Why is it important to measure pH in milk?

Measuring the pH of many food products is integral to successfully processing them and achieving the best, most consistent outcome to comply with nutrition and product requirements.

Milk, in particular, needs to maintain a specific pH level to remain fresh. A pH that's too far one way or the other can indicate problems with the milk or suggest it is about to turn. This information is integral for processing and providing safe dairy products for customers and food production companies.

While pH isn’t the only thing affecting the production and safety of milk, understanding why pH measurements are important is key to maintaining good monitoring habits and properly managing processing.

What is the pH of milk?

Firstly, before we cover why milk pH is important, what is the typical pH of milk? The pH of your average fresh milk is between 6.5 and 6.9. This number is slightly below neutral, at pH 7, due to the lactic acid found in milk. There is a slight variation between species, such as goat or sheep milk, compared to cow's milk, but on average, most types of milk remain arouud the acidic side of neutral.

The average ranges for the most common milk types include:

• Cow milk: 6.5 to 6.9 pH
• Goat milk: 6.6 to 6.8 pH
• Sheep milk: 6.6 to 6.7 pH

What’s the most important thing to know about milk pH level? This parameter is, first and foremost, a quick and easy way to identify compositional changes in the milk during processing and production.

pH provides the insight that milk processing plants and other businesses need to get their products ready for sale, maintaining the necessary standards of safety while also ensuring milk is fresh to begin processing.

Why is it important to measure the pH of milk?

Measuring the pH of milk provides immediate insight into several problems that can affect milk production.

Firstly, measuring pH immediately following the collection of milk can identify if there is any compositional difference outside of the normal range, allowing for quick identification of conditions such as mastitis in cows that can alter the acidity of their milk. 

Secondly, measuring at the point of production provides information about whether milk is fresh or has started to coagulate or curdle. Milk needs to be fresh to be safe for use and to maintain a longer shelf life.

Milk processing plants can quickly adjust their processes and make informed decisions about how to manage their milk by measuring pH to check for freshness. pH testers and meters provide accurate information to tailor treatment, reducing wastage and ensuring consistency in the end product.

When should you test the pH of milk?

Testing the pH level of milk is useful in every stage of the process. Farmers may use pH testing equipment to identify mastitis in cows, allowing for prompt treatment. A cow with an infection releases histamines and other infection-fighting compounds, which are then transferred into the milk due to increased permeability in the endothelial and epithelial cell layers. This transfer increases milk's pH due to the alkaline nature of blood plasma that passes through the cell layers.

Once the milk is transported to a processing plant, pH testing is vital for setting the correct time for pasteurisation, a technique required for ultra-high temperature (UHT) processing to gain stability. Even relatively small pH variations can make a big difference in how long pasteurisation takes, making it vital to accurately read the pH of the milk before beginning the UHT process.

Whether the treated milk is being used as a component in other dairy products such as cheese or butter or being packaged for sale in shops, it’s equally important for pH testing to be conducted. As with any product for human consumption, milk must be monitored and maintained to prevent sickness and risk.

How do you measure the pH in milk?

A standard pH meter seems like the correct choice when measuring the pH in milk, but the nature of this food product means you'll want something more specialised.

A specialised pH meter designed for milk is the ideal option to measure this food product. The solids within milk can cause clogs in general pH testers, leading to inaccurate readings. Hanna stocks several purpose-designed milk pH meters for accurate and reliable testing:

HI-98162 Professional pH Meter for Milk

The HI-98162 portable meter is a pH meter for milk designed specifically for use in the dairy industry. The HI-98162 comes equipped with a specifically designed FC1013 pH electrode, created from food-grade plastic with resistance to radiation, ultraviolet, abrasion and fungal growth. This meter is IP67-rated, protecting it from spills and drops, and has automatic and manual temperature compensation for exceptionally accurate measurement. Buy it here.

Halo2 pH Bluetooth Electrode for Milk

The compact Halo2 is a simple pH tester for milk that connects directly to the Hanna Lab app, allowing all tests to be recorded and stored directly on a smartphone or tablet. This handheld milk meter features a conical tip ideal for semisolids and liquids for easy immersion and has a single-button operation for easy milk testing. Low-temperature glass construction ensures fast, accurate stabilisation in lower temperatures. Buy it here.

HI-99162 Portable pH Meter for Milk

The HI-9961 portable milk pH meter is an accurate and reliable option for measuring the pH and temperature of milk at the same time. This meter includes an FC1013 pH electrode with a PVDF body and double junction reference with refillable bridge electrolyte and ceramic junction, with a watertight probe connection for safe measurement at all steps in milk processing. Buy it here.

Buy pH testers for dairy from Hanna Instruments

Reliable pH measuring technology makes your job easier and saves you time. At Hanna, we stock testing equipment for various food industries, from milk and cheese to beer and cider, to deliver the best solution for your needs.

Browse our range of food testers for dairy online now, or get in contact with our team directly to chat about your food-safe testing requirements.

Call 01525 850 855 or email us at sales@hannainstruments.co.uk to discuss your requirements.