It is no surprise that fresh milk (pasteurised) makes up a big part of the typical British shopping basket; with about 4.9 billion litres sold annually. What is perhaps less well known is that around 7% of all that milk goes to waste! This costs us the consumer around £150 million per year in the UK alone.
The reasons for all this waste are complex, including milk being past its ‘use by’ date, spoilage and simple spillages. However, over a third of the milk that was wasted was simply due to too much being served or personal preference such as being fussy, and in fact, less than 10% of the wasted milk was due to accidents and spills.
This leaves most of the wasted milk being either off or past its ‘use by’ date. In 2012, it is suggested that around 40% of the milk that was wasted was due to it being sour or thought to be off, but the date of expiry was not checked. This could offer simple suggestions on how food waste could be reduced in the case of milk. A simple way perhaps would be to only buy the milk we need, this may be possible where consumer’s homes are served by traditional milk round delivery. However, these are not universal and can be more expensive, and therefore not an affordable option for some families. Therefore, for most families, it means judging and juggling how much milk we need when we are at the supermarket.
Other ways to help minimise milk waste involve considering how it is packaged, including looking at roles for novel light-protected packaging which could help to keep milk fresh and protect the important nutrients it contains from damage caused by light. Such approaches should be used in conjunction with using your fridge properly. This means checking the temperature of the fridge, this is not always helped by there being no standards with respect to temperature dials or controls in fridges. So, it is best to check if your fridge at home is colder if you move the dial up or down.
To be sure that your fridge is at the correct temperature, which the Food Standards Agency (FSA) in the U.K. suggest is below 5oC, a fridge thermometer is a good idea. Maintaining the correct fridge temperature will not just help keep your milk fresher for longer, but along with safely storing cooked and raw foods separately will reduce your risk of becoming ill from food-borne illnesses. In fact, WRAP, a UK-based sustainability advisory, even advocates turning temp of fridge down a degree.
Why does milk spoil?
In another article we take a close look at why milk needs to be treated in processes such as pasteurisation and ultra-heat treatment (UHT). But, in simple terms milk spoils for two reasons, one being it is not sterile (unless it is unopened sterilised milk, of course) and the other is that milk is not only nutritionally desirable to many humans, it is a great environment for many bacteria to grow in too.
As these bacteria can be found in the air and environment around us, every time the bottle is open some bacteria can get into the milk. So, to help minimise this it is best to keep the lid on the milk as much as possible and return it to the fridge as soon as you can, as the low temperature of the fridge helps to slow down the growth of the bacteria, helping to keep it fresher for longer.
How long do the nutrients last in the fridge?
Modern ways of pasteurising milk also help to reduce the oxygen level in milk which appears to help reduce the loss of vitamins. This can minimise the loss of folic acid (important for healthy blood) and vitamin C (needed for the immune system and maintaining healthy joints), as both of these vitamins can be damaged being oxygen. Keeping milk in a dark (as in the fridge with the door closed) or in light protective containers can also help retain the riboflavin (vitamin B2), required for energy release from food, in the milk too.
Not just about the environmental impact
With the increased awareness of the environmental aspects of food waste, especially given the increased energy and greenhouse gas emissions linked to dairy products, including milk compared to many plant-based foods it is important to look at ways to minimise waste. But it also seems sensible to try and reduce waste by storing foods such as milk better, as this will not only help retain their fresh flavour but will also potentially help to retain levels of nutrients that will go some way to achieving a healthy diet.
All views and opinions expressed belong exclusively to Dr Duane Mellor. Funding was provided to Dr Mellor for this time to write this post.