Washington State University researchers have developed a method of preserving and packaging ready-to-eat foods, such as macaroni and cheese, that could triple shelf life from one year to three years. Their study was published in the journal Food and Bioprocess Technology.
The mac and cheese was put in special metal oxide-coated high-barrier polymer packages and preserved using microwave-assisted thermal sterilization. Microwaves won’t work with metal cans, and glass is too fragile and heavy for military or space uses, according to a WSU release.
U.S. Army tasting panels decided the mac and cheese tasted fine after being stored at 100 degrees Fahrenheit for six months, which is equivalent to being kept for three years at room temperature, Shyam Sablani, lead researcher and WSU professor of biological systems engineering, told Food Dive.
This food preservation development, funded by the U.S. Department of Agriculture’s National Institute of Food and Agriculture Research, could have applications for the military, space travel and long-term storage of food for use after hurricanes or other natural disasters.
Previous plastic packaging technologies have typically had problems maintaining a solid barrier between the food and outside conditions. Microscopic cracks would develop, or the plastic would permit gases, including oxygen, “which is the enemy of the food,” or moisture to cross the barrier, Sablani said.
Putting an organic coating over metal oxide helps reduce cracks. More coating layers on the plastic enhance barrier performance, Sabali noted. The overall result has been better high-barrier packaging than could be achieved using other techniques.
Food preservation has a long history and includes a wide range of methods. Dehydration, fermenting, canning, pickling and freezing have been the most common techniques through the years. Each has advantages and disadvantages, and one approach may be more effective with certain types of foods than others. Pickling and water bath canning are better for high-acid foods, for example, while low-acid ones will likely perform better with pressure canning.
Manufacturers processing and sterilizing large amounts of food for retail consumption have relied on autoclave or retort packaging technology, and high-pressure processing, or HPP, to kill microbes and make food safe for consumption. But some claim autoclave and retort technology kill flavor and texture along with microbes. The U.S. Food and Drug Administration has questioned whether HPP adequately handles the risk of Clostridium botulinum in low-acid juices.
HPP is in wide use today to process plant-based beverages, cold-pressed juices, soups, deli meats, ground beef and other food and beverage products, although the technology can be expensive and labor-intensive. On the plus side, HPP doesn’t use heat, retains a fresher taste and more nutrients, and also extends shelf life, so guacamole products keep their original color and taste without darkening.
According to Sablani, conventional heat-based food preservation techniques often use more chemicals to enhance the flavor profile of food items. The retort process tends to destroy flavors and aromas, he told Food Dive, so manufacturers have to develop a balancing act to bring them back.
“To boost that, food companies tend to add a little more salt, so most canned food products have extra salt, which is not good for the health,” he said. “New processing technology such as our microwave can preserve the food and reduce the salt content. That is a positive thing.”
Other universities are researching different food preservation technologies, Sablani said. Ohio State University’s Sudhir Sastry is exploring high-voltage electricity applications to preserve food. This “ohmic heating” method uses a rapid and uniform heat source to kill microorganisms and preserve the food without losing taste. However, this technique is more effective on heat-sensitive products, such as soups and stews or others combining chunks of food with a liquid base.
Aseptic carton packaging, such as the containers made by Tetra Pak, is still another way to preserve foods and beverages. This process helps manufacturers reduce waste and extend product shelf life without refrigeration for six to 12 months. And while that’s less time than the oxide-coated polymer packaging WSU has developed, it does allow longer shipping and retail sale windows before items expire or lose flavor, texture or nutritional benefits.
A survey earlier this year from L.E.K. Consulting found 75% of 250 brand owners in the CPG industry expected to hike spending on packaging during the next year. That’s up from each of the past two years, the company said, when 65% in 2018 and 40% in 2017 said they would be doing so.
However, spending more on packaging might not deliver an larger customer base and more market share unless the food or beverage inside is preserved adequately, safe to eat, tastes good and delivers nutrients and other qualities as advertised.
Some food makers are aiming to meet all of those goals with new ingredients. Lamb Weston has come up with a french fry batter to keep its fries crispy for 12 minutes. This isn’t much in terms of shelf life, but it’s more than twice the standard five minutes within which the product can get soggy and lose its appeal. For McDonald’s and other brands on the lookout for a better and more stable french fry, this application could make the difference for consumers.
An innovation from Ingredion helps keep the texture in processed meats and can extend the shelf life of pastries and breads. Made from potato fiber, the company’s Potex product limits stickiness and helps increase yield, reduce waste and enhance freshness for longer periods. And General Mills has patented a flour-milling process to add another month on to the refrigerated shelf life of raw dough products, extending it from 90 to 120 days.
Given today’s on-trend demands, food and beverage manufacturers have to stay current on processing and preservation technologies. Consumers are looking for flavor, freshness, nutrients, shelf appeal and reasonable prices, as well as convenience and portability — and they also want transparency and clean labels. It’s a challenge for manufacturers to make high-quality, convenient and inexpensive food with minimal ingredients, so typically something has to give, whether it’s price, taste or perhaps the product’s “natural” credentials.
Sustainability is another growing concern for consumers who want to reduce packaging, and compost, reuse and recycle anything they can. Sablani acknowledged “a solid waste problem” with the new packaging plastic he and the research team members are developing.
“It is not biodegradable, so one research area is to develop biodegradable plastic using plants and not synthetic crude oil,” he told Food Dive.
These plant-based solutions would be based on starch, he added, and any type would work as long as it’s inexpensive and not used for human consumption.
Processing and preserving other recipes are also on his research agenda. These include chicken pasta, sweet potato puree and garlic mashed potatoes, which need a longer shelf life for storage and eventual consumption in the field. The items also must have complete nutrition and a good balance between carbohydrates, protein and fat, Sablani said, and contain enough vitamin C and E following processing.
Most important is that the packaged RTE foods appeal to the astronauts, disaster survivors or troops for whom they’re designed.
“When soldiers are fighting in a battlefield, they are marching, and there is no restaurant to compare [ready-to-eat meals] with,” he said. “The question is whether you like it or not, and are you going to eat it or not. You have to take it in that sense.”