The importance of food security and food quality is a concept that resonates worldwide, as adequate nutrition is essential for proper growth, development, and function in all stages of life. The UN’s Food and Agriculture Organization estimates that by the year 2050, the world’s population will be over 9 billion, and global food production will need to increase by 70%.  It is imperative that food and nutrition security is ensured and improved in order for a nation to advance to its full potential.

Fertilizers will play a critical role in producing the volume of food necessary to meet the needs of a growing global population. Additionally, fertilizers ensure the quality of food crops, providing the soil with micronutrients that help crops grow while also enhancing the nutritional value of the food upon harvest. Countries around the world are conducting biofortification studies in order to evaluate soil conditions and execute plans for producing high volumes of nutritionally dense food crops.

Zinc is one of the key micronutrients being evaluated in these studies as it plays a key role in the successful development of all living things. In humans, zinc is vital for the majority of biological cycles and the regulation of protein metabolism. Zinc is also necessary for brain development and immune system support, especially in young children.

In agriculture, adding zinc to fertilizers increases plant growth and water intake, improving crop yield and resulting in stronger, healthier crops. As biofortification studies continue, zinc fertilizers are becoming more widely used to improve food harvests and combat zinc deficiency in humans around the world.

Some fertilizers, however, may contain impurities – such as cadmium – at levels that could be inappropriate or counterproductive to human and crop nutrition. In order to help assure the quality of zinc fertilizers, IZA launched its Seal of Approval initiative with the objective of ensuring the quality and purity of zinc fertilizers.

In partnership with Australia’s Commonwealth Scientific and Industrial Research Organization (CISRO), IZA developed a set of fertilizer contaminant limit values in zinc fertilizers based on the best available science. Using this information, IZA incorporated these guidelines into a Seal of Approval initiative. Once a company providing zinc (e.g. zinc oxide) for use in the fertilizer meets the qualification guidelines successfully, a seal of approval can be issued. These guidelines include:

  • Submission of company product specifications for zinc and impurities;
  • Submission of a quarterly product analysis for review and comparison with the impurity limits; and
  • Third party random testing of company’s product for verification.

Brazil is the first country to adopt the Zinc Fertilizer Seal of Approval.  Nexa’s zinc oxide, in addition to complying with all Brazilian laws, has been certified to meet the Seal of Approval specifications as a quality source of zinc for use in fertilizers. IZA continues to work closely with its Brazilian members to ensure best practices and generate participation in its Seal of Approval initiative.

Brazil was a logical place to introduce the seal as its agricultural business sector is extremely strong and well-developed. The Ministry of Agriculture, Livestock and Supply (MAPA) manages Brazilian legislation within the agricultural sector. Brazil’s primary fertilizer decree (number 4954 from 14/Jan/2004), regulates the inspection on the production and commerce of fertilizers, correctives, biofertilizers, inoculants for agricultural purposes, and other dispositions.  Impurities are addressed by the Interministerial normative (IN SDA 27 from 05/June/06 – Altered by IN SDA 07 12/April/16) which regulates the maximum limits of impurities in fertilizers.  In the case of zinc (and other fertilizers providing only micronutrients), the maximum allowed limit is 10000 ppm for lead and 450 ppm for cadmium.

Regulations imposed by Brazilian authorities, in tandem with IZA’s Seal of Approval Initiative, will help ensure that zinc fertilizers continue to contribute to food security and crop nutrition in a safe and sustainable manner.

For more information on IZA’s Quality Seal Initiative, visit

Andrew Green
Andrew Green, Ph.D.
Executive Director, International Zinc Association
Director, Zinc Nutrient Initiative