaricus and Streptococus thermophiles) that will initiate the fermentation of the milk. During fermentation which lasts about four hours, the starter culture turns lactose in the milk into lactic acid which in turn lowers the pH level to around 4.25 to 4.6. When the pH drops, the yogurt is able to coagulate. pH in fermentation will help manufacturers make sure their yogurt is being produced properly. Fermentation is when yogurt achieves its characteristic flavor. If the pH level is not properly monitored, discoloration and unsatisfactory yogurt taste will occur.

 

 

Once the soft thick gel has formed to resemble the texture of yogurt, the yogurt is cooled down to 45°F to stop the fermentation. Keep in mind that the fermentation process can take up to a few hours before the desired texture is reached. By now, the yogurt should have been properly made with the help of pH. Extra flavoring or fruits may be added before packaging and distribution.

 

Because of the direct contact with the food product, the electrodes used must meet sanitary standards. Reliability is also a must since quality and flavor of yogurt is dependent on pH. Sensors must be able to withstand high heat environments. During the yogurt production, heat is increased and decreased multiple times to ensure that unwanted bacteria are eliminated. Sensors must also be able to handle cool temperatures and quickly adjust to temperature variations.

 

These requirements posed in the yogurt making process are easily met with a Sensorex product.

 

The Sensorex S175CD Spear Tip electrode works well with yogurt applications. The sensor’s epoxy body is robust and virtually unbreakable. With its spear shaped tip, it has the ability to penetrate through semi-solid objects such as meat, sausage, cheese, yogurt, and soil. The electrode is also built with a double junction reference which will ensure protection from samples that might contaminate the reference junction. The spear tip electrode comes with a BNC connector (other connectors available upon request) and can be used with virtually any handheld or online meter on the market.