Miller Magazine Issue: 115 July 2019

77 ARTICLE MILLER / JULY 2019 Low Oxygen: Different applica- tions for different commodities Despite the fact that there are data avail- able for the use of low oxygen in different types of facilities, this technique has be- come much more adaptable in the case of disinfestations of commodities. Low oxygen is a generic term, and its definition is much more complicated that the initial impression of this term indicates. Hence, low oxygen levels can be obtained by changing the pressure in a given area, which, indirectly, results in reduced percentages of the gases that occur in this area, including oxygen. At the same time, low oxygen can be also ob- tained by the increase of the percentage of other gases, which again results in reduced oxygen percentages in the target area. This last technique can be obtained with the use of different gases, such as carbon dioxide or nitrogen, with nitrogen being the most popular during the last couple of decades. The idea behind such an application is really simple, the in- crease of nitrogen causes a concomitant decrease of the other gases, especially oxygen, which is vital for the survival of different insects and various types of fungi and bacteria. Low oxygen can be used in packaged goods, as long as the packages are gas-tight, and there is no interaction with the external environment. This is usu- ally achieved through flushing nitrogen or other gases inside the package before sealing. Moreover, atmos- pheric nitrogen can be taken from the air and applied in sealed chambers that contain different types of du- rable commodities, ranging from grains to dried fruit. In this effort, sensors (i.e. oxygen detectors) are es- sential to indicate the success of the application and the distribution of the gas throughout the target area. Finally, nitrogen can be also utilized with success in bulked grains, a scenario that is qualitatively different than the above, and prob- ably the most demanding. Nitrogen in silos: A dynamic procedure The application of nitro- gen in silos has nothing to do with the application of nitrogen in chambers, for different obvious rea- sons. First, a silo needs to be sealed, and even if it is sealed, this sealing is defi- nitely inferior that that in chambers. In this context, any application of low ox- ygen in silo needs a con- siderable amount of time to Controlled atmosphere mobile unit (blue container) treating metal silos with nitro- gen (low oxygen method) in Greece. Silo treatment with nitrogen (low oxygen method)