Modified Atmosphere Packaging Quality Control
When packaging in modified atmosphere it is crucial to ensure that the gas mixture is correct and the package is not leaking. For most products it is also important to set limits for the maximum and minimum residual oxygen level in the packages.
According to EU and US regulations all manufacturers producing products with a reduced oxygen content or protective atmosphere have to set up critical control points regarding both the gas content and the seal integrity. As a minimum you will need to follow basic Hazard Analysis and Critical Control Point (HACCP) rules.
Basic HACCP – Analysis
- What can go wrong? (e.g. wrong gas mix, incorrect residual oxygen level, leaking package)
- What can you do to prevent this from happening?
- Control (objective proof)
Basic HACCP - Critical Control Points (CCP)
- Establish a procedure to ensure that the packaging process is always under control
If something goes wrong – how can you get the process back in control?
- What will you do with the incorrectly packaged products?
- How do you stop the process?
- What will you do to prevent this from happening again?
Basic quality control for modified atmosphere packaging (MAP) products
The simplest form of quality control for MAP products includes taking out samples on a frequent basis, e.g. taking out samples every 15 or 30 minutes according to production speed. The sealing of the packages should then be inspected for leaks – preferably using a non destructive test method. Afterwards the gas mix and residual oxygen level should be checked using a headspace analyser.
The result of the above tests should as a minimum be recorded on paper for traceability purposes, however, it is far more convenient and efficient to let the headspace analyser collect the data and store it in a central database or on a PC.
When setting up the random quality control it is important to notice that even though you take 10 samples per hour the statistical significance could be as low as 0.15%. The table below gives an idea of the relation between packaging speed and samples taken.
| Packaging Speed (number of packages per minute) | ||||||
| Tests per hour | 30 | 50 | 70 | 90 | 110 | |
| 5 | 0.28% | 0.17% | 0.12% | 0.09% | 0.08% | |
| 10 | 0.56% | 0.33% | 0.24% | 0.19% | 0.15% | |
| 15 | 0.83% | 0.50% | 0.36% | 0.28% | 0.23% | |
| 20 | 1.11% | 0.67% | 0.48% | 0.37% | 0.30% | |
Quality control or quality assurance?
An important consideration to make when working with MAP packaging is to choose between a manual quality control system (as described above) and an automated quality assurance method. With quality assurance an on-line gas analyser is mounted on the packaging machine, thus continuously monitoring the gas mixture and residual oxygen in a non-destructive way. The greater the speed of the packaging machine the more important it is to consider quality assurance, as a QA system will reduce labour and waste costs.
Imagine that you take 10 samples per hour on your packaging machine and that the machine is in operation 16 hours a day for 250 days a year - this would result in a total of 40,000 tested packages a year. Since manual testing is destructive the consequence would be a substantial amount of waste and many hours spent on repacking.
