As we mentioned in the post dealing with the general advantages of silo bags vs. steel silos, the first have proven to be especially efficient for food storage or grain storage, but as we will see next, they also create an environment protected from insects and diseases. When closing the bags, the oxygen level decreases and carbon dioxide increases. As a result, diseases caused by fungi and insects are almost completely eliminated, reducing the need to use chemicals on the food storage.
It is worth mentioning that, especially in the case of corn and grain silage, the mycotoxins that are mostly present are the Fusarium fungi that produce deoxynivalenol (DON) and fumonisins. These are field mycotoxins that must be controlled before storing the food, just like insect control upon harvest. For these reasons, thorough field control is crucial for the quality of the food stored. We will discuss the subject in this article and get into more details in following posts.
Those who prefer steel silos claim that grains and corn are much better preserved in these structures and that in fact, they can better avoid the fermentation problems that can originate in plastic bags used for silage bags.
However, to demonstrate the efficiency of silage bags in maintaining the quality of the food product stored, we would like to mention several scientific studies carried out that compare different methods of food storage or grain storage and contrast them with tests to measure the nutritional value and the presence of diseases. In this post, we will make a brief summary of the results; however, for further information each of the publications can be consulted.
Studies regarding silage bags and the quality of the product or grain stored
First, let’s discuss the study “Biological utilization of insect infested wheat stored in different storage structures”, (Samuels and Modgil, 1999). This publication deals with an experiment performed during six months with wheat stored in jute bags, metal containers and polyethylene bags (silage grain bags).
The different types of storage were filled with the same wheat, and mice were fed with this wheat after six months. The food from the jute bags exhibited much higher levels of infections compared to what was stored in polyethylene bags and metal containers and, consequently, the animals registered lower nutritional values.
On the other hand, the study “Evaluation of quality attributes and the incidence of Fusarium sp. and Aspergillus sp. in different types of maize storage” (Di Domenico, Hasimoto, Busso, Coelho, 2015) also demonstrates the effectiveness of silage grain bags to maintain, in this case, the quality of corn.
The objective of this study was to evaluate the quality of corn grains and cobs stored in conventional polypropylene bags, vertical steel silos and polythene hermetic bags for 12 months. Two varieties of corn were used for the study of the parameters of “moisture content, ash, proteins and lipids, percentage of healthy grains and the incidence of Fusarium and Aspergillus species”.
These parameters were evaluated during the 12 months of the experiment in the different methods used for storage. In all cases, “it was demonstrated that polyethylene hermetic bags (silage grain bags) are a good option to maintain corn grain quality.”
In another study, “Dynamics of fungi and related mycotoxins during cereal storage in silo bags”, (Gregori, Meirggi, Pietri, Formenti, Baccarini, Battilani, 2013), it was also shown that silage bags are a safe storage method for cereals.
In this case, the objective was to evaluate how fungi and related mycotoxins behaved in the storage of cereals (corn and durum wheat) during a period of two years. To measure results, data was collected on temperature, oxygen and carbon dioxide inside the silos.
During the different evaluations over the two years, it was determined that the temperature inside the silage bag “followed the trend of the outside temperature, with a more limited variation. A decrease of O2 was observed from 16.4% to 2.0% for the corn and from 15.7% to 15.1% for the wheat; the decrease was balanced by the increase in CO2. There were minor variations in the activity of grain water and CFU (colony forming units) and the mycotoxin content did not change significantly during the storage period; the results were consistent in the two years.”
The importance of appropriate conditions to store food
Finally, the study “An inside look at the silo-bag system”, (Bartosik, 2012), evaluated the method of silage bags to store food and the quality of this storage system.
In this case, the study highlights the importance of having the appropriate conditions to store food in the silage bags. “The general results indicate that the dry grain (equilibrium relative humidity below 67%) can be stored in a silage bag for more than six months without losing quality. If the moisture content of the grain increases, commercial quality could remain the same for a maximum of six months in winter to less than three months in summer. In all cases, maintaining the air-tightness of the bag is a key factor for successful storage.”
This shows that the silage bags are an effective storage method for disease control of fungi and insects, but on the other hand, a more economical system compared to steel silage, that are more flexible, and offer possibilities to harvest more efficiently among other benefits.