From waste stream to alternative protein – Preserving food by-products for animal feed

High-moisture by-products generated by the food industry are abundant and rich in nutrients. However, these perishable ingredients present challenges when it comes to storage, transport, handling, and utilization on the farm. Implementing a multi-step process that spans every phase of the by-product lifecycle can help mitigate these challenges.

From snack foods made with insects to cultured meat grown in a laboratory, alternative proteins are emerging as viable sources for meeting dietary demands while preserving the planet’s limited food production resources. A promising approach to solving the protein production dilemma focuses on repurposing by-products from human food for use in animal feed production. Around the globe, stakeholders in the food chain ranging from breweries and bakeries to food traders and farms are discovering ways to convert food by-products from the waste stream into nutritious protein sources for use in livestock feeds.

While the concept of using food by-products is not new, stakeholders’ knowledge about how to practically implement this process has been limited. Most food by-products start to deteriorate quickly, reducing nutrient value, palatability, and, most importantly, the safety of the foodstuffs.

However, like many aspects of food production, science is introducing innovations to help manage these challenges and make preservation of by-products practical. Multiple studies conducted by Selko, the feed additive brand of Nutreco, have shown that highly potent buffered and non-buffered organic acid blends can preserve valuable nutrients in high-moisture by-products.

Selko has a long legacy of researching the mode of action that underlies organic acids’ efficacy in animal nutrition. Multiple studies have provided insights to help develop products with demonstrated efficacy in inhibiting microorganisms, such as yeast, bacteria and moulds, and extending the shelf life of by-products and finished feeds. Below, we look at the scientific and practical aspects of collecting and reusing by-products for use as alternative protein sources.

MANAGING MICROBIAL RISK IN HIGH-MOISTURE PRODUCTS
High-moisture by-products generated by the food industry are abundant and rich in nutrients. However, these perishable ingredients present challenges when it comes to storage, transport, handling, and utilization on the farm. Implementing a multi-step process that spans every phase of the by-product lifecycle can help mitigate these challenges. A holistic approach to preserving by-products for use in animal feed should include recollection, treatment, transport to feed producers’ facilities, and eventual storage and handling on the livestock farm. Adequate management measures are essential to achieve feed quality and safety objectives. Factors that must be considered include microbial diversity, spoilage mechanisms, and the application of validated preservation techniques using specific organic acids. A proactive and carefully considered approach to logistics can help preserve by-products for use as alternative protein sources.

The food industry produces significant quantities of high-moisture by-products, including, but not limited to, fruit and vegetable pulps, dairy whey, and brewery spent grains and yeasts. Sadly, much of this food goes to waste. In fact, the U.N. Food and Agriculture Organisation has reported that one-third of food produced – about 1.3 billion tons – is lost in the food chain. While some of that waste can be recollected and used for animal feed, by-products are highly susceptible to microbial spoilage and must be properly treated to protect ingredient safety. There are also logistical challenges that must be managed across every phase of the lifecycle, starting with the production facility.

By-product lifecycle assessment #1: Production Facility
A producer of high-moisture food by-products – typically a brewery/distiller, dairy processor, fruits and vegetable processing plant, or some other production facility – is the first point of contact for introducing preservation efforts. Treatment starts with the application of preservation products, like Revalet. The goal is to inhibit microbial proliferation and preserve nutrient quality. In developing the Revalet preservation product, Selko scientists relied on potent blends of buffered and non-buffered acids known to exhibit antimicrobial properties against a broad spectrum of microorganisms, including bacteria, yeasts, and moulds.

Measurement is essential for management, so the status of by-products must be assessed prior to treatment. Some assessment metrics include the by-products’ pH, moisture content, nutrient composition, and microbial load. The assessment helps to determine the appropriate product and inclusion rate required for an effective treatment on a given by-product.

At the production facility, Revalet is generally applied to by-products through dedicated dosing systems that mix the product directly onto the by-product process lines before the final storage tank. Treatment at food production facilities may include inactivation of microorganisms used on biotechnology processes (i.e. fermentation). Revalet is commonly used for inactivation and microbial growth inhibition on the by-product. The treatment time may vary depending on factors such as the microbial count, temperature and pH of the by-product. Monitoring and quality control measures should be continued throughout the treatment to assess the efficacy of treatment and ensure the safety and quality of the treated by-products.

Lifecycle Assessment #2: Trader companies
Trader companies source high-moisture by-products, not always treated previously, at food production facilities. During the by-product recollection process, attention must be paid to factors such as freshness, hygiene, and initial microbial contamination levels to ensure the quality of the incoming by-products. The high-moisture by-products are transported from the producer to trader company facilities using specialised vehicles equipped with refrigeration or temperature control systems to maintain freshness and prevent spoilage. Upon arrival at the trader company’s facilities, these products undergo a precise treatment protocol to control microbial growth and enhance shelf life. Selko’s quality assurance and preservation experts can provide tailored guidance to adjust treatments.

Lifecycle Assessment #3: Animal feed producers
Upon arrival at the animal feed production facility, by-products are again inspected for quality. Food by-products quality checks usually include visual appearance, odour, dry matter and microbial load. At this stage, depending on the by-product’s source, whether it be traders or directly from the food producers, by-products undergo further treatment with Selko products to help maintain their nutritional value and palatability. Additives such as vitamins, minerals, and enzymes may be incorporated into the by-products to meet specific nutritional requirements and support animal health and performance. The treated by-products are then mixed and blended with other feed ingredients to create feed premix formulations. Collectively, these processes contribute to the sustainability and efficiency of animal agriculture by utilising valuable by-products from the food industry and applying them to feed production.

Lifecycle Assessment #4: On the farm
Managing and utilising feed premixes derived from high-moisture by-products directly on the farm involves careful handling, storage, and application to ensure the diet delivers optimal nutrition and supports animal health. Incorporating specially selected organic acid blends in feed premix formulations plays a crucial role in conserving quality, reducing nutritional spoilage, and enhancing microbial control.

Below is a playbook of on-farm processes that support by-product treatment:
a. Storage and handling: Upon delivery, feed premixes should be stored in designated areas under controlled conditions to prevent exposure to moisture, sunlight, and contaminants.

b. Feed premixes can be incorporated into moist feed systems used to feed livestock, such as swine or ruminants. Conditions are different on every farm, so it is important to apply proper treatments for a given situation. Appropriate additives are added to moist feed formulations to inhibit microbial growth, preserve nutritional integrity, and extend shelf life. Feed premixes are then carefully mixed with other feed ingredients, such as crushed grains, molasses, other by-products, and supplements, to achieve the desired nutrient composition and consistency.

c. Including preservative products in animals’ feed premix and final feed helps to lower the pH levels in feed, creating an environment unfavourable for harmful microbial growth and reducing the risk of feed spoilage. Selko additives are designed to act as potent preservatives, extending the shelf life of feed formulations.

Preserving food by-products for use in animal feed can reduce use of landfill. This practice can also open up new feed ingredient options for regions of the globe where traditional protein ingredients may be in short supply. As an overlooked “alternative protein,” properly treated food by-products can help optimise the allocation of resources used in food production and play a role in feeding the future.

An integrated strategy support to a more circular approach

Given the multiple phases involved in the food by-products life cycle, Feed & Additive magazine wanted to know about how an integrated strategy can support ingredient quality and stakeholders’ efforts to create a more circular approach to protein utilisation. Below are excerpts from a conversation with author Andrea Lopez, Global Product Manager at Selko.

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What opportunities and challenges do food producers face when it comes to managing high-moisture by-products like dairy whey, fruit and vegetable pulps, and brewery spent grains and yeast?
High-moisture products are utilised every day in various production processes and in food and beverage businesses. A perpetual stream of high-moisture ingredients is available in by-products and can be put to good use in animal feed, as opposed to ending up in a landfill or as biogas. However, the high level of moisture in these by-products can make it quite difficult to preserve the nutritional value so that the feed maintains its shelf life and nutritional value.

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How can stakeholders across the food chain manage these challenges?
It’s essential to create a wise logistics strategy. A plan needs to consider the best time to pick the by-products up, the best means to transport them to the trader company, feed premix facility, or farm, in the proper conditions. Preservation products applied to by-products at any stage of the process can help reduce microbial proliferation, inhibit the deterioration of by-products, and preserve nutritional quality.

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How is ingredient quality managed across the by-products journey?
I’ll share an example from the Netherlands, where we pay close attention to the life cycle of by-products as they travel from the producer to the food traders to the feed mill or premix facility and eventually to the farm. As perishable ingredients age and conditions change, monitoring must be consistently carried out. By assessing ingredients at each point, we can determine the proper Revalet or Selko products to introduce the specific inclusion level. For example, we can see how much of the treatment product is needed to inactivate yeast development at a producer’s location. When ingredients arrive at the food-or, by-products traders or feed producers, it may be necessary to add other Selko solutions to maintain the nutritional value and decrease the microbial load. Additional treatment depends on whether ingredients were previously treated at the food producer’s facilities or if they come directly from food processing. More adjustments may be needed to deal with challenges at the farm, like biofilm levels in the pipes of liquid feeding systems.

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How does preserving by-products benefit participants across the distribution chain?
Workers at trading companies, feed premix facilities, and on the farm are all very busy. While it’s true that you can’t buy time, proper treatment of ingredients can allow more time for a product to be kept in transit or storage and still maintain its nutritional value and other attributes like palatability and dry matter levels.

We also should be mindful of production regions that may not have ready access to ingredients. Again, treating by-products with preservatives provides a workable way to get animals the high-protein ingredients necessary to achieve production goals.

And, finally, if we can put materials that would otherwise end up as landfill or biogas, to use in animal feeds, we can reduce the amount of natural resources required to produce protein ingredients for livestock production.

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Do different phases of the ingredient life cycle present more challenges when it comes to preservation?
The conditions on a farm are typically different than the conditions in a production facility or during transit. For example, varying levels of heat, humidity, or ventilation in the environment should be considered to ensure that products maintain quality and nutritional standards until they are consumed by the animal.

At Selko, we’ve done studies to understand which specific organic acids and inclusion rates are most effective at treating different by-products in different conditions and life cycle stages. Data from these studies can help by-products traders, feed premix producers, and farmers evaluate the best approach to achieve a good return on investment.

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What species can consume feeds made with by-products?
Brewer’s yeast by-products are particularly well suited for liquid swine feeds. Similarly, molasses is a good ingredient for liquid feeds used in ruminant nutrition. As a research-driven organisation, Selko is investing in studies to understand how the preservation of by-products can lead to more innovation in animal feed for a range of aquaculture. Some industries – like aquaculture – are more challenging than others, but there is an opportunity to build on the successes we’ve seen with by-product use in swine and ruminant nutrition.

About Andrea Lopez
Andrea Lopez is Selko’s Global Product Manager for Yeast Control and Food2Feed program. She is a dynamic professional with a background in biotechnology and a wealth of experience in sustainable practices within the food and feed industry. Her work experience has been dedicated to implementing sustainable solutions that optimize the utilization of by-products as alternative protein and nutrients sources, replacing common raw materials used in animal feed.
Currently, Lopez serves in a pivotal role focusing on the application of organic acids for nutritional preservation and microbial control in high moist by-products. As an integral member of the team, she spearheads initiatives aimed at harnessing the potential of organic acids to enhance the nutritional quality and safety of these by-products when used on animals. Her dedication to addressing environmental concerns while promoting nutritional preservation underscores her commitment to shaping a more sustainable future for the feed and food industry.