Which are the Potential Food Safety Risks in Cereals?

Cereal grains are a prominent food source for humans and animals and are grown in many parts of the world. China is the largest producer of cereal grains, with an annual production of over 612 million tons[1]. In 2021, the global production of cereals was reported to be 3.7 billion tons.[2]

To fulfill the high demand for cereal production, farmers must be aware of the risks associated with growing and storing cereal grains. A benefit of maintaining cereal grain health is that they are living organisms with a slow metabolism. Yet, risks can occur in cereal grains before and after harvesting and can be classified under the main food hazard categories; chemical, biological, and physical.

Chemical Risks in Cereals

Artificial and naturally occurring chemical substances, called pesticides, are frequently used in farming to control, prevent or destroy any pests and diseases which may invade crops. To ensure safety, regulations are in place that determine the maximum allowable limits of pesticide residue in both organic and conventional crops.

Mold (fungi) can produce toxic compounds, mycotoxins, most commonly in cereals, dried fruits, and nuts. Mycotoxin exposure can occur primarily by eating contaminated food or indirectly by consuming products, for example, milk from animals that have been fed the contaminated crop. The most prevalent mycotoxins in cereal include aflatoxins, ochratoxins, patulin, fumonisins, zearalenone, and deoxynivalenol.

Another chemical threat is heavy metals, including lead, cadmium, and mercury. Their contamination in cereals may occur in the field or during harvesting, storing, or processing. Commonly, cereals absorb heavy metals from the soil.

Exposure to such chemical risks can result in a range of negative effects on health. These can include acute poisoning, foodborne illness, and long-term accumulation of the side effects. These risks have been associated with health problems such as immune deficiency, kidney diseases, cancer, and renal tubular dysfunction.

Biological Risks in Cereals

Biological risks in cereals come from microorganisms like bacteria, fungi, and yeasts. These organisms can harm cereal health and grain safety when conditions like temperature, moisture, and pH are propitious for their growth.

Fungi infection may occur before or after the harvesting period. In the first instance, fungi can act with humidity levels over 25%, while in the second case, it could be below 17%. Certainly, their presence depends on many different factors other than humidity, such as temperature, oxygen content, storage time, and grain condition. Aspergillus flavus and Aspergillus parasiticus are some of the most notorious fungi that produce toxins, aflatoxins which are previously mentioned in chemical risks.

Cereals are raw agricultural products, so they contain a microbial load. However, bacterial contamination is observed the least in this product category since cereal grains are dry, and bacteria thrive in specific temperatures and high moisture content conditions. Thus, when cereal grains have high moisture content, bacterial contamination emerges. It is worth mentioning that most of these contaminants can influence final products, such as bread. Bacillus cereus, Salmonella, Clostridium botulinum, and Escherichia coli are only some of the pathogens that affect cereals.

In a 2022 risk ranking conducted by FAO[3] aimed to support microbiological management for low-moisture food, cereals were examined alongside other low-moisture foods like dried fruits and vegetables, nuts and nut products, seeds, confectionery, and snacks. The results showed that cereal grains scored the highest in three out of four of the evaluation criteria (international trade, the burden of disease, vulnerabilities due to food consumption, and vulnerabilities due to food production). FAO emphasized the need to control microbiological hazards in cereals and other low-moisture foods to protect consumer health.

Physical Risks in Cereals

An extraneous plant pieceweedmetalpest, or plastic part are some examples of physical risks in foodstuffs. Ultimately, physical risks account for foreign bodies that somehow end up in food and are not intended for consumption. Their consequences on human and animal health are diverse, from poisoning to causing injuries.

Physical risks may occur when any foreign matter enters the product during harvesting, processing, storing, or transporting. Insects, rodents, and mites are significant potential and frequent dangers for cereal grains. Depending on the pest, they tend to both pierce the grain or nourish from its fragments or by potential fungi presence.

To minimize the potential food safety risks associated with cereal grains, farmers need to take measures towards implementing good agricultural practices and monitoring the contaminants. This includes making sure that they have handled, processed, transported, and stored their crops properly. For instance, facilities need to be clean and well-maintained according to regulated standards in a dry, cool storage place to avoid mold growth. By taking these precautions, farmers can ensure that cereal grains continue to be a safe, available, and nutritious food source for humans and animals around the globe.


[1]  https://www.atlasbig.com/en-ie/countries-by-total-cereal-production 

[2] https://data.worldbank.org/indicator/AG.PRD.CREL.MT?end=2021&start=2017

[3]  https://www.fao.org/3/cc0763en/cc0763en.pdf

Oluwadara Alegbeleye, Olumide Adedokun Odeyemi, Mariyana Strateva, Deyan Stratev, Microbial spoilage of vegetables, fruits and cereals, Applied Food Research, Volume 2, Issue 1, 2022, 100122, ISSN 2772-5022, https://doi.org/10.1016/j.afres.2022.100122.


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