Key points
Nutritious, non-perishable foods such as UHT milk are stepping up to help tackle some of today’s biggest challenges.
The food industry is doing its best to meet these many-faced demands, but the challenges are significant – and raising some tough questions about the environmental footprint of food and beverages. How can we meet demand for fresh, perishable foods while still minimising food waste?
How can we ensure food freshness and safety while minimising packaging and the environmental damage it can cause? How do we reconcile the growing need for cold chain logistics with concerns about energy consumption and carbon emissions? The list goes on.
The processing upside
Ulrich Rolle is Head of Product Development – Hygienic Processing at GEA. With over 30 years of dairy industry experience, Rolle spends a lot of time with customers in GEA’s test centres perfecting production processes for their sensitive foods and beverages to optimise safety and efficiency – as well as taste and consistency. Among his obsessions: developing industrial solutions capable of reproducing the quality of grandma’s recipes. He sees no contradiction there.
“Processing food and beverages is essentially about scaling – being able to make and reproduce food safely and reliably in large volumes for large numbers of people. Today’s health-conscious consumers have become wary of ‘processing’, but there’s no reason that scaled food can’t also be healthy,” says Rolle. “In fact, processing food has a long list of environmental benefits – and getting fresh, unprocessed food to large numbers of people has a bigger footprint than many might realise.”
For starters, fresh food and beverages are perishable, so without appropriate processing and packaging, food becomes less safe – and more lands in the bin. Food waste, as it turns out, has a huge negative impact on the environment. The “Food wastage footprint” study by The Food and Agriculture Organisation of the United Nations reveals that the carbon footprint of wasted food is roughly 3.3 Gtonnes of CO2 equivalent.
If “food wastage” was a country, it would rank third in emissions behind only the USA and China. As the study points out, uneaten food also wastes huge amounts of arable land (nearly 30% of the world’s agricultural land area), consumes a huge amount of the Earth’s fresh water resources, and has a significant negative impact on biodiversity.
In the case of milk production, farmers and dairy processors frequently struggle with fluctuations in supply and demand. Over-supply is a real challenge and often means operators must dump milk. “When this happens, it’s not just the milk that is wasted – you also lose all the inputs that went into making that milk, which includes feed, water, medicine, farm labor, machine costs, and so on,” says Rolle. “It’s even more tragic when you consider the food shortages and malnutrition around the world.”
Enter UHT
Ultra-high temperature (UHT) milk processing offers a solution to today’s complex needs. It takes a natural, nutritious beverage – raw milk – and processes and packages it in such a way as to ensure a very long shelf life at ambient temperatures, with no preservatives added.
UHT is one of four basic types of milk: Raw fresh milk involves the least amount of processing; it’s not heat treated, retains its pathogens and therefore has a relatively short shelf life – normally one to three days. “Some people prefer the taste and full nutritional value that raw fresh milk provides,” says Rolle.
“They’ll often have to buy direct from the farmer, since many countries do not allow the sale of raw milk in stores due to safety issues.” Pasteurised milk – the kind most of us grew up with – is heated up to 72 to 75 degrees Celsius for a duration of 15 to 30 seconds, has a shelf life of roughly 12 to 20 days from the time of packaging and requires refrigeration.
Extended shelf-life (ESL) milk also requires refrigeration after packaging, but achieves a shelf life between 21 and 45 days by removing or inactivating the bacteria in the milk before bottling. “Removal can either be done mechanically with bacteria-removing clarifiers or microfiltration, or by using ultra-pasteurisation at a temperature of around 127 °C for four seconds to inactivate the bacteria,” explains Rolle. “These methods can also be combined.”
UHT milk (a.k.a. ultra-high temperature pasteurised milk) is heated to at least 138 °C for two to four seconds, inactivating all bacteria and making it sterile. To ensure product stability, the milk often undergoes high-pressure homogenisation before the heat treatment.
The milk is then filled aseptically – in air-proof, light-proof and sterile containers. UHT milk does not require refrigeration until it is opened; until then, it enjoys a shelf life of six to nine months when kept at ambient temperatures of between 20 to 30 °C.
The nutritional profile of UHT milk is promising: “UHT milk has the same caloric and calcium amounts as raw milk, but slightly less folic acid, vitamin B12, vitamin C, thiamin and iodine, which is also true of pasteurised milk,” says Rolle. “These losses are typically kept to below 20% and can be offset by re-adding vitamins.”
More shelf-life for more sustainability
UHT is essentially the newest generation of milk in different global regions. The nutritional qualities are the same as familiar pasteurised milk, but the added degree of sterilisation, combined with aseptic packaging, means a long list of modern-day benefits related to cost efficiency, food safety, food security, and sustainability. Once processed and packaged, it can be stored under ambient temperatures for several months.
This fact alone has a number of important implications. “UHT milk can provide greater stability in an industry that is often fraught with instability,” says Rolle. “If milk demand hits a low, another market can be found or it can wait until demand picks up again. Certainly for retailers, who generally have tight margins, not having to repeatedly throw away unsold milk that has passed its sell-by date is an important benefit.”
UHT milk also reduces the need for cold supply chain systems, which are expensive, consume large amounts of energy and generate significant amounts of GHG emissions. “Refrigerant gases such as fluorinated hydrocarbons (HFC) are in fact vastly more potent than CO2 as greenhouse gases,” says Rolle.
UHT reduces the need for refrigeration on multiple fronts: in production, transport, and retail stores – but also in people’s homes, where multiple containers of UHT milk do not take up precious space in the refrigerator.
“Shelf-stable milk at ambient temperatures means big environmental benefits, but it is also a critical weapon in the fight against global hunger,” says Rolle. “In countries lacking end-to-end cold chain networks, UHT milk is a nutritional lifeline.”
As of yet, public awareness for the many benefits of UHT has not caught up to the reality. “When most people go to the store, they don’t associate room-temperature UHT milk with all these benefits; they just want to see their milk in the refrigerated section.” The bias is strong enough, says Rolle, that some soy-milk product manufacturers actually pay US supermarkets to have their shelf-stable products sold in the refrigerated section.
“Fun fact: nearly all organic milk in the U.S. is actually UHT, yet still kept in coolers because consumers have concerns about buying warm milk,” says Rolle. “Of course, this is unnecessary and will hopefully change with greater awareness and focus on the environment.”
The shift is happening, if gradually. According to Euromonitor International, around 34% of liquid milk consumption today is shelf-stable or UHT milk. Though retail volumes are currently dipping in North America and Western Europe (the largest market), consumption of UHT milk is on the rise in Asia Pacific, Australia, Eastern Europe, Latin America, the Middle East and Africa.
Not all processing is created equal
Meanwhile, Rolle and his colleagues at GEA continue to make the UHT process more efficient and green. “GEA has more than 125 years of liquid dairy processing experience, so we understand milk, understand the value and benefits of milk processing, and we’ve been working for decades to streamline these processes for greater cost and resource efficiency,” says Rolle.
GEA’s inline UHT process solutions, for example, integrate separation, standardisation and the aseptic process treatment, which reduces fixed and variable costs, especially for energy consumption. For Rolle, another way to optimise efficiency is being close to the customer and matching solutions to their true needs.
“Our customers can choose from three different UHT plant types, which include options for either direct or indirect heating; we tailor this to match their product and process requirements, plant layout and throughput. We also offer customers the opportunity to test processes with our UHT pilot plants, either at a GEA test facility or at the customer’s own production site.”
With processing carefully designed to ensure sterilisation of the UHT milk, aseptic filling becomes a critical step in the process. “This is another aspect that tends to get overlooked. Aseptic filling is critical to ensuring all these important characteristics of UHT related to safety, quality and shelf-life,” says Massimo Nascimbeni, GEA’s Product Manager for Blowing & Filling Technology based on his 12 years of expertise in the beverage filling business.
“It’s also another area where we can have a real impact on overall sustainability.” GEA’s Whitebloc Filling System Aseptic is specifically designed for the dairy industry and for use with PET and HDPE bottles. “The beauty of PET bottles is being able to work with preforms. This not only minimises the amount of plastic required, but also other process materials and resources.”
The GEA Aseptic Blow Fill System ABF 2.0 sterilises the preforms, rather than finished bottles, which are then blown with sterile air – a method that minimises the use of chemicals, eliminates the need for bottle rinsing, and allows for a simpler, smaller layout while reducing energy consumption.
GEA Whitebloc:
Dynamic duo: UHT and PET
PET plastic, as it turns out, also has numerous advantages over other packaging types. “PET provides excellent barrier properties necessary for meeting the food safety requirements for sensitive beverages,” explains Nascimbeni. “It’s the optimal packaging material for liquid dairy and it is significantly growing in this market thanks to the fact that it’s 100% recyclable.”
Indeed, LCA (life cycle assessment) studies show that PET performs better than glass bottles – and even cartons and cans – across a range of environmental issues, including global warming, ozone depletion, fossil fuel use and water consumption. For consumers, it is also perceived as easy to use, rinse and recycle.
It is shatterproof, which helps reduce food waste, and lightweight, which helps reduce transport costs and fuel consumption. “PET has an image problem, a bit like UHT, but it’s actually another important ally in tackling today’s big-picture challenges related to food safety, food security, climate, recycling, and so on. And with the option of bio-derived PET, it’s a real candidate for the circular economy of the future.”
The big-picture choice
Looking ahead, Rolle sees demand for UHT increasing. “Beverage consumers want convenience, which likely means an increase in UHT milk drinkers,” says Rolle. “UHT also tends to be less expensive than fresh or pasteurised milk and once people switch to UHT milk, it seems they rarely switch back.”
Beyond cost and convenience, UHT milk also seems to align with many of today’s mega-trends – urbanisation, e-commerce and a growing eco-consciousness.
“As more people flock to cities, even fewer will have access to fresh milk. Urban populations are likely to shop on foot, by bike, scooter or public transport, which could be problematic for sensitive foods, like dairy products,” says Rolle.
“Of course if they order online, their food will likely be in transit longer and without refrigeration – all factors, incidentally, that also favour lightweight PET packaging.” As awareness grows for the environmental benefits of UHT, consumers may come to regard it as the “greener” choice.
“Then there’s global warming. I hope it’s not the case, but if the planet heats up, it could make fresh and pasteurised milk a less practical option for consumers in some parts of the world,” says Rolle.
And finally Covid: “The lockdowns and restrictions we’ve seen are a stark reminder that having access to non-perishable foods isn’t merely a luxury, it’s an absolute necessity.”
