The US Food and Drug Administration (FDA) is currently investigating certain petfoods that are suspected to contain dangerous levels of aflatoxin for animal consumption. The Sunshine Mills recall includes petfood that was distributed both within the US and Japan and Colombia. However, analyses and studies on its residues and the susceptibility of animal species (especially for domestic, swine, bovine and poultry species) on the toxicity of aflatoxin date back to 1960.
Petfood formulas include raw materials such as corn, soybeans, rice, wheat, and poultry, cattle, and fish. Many of these raw materials, mainly those of plant origin, are susceptible to fungal contamination that can lead to the production of mycotoxins. Mycotoxins are a group of secondary metabolites produced by various filamentous fungi that can cause harm if ingested.
In this case, aflatoxin is a type of secondary metabolite (mycotoxin) produced by certain species of fungi. It is highly toxic and carcinogenic (for both animals and humans), and more for dogs than for other animals, and is found in agricultural crops like corn, peanuts, and hard-shelled nuts, such as walnuts, among others. The fact that they are a secondary metabolite means that they are not necessary for the growth or reproduction of the fungus. In fact, not all fungi are capable of producing mycotoxins. The main aflatoxins (AF) consist of aflatoxins B1, B2, G1 and G2 produced by certain toxigenic strains of fungi Aspergillus flavus, Aspergillus parasiticus and Aspergillus nominus.
If present in high levels in food, aflatoxin can cause disease in animals, and even lead to death. The most common symptoms are loss of appetite and energy, vomiting, jaundice, and diarrhea. Animals that show few symptoms can even suffer permanent liver damage.
Several studies carried out lead to the same result: diets with concentrations higher than 60 μg / kg (micrograms per kilo) of aflatoxin B1 can already cause aflatoxicosis, the disease caused by the consumption of aflatoxins. However, it always depends on each animal and its general state of health, as well as factors such as age and hormonal and nutritional status.
Pregnant and young animals have been found to be the groups most susceptible to aflatoxin B1 toxicity. It has been claimed that, although the production of contamination can occur after harvest under improper storage conditions, large-scale contamination usually occurs in the field itself.
There are even many toxigenic fungi that produce mycotoxins only under specific environmental conditions in terms of humidity and heat: grains stored with a high degree of humidity (> 14%) at warm temperatures (> 20 ° C) can become contaminated.
These conditions allow what are known as “hot spots” to occur in stored grain and become contaminated with aflatoxin. Although, traditionally, mycotoxin-producing fungi have been divided into two groups: “field” (phytopathogens) and “storage” (saprophytes).
The secondary toxic metabolites of fungi can represent a significant risk, both for human and animal health, if the grains used to make feed (or the animals used have been fed with these grains) are colonized by toxigenic fungi.
Preventive strategies to avoid aflatoxin contamination
Reported and recalled batches of food have reaffirmed the need for industry manufacturers to dedicate more resources to certify the quality of the raw material used for production. The challenge that arises is that it must be certified that all products and raw materials within the chain, from what the cow or pig consumed, must be verified as free of carcinogenic mycotoxins.
Consequently, most companies in the US have already increased the control of selection and supply of ingredients used in petfood: a mycotoxin control program from field to table must include critical control points, This will require experts in the interaction of toxigenic fungi with crop plants, their methods of reproduction, harvesting, and current (and optimal) storage conditions to prevent spread.
Aflatoxin in food in Latin America
In Latin America, aflatoxins have been detected as natural contaminants in a large number of agricultural products and in almost all staple foods. In this geographical area, aflatoxins have also been found in oilseeds such as sunflower and soy and in unrefined vegetable oils.
The level of concentration of aflatoxins accepted in food varies according to each country and its way of legislating; however, certain similarities and trends can be found between the European Union, the Association of Southeast Asian Nations and MERCOSUR.
This has been done in order to harmonise and facilitate international trade.
In Latin America, a high incidence of aflatoxins has been found, especially B1 in agricultural products such as corn, rice and peanuts, among others. And, although there are regulations that regulate the amount of mycotoxins, we need to reinforce them with mandatory resolutions that specify concentrations according to group and type of food, frequency of consumption and population risk, both in animals and humans.
Currently, aflatoxin decontamination methods include physical, chemical and biological methods and are often used in combination when food and feed are already contaminated in order to eliminate or at least reduce toxicity. The most used method in the last 30 years has been HPLC or high performance liquid chromatography.
The application of a traceability and control plan ‘from farm to the table’ is necessary for not only each of the products and raw materials involved in the animal feed that reaches the mouth of pets, but it is also required specific knowledge of each of the stages in order to know their risks.
To evolve and improve, it is essential to have reliable analytical methods for the detection and quantification of aflatoxins in food.