Packaging products in a modified atmosphere is currently a mandatory condition for many food products, prolonging the duration and preserving the appearance and taste by preventing or slowing down the processes of digestion. Simply, in the packaging with a modified atmosphere are used the main components of gases, from which the atmosphere of the Earth is composed - nitrogen, oxygen and carbon dioxide.
By changing the mixture or ratio we get the necessary properties that provide the extended preservation of food products.
Food nitrogen in Europe has the supplement number E941, as it is classified as a food supplement when used in packages with a modified atmosphere. Many other legislative bodies around the world also adopt the European standard or have a very similar specification.
Food supplement E941 specification:
- Nitrogen ≥ 99%
- Oxide ≤ 1% in
- Water ≤ 0.05% (500ppmV)
*99% including other inert gases, such as noble gases (mainly argon)
The Houses:
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External gas ≤10 ppmV
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Methane and other carbon (in the form of metane) ≤100 ppmV
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Nitrogen oxide and nitrogen dioxide ≤ 10 ppmV
Acceptable Maximum Residual Oxygen Content (MROC)
The main pollutant that should be considered within the specification is oxygen ≤1%, but this applies to the gaseous nitrogen itself, whether it is produced at the production site or supplied by traditional methods such as high-pressure ballons or in liquid form. One of the important factors for gas generation is that the higher the permissible level of the Maximum Residual Oxygen (MZV) in the output stream N 2, the less compressed air is needed for gas production and, therefore, the lower total gas unit costs. As a rule, for the obtaining nitrogen from the gas generator at 10 ppm (MZ) in a rate of less than 0.5%.
Often the oxygen content in the finished package of the product is empty with a gas that is more than 1%, this is actually an acceptable level, indicated depending on the type of food, and the intended duration, storage conditions and possible empty processes.
Many food producers use the services of independent expert research facilities, such as Campden BRI, in the UK. On these facilities, the condition of packaging and storage can be assessed, as well as the microbial assessment that relates to a specific food product to establish the optimal characteristics of the modified atmosphere, including the maximum residual oxygen content in the finished packaging.
A specific range of products that have a long storage period in a modified atmosphere are dry powder-like products such as coffee, dairy mixers and spices. They are usually packed using the vertical filling and lock equipment (WW), equipped with a special nitrogen production system. Parker has many gaseous nitrogen generators that work around the world, which are used to pack dry powder-like food products in a modified atmosphere using the WWW machines.
Nitrogen Generation on the Site: a Safe, Cheap Alternative to Traditional Methods
Food manufacturers applying packaging in the Modified Atmosphere (UMA) quickly realize the advantages of nitrogen production on the site as a safe, comfortable, sustainable and cheap alternative to traditional delivery methods. Some may seem that the transition from purchased gas to own production can be quite difficult and often insist on the fact that the new source of gas must meet the specifications regarding the oxygen content, i.e. the nitrogen generator must issue gas of the same purity as the purchased.
MRI in purchased gas against nitrogen generator
Sometimes there is a situation when the food producer wants to move to the Gas Generator ParkerBut insist on purity of 99.999% (maximum residual oxygen content of 10 ppm), unless it can be proven that a gas with a slightly higher oxygen content will exactly the same results. Despite the fact that the acceptable oxygen level in the finished package is usually about 2%.
Parker appreciates this position and fully understands that for food producers a lot is placed on the map to do it right. However, taking into account the use of purchased gas with a purity of usually 10-20 ppm, will it succeed in achieving 2% of the MSP in the ready packaging when transitioning to the independent nitrogen production, let's say, 0,5% of the MSP?
In fact, this is not the case, and the reason for this is that it is practically impossible to throw out all the air from the packaging, as it is quickly and continuously produced in the packaging machine, so some oxygen content from the surrounding air is always left. Secondly, when the product comes into the packaging from the doser through the loading fortress, it extract the surrounding air, thus putting a little more oxygen into the packaging.
One of the ways to determine the most appropriate permissible oxygen remains can be the installation of a small nitrogen generator system for work in experimental mode. However, in most cases such a approach is not logical and physically existing.
Thematic research
Recently, Parker UK faced a dilemma when a high-quality coffee maker desperately wanted to move from expensive and problematic liquid nitrogen supply to a solution. NITROSource PSA on the site.
The manufacturer was fully aware of the huge savings that could be achieved by applying nitrogen with a purity of 0.5%, not 10 ppm, but wanted to get the absolute evidence that the change of purity would not threaten its reputation and product.
To overcome the problems associated with the installation of a full-scale test plant, the Parker unit, the UK, has developed a solution for introducing a small amount of compressed air of food quality, which is supplied to a high-quality nitrogen package in 10ppm. Thus, allowing to increase the IAS to any desired level. On the output of the device, a decalibrated oxygen analyzer was installed for constant control of the level O 2.
A series of tests were conducted on one packaging line, where The device was installed.The manufacturer’s quality control department was ready to provide testing control and sampling of ready packaging with the use of a stable gas analyzer.
The machine worked with standard 36 packs per minute, first only with a nitrogen supply of 10ppm, and then with two levels of increased oxygen content of 0.1% and 0.5%, which was achieved by adding a small amount of compressed air of food quality.
As seen from the result table, there was practically no difference between the gas purity with regard to the MSP in the packaging, and the target level of O 2 wasined significantly below the required limit of 2%.
The test was assessed by the coffee manufacturer and the nitrogen generator NITROSource PSA was installed to meet the needs of the entire factory.
It is interesting to note that on the day of the transition from the available material reservoirs of liquid nitrogen to the Parker generator, the staff of the plant and the quality control department were not informed about this. We are glad to inform that the system actually worked for 3 weeks without any discoveries before the interested parties were eventually informed!
Given the overall cost of ownership, including electricity, maintenance and capital expenses, the entire system is expected to be recovered within 2 years and will later cut the expenses to 75%.
