Processed Foods
Most processed foods have a multitude of different ingredients and undergo a range of processes before being packaged. Inconsistency or variation in any one of these processes can have an immediate and detrimental effect on product quality and customer experience.
If “allergen free” claims are being made, there are simple “allergen dip tests” that can be completed onsite to ensure the product is safe and meets its labelling. For dietary claims such as protein, fat, moisture or starch there is a simple test that can verify levels of both ingredients and final product in only 6 seconds. Vitamin content however will require laboratory testing from a certified laboratory.
For a multi-constituent product (e.g. chocolate chip cookies) it is important to ensure that the testing sample has the same proportion of constituents as the finished product. However, it is possible for the different ingredients to have different moisture contents but equivalent water activities, because this, water activity is considered a better quality control indicator than moisture content.
“Processed food” is a very wide product category, it could include cooked, cured and processed meats, ready meals and convenience food products. Dansensor, specialists in instruments that verify the gas flushing process have a very good “MAP Mix Guide” that can be referred to. A good starting point is 30% CO2 / 70% N2 but it is advisable to identify the best gas mix for your product through a MAP LAB Trial.
For shelf life stability and prevention of pathogen growth, Ministry of Primary Industries (MPI) recommend a water activity of below 0.85. It is also extremely important to prevent moisture migration by ensuring that the different constituents are at an equilibrium water activity, normally by the use of humectants.
With the complexity of most processed foods, the conscientious Quality Assurance engineer may wish to know anything from the fat content, through to moisture, salt, protein, sugar and more. The common problem is that these tests can take time – anywhere from a few minutes to half a day or more. Meanwhile, production doesn’t stop. There is a final product that needs to be (or has been) packaged but cannot be released from the Quality Control process.
This is where analysis with NIR or “Near Infra-Red” Spectroscopy can be invaluable. Working with the Perkin Elmer DA7250 a comprehensive compositional analysis can be completed in only 6 seconds. Adding to the convenience, there is minimal sample preparation and no need for cleaning between samples as it is a top scanning NIR with a very large surface area for sampling. At the completion of the scan the user simply dumps the contents of the sample tray and then scoops up the next sample.
If continuous, real-time monitoring, with PLC output for real time recipe adjustment is preferred, this can be achieved with either the over-belt Perkin Elmer DA7350 or the in-pipe Perkin Elmer DA7440. Both instruments deliver the capability to monitor and adjust inputs during processing – virtually eliminating the need for cumbersome, expensive, and inefficient reworks.
Meter Food, the pioneers in Dew Point Water Activity Meters have a comprehensive and simple explanation of the difference between moisture content and water activity that can be viewed in the Meter Food knowledge base. In very simple terms – moisture content is the amount of water present in the product, while water activity is the water available for chemical / microbial reactions.
When producing processed foods this difference is significant. Ingredients that are humectants (water activity reducing ingredient), such as sugar, salt or glycerine reduce the water activity without impacting the moisture content. For processed foods, the water activity will normally need to be below 0.85 for microbial growth safety. To ensure food safety and protect against unwelcome product recalls, as well as to maintain a consistent product the well-informed quality control specialist will use water activity as a Critical Control Point (CCP) – testing every batch for safety and consistency.
Working with Meter Food, Mätt Solutions offer a comprehensive range of Water Activity measuring solutions that cater to the full spectrum of users. This starts with the Aqualab PawKit, a fast and robust solution for at line measurements or verification. The PawKit was designed for the auditor, inspector or verification at the factory floor.
Where a greater degree of accuracy or faster measurement is required, Meter offers the Aqualab 3 or AQ3 – which delivers aw readings in only 60 seconds and can be fully integrated into a process control system. For lab grade accuracy or product development there is the Aqualab 4TE and Aqualab TDL (Tunable Diode Laser). This entire range offers aw to an accuracy of 3 decimal places, and in the case of the Aqualab TDL can manage volatiles, oils and even petroleum products – a traditional stumbling block of Water Activity Meters.
Modified Atmosphere Packaging (MAP)/ gas flushing is often used to extend the shelf-life of products without the addition of preservatives. For this to be successful, the MAP gas (O2, CO2, N2 etc) must be maintained at the right level from initial packaging through to consumption by the end user. The package must not have leaks and the packaging material must have the right oxygen and water vapour permeability properties.
Mätt Solutions, as a specialist in MAP, have the right solutions to test and verify not only that the gas mix going into the package is correct, but that this mix is maintained throughout the shelf-life of the product. The AMETEK MOCON range of gas mixers like the MapMix Provectus, head space analysers like the CheckMate 3 and leak detection instruments like the LeakPointer3 allow complete control and monitoring of the gas composition needed for processed foods.
The Dansensor CheckPoint 3 (portable at line) and Dansensor Checkmate 3 (desktop) O2 / CO2 analysers can be paired with non-destructive (packages can be sold after testing) leak detection in the form of the Dansensor LeakPointer 3 to provide the quality control needed to confidently release products to market. Another option for leak detection is a Haug Waterbath or Dansensor LeakPointer H2O. The big advantage of a waterbath is that the site of the leak can be seen - helping in the diagnosis and trouble-shooting of any issues in the packing process. The negative with the waterbath option if that it is considered a destructive method (packages must be disposed of after testing)
Mätt Solutions offer shelf-life testing services that look at the product's "complete picture", considering all its aspects to determine when and what ends a processed food product’s shelf-life. Packaging provides protection from extremes in light, temperature, humidity and oxygen all of which will reduce shelf-life if not controlled. To perform an accurate shelf-life test, it is imperative to expose the product to different conditions to know when and why it fails.
Mätt Solutions have a wide selection of chambers and simulation set-ups to test these extremes and help determine the shelf-life and durability of dry food products by offering both accelerated and real time shelf-life studies as applicable. At the end of the trial, a comprehensive report is provided that states the actual shelf-life of the product, outlines reasons for failure and in most cases recommends ways to improve. This report tends to be a requirement by most supermarket chains and is well received by auditors and MPI (Ministry of Primary Industries)