Introduction
Animal feed is a cornerstone of the global food industry, playing a crucial role in enabling the sustainable and safe production of food of animal origin across the world (FAO, 2020). Despite its importance, feed hygiene remains one of the most neglected aspects within the animal nutrition and feed sector. Ensuring feed safety and nutritional quality of animal feed is vital for the overall health and performance of animals, directly influencing their well-being, growth rates, and farm profitability.
Feed hygiene refers to the practices and measures taken to ensure that the animal feed is free from contaminants such as bacteria, molds, toxins, and other harmful substances (FAO, 2020). Several factors influence feed hygiene such as microbiological causes like bacteria, parasites, prions, viruses, chemical causes like residue of heavy metals, pesticides, mycotoxins, PCB, dioxins, fertilizers, disinfectants and physical causes like soil, sand, dust, toxic plants, or banned feed ingredients (Hoffmann, 2021). The quality of feed directly affects animal well-being, growth rates, and overall farm profitability. Feed hygiene requires control throughout the feed production chain but the feedstuffs’ safety can rarely be certified or verified due to the wide range of potential contamination agents and hazards encountered in different feed environments(Johan den Hartog, 2003).
Table: Hazards in the feed chain
| Biological | Chemical | Physical |
| Bacteria | Naturally occurring Toxins | Metal parts of equipment |
| Parasites | Pesticides residue | Glass |
| Viruses | Veterinary drug residue | Stones |
| Prions | Potentially toxic residue | Bones |
| Chemical contaminants | Nanomaterial | |
| Environmental pollutants | Microplastics | |
| Radionuclides |
(Source – FAO, 2020)
Feed hygiene
In order to ensure the wellbeing, health, and productivity of animals as well as the safety of products derived from animals that are intended for human use, feed safety and feed hygiene are critical. The relationship between feed and microorganisms varies where feed can transport pathogenic microorganisms directly and transmit disease; likewise, microorganisms can also be responsible for feed spoilage and thereby indirectly cause issues (Baer et al, 2013). The inclusion of new ingredients such as animal proteins, oils, and fermented products, among others, increases the need for strict feed quality monitoring (Truelock et al, 2020). Moreover, factors such as the type of feed components involved and water activity levels also need to be considered while optimizing feed hygiene (Doyle and Mazzotta, 2000). Ensuring the feed safety and hygiene is quite challenging and involves several checks and balances throughout the entire value chain of feed processing. The deficient feed hygiene can be attributed by four main categories of causative factors:
- Microbial contamination
Pathogens: Feed can be a medium for pathogens such as bacteria (e.g., Salmonella spp, E coli, Listeria spp, Clostridium spp), viruses, fungi, and parasites. These microorganisms can cause diseases in animals, ranging from mild gastrointestinal disorders to severe systemic infections. Salmonella is a gram-negative enterobacter and can occur in feed. There are only two species in this genus, Salmonella enterica and Salmonella bongori (Lin-Hui and Cheng-Hsun, 2007), but almost 2,700 serotypes (serovars), of which around 10% have been isolated from birds. In general, most serotypes of Salmonella can infect several animal species (Gast, 2008), such as Salmonella Typhimurium and Salmonella Enteritidis. The origins of pathogenic E. coli in a flock can also be traced to feed contamination (Stanley & Bajagai, 2022). Another commonly encountered bacteria entered through contaminated feed is Clostridium causing necrotic enteritis and is majorly responsible for slow but steady mortality in growing flock. The presence of these pathogens can lead to gastrointestinal diseases, contributing to mortality rates as high as 30% in affected flock (G.Yu., Laptev et al., 2023)
Mold and Mycotoxins: The molds can grow on improperly stored raw materials and feed, producing mycotoxins (secondary metabolites that are toxic to animals). Common mycotoxins include aflatoxins, ochratoxins, trichothecenes, zearalenone and fumonisins. These compounds can cause digestive disturbances, damage to the reproductive system, liver damage, immunosuppression, and even cancer in animals. These mycotoxins can affect the animal in several ways, from decreasing performance to severe disease (Esmail, 2021; Government of Manitoba, 2023).
2. Chemical contamination
Pesticides: Residues from agricultural chemicals used in crop production can contaminate animal feed. Chronic exposure to these chemicals can lead to various health issues in animals, including digestive disturbances, reproductive problems and carcinogenesis.
Heavy metals: Contaminants such as lead, mercury, and arsenic can accumulate in animal feed through environmental sources, such as soil or water. These metals are toxic and can cause neurological, renal, and hepatic damage.
Feed additives: While additives like antibiotics, vitamins, and minerals are often used to promote growth and prevent disease, improper usage can lead to issues such as antibiotic resistance or toxicity.
- Physical Contaminants
Physical contaminants such as stones, metal fragments, and plastic can cause physical damage to the animals’ digestive systems, leading to injuries or blockages. Ensuring that feed is free from such hazards is crucial for maintaining animal health.
4. Spoilage and Nutrient Degradation
Oxidative rancidity: Fats and oils in feed can undergo oxidation, leading to rancidity. This not only reduces the palatability of the feed but also decreases its nutritional value, particularly affecting fat-soluble vitamins (A, D, E, and K).
Nutrient depletion: Improper storage conditions can cause degradation of essential nutrients, such as proteins, vitamins, and minerals. For example, exposure to light can degrade vitamin A and D in feed.
Importance of feed hygiene
1. Animal health & welfare: Contaminated feed can lead to a range of health issues in animals including gastrointestinal infections, reduced growth rates, and decreased reproductive performance. For example, Salmonella or E. coli contamination can lead to gastrointestinal illnesses, while molds and fungi can produce mycotoxins that are toxic to livestock.
2. Nutrient integrity: Poor feed hygiene can lead to spoilage, reducing the nutritional value of the feed. Contaminated feed may result in nutrient deficiencies which may lead to reduced feed intake and low FCR.
3. Productivity and performance: Poor feed hygiene can negatively impact overall productivity of animals. This can result in deficiencies or imbalances that affect animal growth, reproduction, and overall health.
4. Quality of animal products: The nutritional quality of animal products can be directly influenced by the quality of feed. Poor-quality feed can lead to lower-quality meat, milk, and eggs, affecting taste, texture, and nutritional content of the animal products.
5. Economic impacts: Poor feed hygiene can lead to death of livestock, and decreased production efficiency resulting in economic implications for farmers and the broader agriculture industry.
6. Regulatory compliance: Many countries have strict regulations regarding feed hygiene to ensure better animal and public health. Non-compliance can result in legal consequences and financial penalties. Good feed hygiene practices are often necessary for accessing certain markets, especially for export. This is important for maintaining consumer trust and ensuring the safety of the food supply chain.
Controls measures to maintain good feed hygiene:
Good feed hygiene is essential for maintaining the health of livestock, ensuring food safety, and preventing the spread of diseases. Below are some key control measures for maintaining good feed hygiene:
1. Stringent Selection & Monitoring of Raw Materials
Ensure that feed ingredients sourced from reputable suppliers with stringent quality control measures. Conduct regular testing of feed for contaminants such as mycotoxins, pathogens, and chemical residues. Regular training to all personnel involved in feed production and handling on hygiene practices and the importance of maintaining feed quality.
2. Proper Storage of Feed
To avoid contamination and spoiling, feed and feed ingredients should be stored in dry, clean, and well-ventilated areas. Regular cleaning and sterilization of storage bins, silos. Implement an integrated pest management program to control rodents, insects, and other pests.
3. Feed Handling Practices
Regular cleaning and disinfection of all equipment used in feed production, transport, and feeding. Avoid cross-contamination between different types of feed, especially medicated and non-medicated feeds. The vehicles used for transportation of raw material and feed should be clean and free from contaminants.
4. Biosecurity Measures
Identify potential hazards in the feed production and handling process. Establish and monitor critical control points to prevent or reduce the risk of contamination. Limit access to feed storage and production areas to authorized personnel only. Enforce strict hygiene protocols for visitors and personnel entering feed production areas. Implement corrective actions when deviations from critical limits occur. Dispose of contaminated feed safely and in accordance with local regulations to prevent environmental contamination.
5. Use of Additives
Use approved preservatives (mold inhibitors, natural antimicrobials, antioxidants, and toxin binders) to extend the shelf life of feed and prevent microbial growth. Incorporate probiotics and enzymes to improve feed digestibility and reduce the risk of harmful bacteria.
By following these control measures, we can significantly reduce the risk of feed contamination and ensure that your livestock receive safe, high-quality nutrition.
Conclusion:
Feed hygiene needs to be ensured for successful animal production and public health. Good feed quality can be attained through adhering to essential practices addressing emerging challenges and maintaining high standards of feed hygiene.Feed hygiene needs to be ensured for successful animal production and public health. Good feed quality can be attained through adhering to essential practices addressing emerging challenges and maintaining high standards of feed hygiene.