Microbiological quality evaluation of raw materials and animal feed

The microbiological quality of raw materials and animal feed is determined by the presence and quantity of microorganisms. These microorganisms can be to plants and animals, saprophytic, which do not cause lesions, or pathogenic, which do cause lesions.

Dra. Gloria Jauregui - 26/09/2022

Microbiological quality evaluation of raw materials and animal feed

The microbiological quality of raw materials and animal feed is determined by the presence and quantity of microorganisms. These microorganisms can be to plants and animals, saprophytic, which do not cause lesions, or pathogenic, which do cause lesions. Microbiological controls are measures that are adopted to reduce the risk of transmission of foodborne diseases. Fungi, virus, and bacteria coexist in the environment with crops, they achieve a balance, and use plants to ensure their survival and dissemination. These microorganisms have different properties to defend themselves against the invasion of other microorganisms. These properties in some fungi and bacteria are called toxins, which are small chemical molecules capable of causing harm to another microorganism. These toxins also cause harm to animals and humans. When the toxins are produced by fungi, they are called mycotoxins.

To ensure the quality of the raw material, one of the aspects to consider is microbiological controls. These are laboratory tests to detect the presence of pathogenic fungi and bacteria. When a raw material is contaminated with a pathogen, it continues to spread out throughout all the food chain. Conditions such as: crop type, crop humidity, heat and ambient temperature, can make different pathogens presence vary. For this reason, it is necessary to establish Critical Control Points to carry out these analyses in each industry.

Microbiological analyses need to be accompanied by information such as the material type, the sampling plan, examination method, and the microbiological limit for accepting or rejecting the raw material. There are various sampling approaches (batch testing, process control testing), but all of them compare the results obtained with established limits. The number of microorganisms is established by each country and for each raw material type.

The microbiological analyses that are carried out are enriched culture media, and later Polymerase Chain Reaction (PCR) to determine strains. There are rapid tests, using the ELISA method. To carry out these analyses, it is very important to take a representative sample of the lot or area to be analysed, since a poor sampling technique can invalidate the results.

The Microbiological results of the analyses are expressed in colony-forming units (CFU) and in terms of presence or absence of a pathogen. The European Union, and most countries, have established limits that are used in all raw materials and animal feed. Animals and vegetables products for human consumption have other limits.

The following are those used in animals:

Microbiological results

When the result of the microbiological analysis is not what is expected, there are corrective methods that can be applied, such as discarding or rejecting a batch, and when the contamination is not potentially harmful, the use of ac. organic or preservatives are an option: the cimenol ring of Alquermold Natural works by perforating the microorganisms’ membranes what it causes their death. It is an animal feed preservative and intestinal biocide. Botanical origin and does not require withdrawal period. It is broad spectrum, including: E. Coli, Salmonella spp., Clostridium spp. Aspergillus spp. and Fusarium spp. It has a long-time effectiveness, up to 6 months. It prevents the secretion of mycotoxins by fungi in animal feed. It promotes the intestinal flora and increases the animal’s productivity parameters.

The importance of analysing the microbiological quality of raw materials and animal feed is an objective reference that influences decision-making. When contamination problems are evident, control and prevention measures can be taken to enhance the feed processing capacity and to avoid the rejection of batches in the supply chain. Many manuals of Good Practices, risk analysis and critical control points in the industry are available to everyone. They detail how to apply microbiological control in different industries.

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