For much of the feed industry – where margins are often low – the question will be how to implement feed safety measures in an effective but also cost-effective way. Meeting ever-growing demand in a sustainable way, means that feed safety will be an increasingly vital topic.
Dr. Edyta MARGAS
Food and Feed Safety Leader/ Gıda ve Yem Güvenliği Müdürü
Feed safety is a vital issue as the products we feed to animals ultimately are eaten by ourselves. While the feed safety sector has traditionally evolved more slowly than food safety – as the products are not sold directly to the final consumer – a number of widely reported events (BSE, foot and mouth disease, antimicrobial resistance, veterinary drug residues and outbreaks of food-borne bacterial infections) have led to increased public awareness of the issues. Due to these events, legislation became one key driver of the change towards increasing feed safety standards. A knock-on effect is that there is increasing pressure from larger retailers and big brands, some of whom now have their own feed safety specifications. These developments force feed producers to steadily improve their feed safety standards.
COMMON FEED SAFETY ISSUES
The main issues regarding feed safety are contaminations of raw materials with mycotoxins or heavy metals, contaminations with product residues and microorganisms like Salmonella. Some raw material contaminants like heavy metals, pesticides, chemicals or drug residues cannot be removed through processing, which is why sourcing and testing of raw materials are essential.
In the feed mill, another significant potential safety risk is the introduction of hazards during handling, processing, storing, and transportation. Here, the main focus is on the prevention of contamination with microorganisms and unintentional ingredients, which mainly come from other feed products. The introduction of these hazards occurs due to “cross contamination”, which is the unintentional transfer of microorganisms, ingredients, chemicals or other components from a source to a product. As a result, contaminations which were not present in the raw material can be found in the final product.
To avoid cross contaminations the production line have to be flushed after the production of a recipe to remove residues, for example with corn or wheat. Using this method, the amount of product used for flushing is critical to completely fill the pipes and equipment and remove product residues. A safer approach is the sequencing of recipes additionally to flushing: after a detailed analysis of all recipes and its critical components, the production is planned so that potential cross contaminations are not harmful to the animal consuming the feed produced afterwards. For medicated feed – the most critical example – completely separated production lines are used. To minimize the general risk of cross contaminations the plant layout and hygienic design of the equipment is crucial, and spots where product and dust can accumulate have to be avoided. But also a well-designed plant has to be cleaned and the equipment checked at regular intervals in order to prevent the accumulation of product residues. Therefore, cleaning and maintenance plans have to be established and precisely followed.
PATHOGENIC MICROORGANISMS WITH FOCUS ON SALMONELLA
Several pathogenic bacteria can be found in animal feed, but the control of Salmonella in feed has been a particular priority for feed producers for decades. The reason for this is that Salmonella it is the pathogen mostly associated with feed and dry food safety incidents.
To control Salmonella, the most efficient way is to take a similar approach to that currently applied in the food industry. The first step is ensuring that properly handled raw materials are inspected and tested on arrival, with an action plan in place for when Salmonella is detected. The second is to keep the moisture level of the feed and processing environment low and stable, with controlled conditions during storage, hygienic design of machinery and appropriate drying or cooling for incoming raw materials and after pelleting. One important factor is the prevention of condensation, for example through heating mats and hot air drying in the process line, as the condensation offers perfect conditions for the growth of molds and bacteria.
As a certain level of contamination of feed materials with Salmonella and other pathogens cannot be prevented, a reliable “kill step” for decontamination is needed. This is done with a thermal processing step such as conditioning and retentioning, which is comparable to the pasteurization of milk. The optimal treatment should be designed to ensure a safe process while maintaining top quality standards and nutritional value of the product, as feed contains several heat-sensitive ingredients. Therefore, efficient heat treatment consists of a finely tuned interplay between temperature, moisture and time. To establish most suitable conditions for heat treatment, validation of the process is necessary. Only by conducting validation studies, ideal conditions are established to ensure sufficient kill of bacteria and at the same time, efficient process and high quality product. Following this kill step, taking care to avoid recontamination during processing and handling is vital, and depends on effective factory zoning and separation of materials, as well as hygienic design of the equipment.
A warm and humid climate during cultivation, as well as poor storage of crops, allows some common fungal molds to grow which can produce dangerous levels of so-called mycotoxins. The most studied, and currently the only mycotoxin for which there are legal limits for animal feed as well as food, is aflatoxin. A potent carcinogen, aflatoxin can also be passed to humans via milk from cows that have consumed contaminated feed. Other mycotoxins are also beginning to play a key role in feed safety. It is recognized that for example DON, Zeralenon or Ochratoxin can have negative effect on animals and are present at significant levels in feed materials.
In general, long term exposure to mycotoxins can lead to cancer, but adverse effects can also be visible in animals within a short time frame. These include reduced feed uptake, increased feed conversion rate and reduced resistance to infections, increasing the need for antibiotics.
Mycotoxins cannot be reduced in thermal processes as they have a high heat stability. Testing of raw materials at the intake to detect affected crops and ensuring good storage conditions are the main approaches to reducing risk. However, mycotoxins mainly appear in hot spots and are not homogeneously distributed in one batch, so negatively tested raw material can still have significant contamination levels. To reduce contamination levels in feed, grains can be cleaned by sieving, aspiration or gravity separation. These methods significantly reduce mycotoxin concentrations, as the highest concentration of mycotoxins can be observed on the grain surface, in broken grains and in dust. Another approach is the removal of contaminated grains by optical sorting. The cameras installed in optical sorting machines detect and remove grains with visible signs of mold growth, such as dark spots or shriveled, discolored or broken kernels, resulting in a high quality product with minimal contamination levels.
FEED SAFETY – SOLUTIONS OF THE FUTURE
Along with the growing meat demand, the standards and requirements of the food industry will increasingly be seen as targets to aim for also in the feed industry. For much of the feed industry – where margins are often low – the question will be how to implement feed safety measures in an effective but also cost-effective way. Meeting ever-growing demand in a sustainable way, means that feed safety will be an increasingly vital topic.
The implementation of effective feed safety solutions will require active collaboration between producers and technology suppliers. There is huge potential in the field of digitalization for accurate product traceability and improved equipment performance, as well as monitoring crucial parameters such as temperature, moisture and humidity. Advances in data analysis will also create huge opportunities for evaluation of risks and development of control measures. The coming decades are therefore likely to see feed safety evolve beyond recognition.
We also suggest you to read our previous article titled "Reducing Salmonella Effect in Poultry".