Cereals are covered in bacteria, mold, yeast, and other microorganisms. As long as a cereal plant is alive, its constantly rejuvenated cell walls maintain an effective barrier against these microorganisms. These cell walls stop rejuvenating when cereal grains have been harvested. This leaves cereals vulnerable to decomposition.

Decomposition accelerates if the moisture content in grains is more than 14 percent and surrounding temperature is more than 15 degree Celsius. Bacteria and other microorganisms thrive the best under these conditions. They chemically react with cereal content and atmospheric oxygen to generate heat, water, and carbon dioxide. These chemical reactions further increase temperature in the interstices - sometimes to as much as 45 degrees Celsius, along with the water content in grains. This results in even faster degradation.

Some studies have discovered that an initial grain water content of 23 per cent and a temperature of 18 degrees Celsius can render cereals unfit for consumption in as little as a week.

Currently stores are using several methods for cereal preservation. One of the methods is to dry cereals to reduce moisture content to less than 14 per cent to inhibit microorganism growth. Another method includes storing grains at a temperature of less than 10 degree Celsius. Storing cereals in an atmosphere of carbon dioxide in silos is yet a third method. A fourth method is to treat cereals with organic acids, caustic soda, urea, or other chemicals. Chemical preservation is another method. It is cost-effective, although we’re not sure if customers are happy with chemical treatment of cereals.

A fifth method that has been rising in popularity is placing cereals under anaerobic (absence of oxygen) conditions. It includes storing cereals in an atmosphere of nitrogen. Nitrogen is biologically inert. Microorganisms do not react with nitrogen to carry out destructive chemical reactions on cereals. This method can be used to store cereals for short and medium periods. According to a study carried out by J. Shejbal of the “Laboratori Ricerche di Base” in Italy in 1979, anaerobic preservation is less expensive than chemical preservation.

Another advantage of nitrogen preservation is its scalability. Small amounts of cereals can be stored in stand up bags, foil pouches, and other kinds of pouch bags through nitrogen filling. Even though stand up pouch bags are rarely used for storing cereals for a long period, it is theoretically possible to do.

To conclude, for someone looking for an alternative to chemical storage methods to preserve cereals, anaerobic preservation is a promising alternative.