Dairy plants in New Zealand are operated to extremely stringent standards, particularly when exporting infant formula/milk powder. A wide range of expertise is needed from the Quality Assurance (QA)/Quality Control (QC) team, along with support from knowledgeable engineers. Such quality control can start by ensuring that products meet the nutritional values intended, water activity required and packaged in a way that the gas composition is correct and that there are no leaks. Dairy has a wide variety of testing needed to control quality and process.


What is the fastest most accurate way to perform compositional analysis on raw milk?

Dairy liquids need to be analysed for components such as fat, protein, lactose, totals solids, solids non-fat, added water, true protein, casein, NPN-CU, free fatty acids, citric acid, density and pH. 
Analysis of these components is best performed with a Fourier-Transform Infrared Spectroscopy instrument (FT-IR). Mätt Solutions supply both at-line and off-line FT-IR analysers. The Lactoscope FTIR Advanced from Perkin Elmer provides accurate analysis of fat, protein, carbohydrates, solids, solids non-Fat, pH, free fatty acids, citric acids, NPN/calculated urea, casein, density, freezing point depression, NPN and true protein. The LactoScope’s easy operation and quick set-up gives the quality manager a perfect tool for milk and cream standardization, and the analysis of more complex dairy products such as yoghurts, cheese milk and ice cream.
Dairy Powders need to be analysed for moisture, protein, fat, ash, lactose, alkalinity, oleic acid, monounsaturated FA, poly unsaturated FA, saturated FA, and total unsaturated FA.
Dry powders are analysed using NIR (Near Infra-Red) that performs multicomponent analysis off-line in 6 seconds and on-line in real-time. The online solutions also come with cameras able to perform spec counting or burnt particle measurement. Mätt Solutions supplies both on-line and off-line NIR analysers.

How can I measure the physical/rheological properties of dairy samples?

The RVA (Rapid Visco Analyser) is the best solution for determining how dairy products perform under varying conditions. The RVA enables the measurement of ingredient performance; simulates process conditions and creates miniature batches of product (10-25 ml)
Dairy - Process cheese manufacture and melting profile, effect of drying temperature on milk protein powders, rennet caseinate rehydration, dairy beverages, custard, age thickening of sweetened condensed milk and "Miniature Pilot Plant" small scale manufacture of yogurt, ice cream mix and dairy desserts.


What Does Bulk Density tell me?

Bulk density is the weight of a volume unit of powder and is usually expressed in g/cm3. For the powder manufacturer, whether air drying, spray drying or freeze drying, a measure of the bulk density is useful on two key fronts – it will provide information regarding how much a powder can be expected to “settle” in the package during shipping, how much weight a package can hold in terms of volume/ fill height, which also has as direct impact on customer perceptions.  We are all familiar with filling up the flour container at home, we fill it, shake a little and then add some more to the container to top it up. This is what the Engelsmann StavII jolting bulk density meter does. It “taps” a cylinder and you get a measure of how much the powder can settle in terms of volume

What is MAP in dairy packaging, MAP and permeability analysis?

Modified Atmosphere Packaging (MAP) in dairy involves removing atmospheric air from the powder and replacing it with a low oxygen mixture of Nitrogen (N2) and Carbon Dioxide (CO2) or for skim milk-based products this is usually pure Nitrogen (N2). This extends the shelf-life of the product and can help to prevent unpleasant odours or taste that come from lipid oxidation. 
Matt Solutions has a range of solutions, both off-line gas analysers and real time on-line gas analysers, gas mixers and both destructive leak testers and non-destructive leak detectors.
The Ametek Mocon - Dansensor range of head space (otherwise referred to as Residual Oxygen or R.O) gas analysers provide a robust solution for Oxygen (O2), Carbon Dioxide (CO2) and Nitrogen (N2) displayed as a balance. Mätt Solutions have developed a variant of the CheckMate 3, the popular desktop RO gas analyser that is able to sample a can packed under vacuum conditions.  This has traditionally been a stumbling block, especially in canning, as few head space gas analysers on the market are able to draw an effective sample under vacuum conditions. Key to also maintaining product quality is can/tin integrity.  Along with leak detection solutions, there are seam inspection devices that the well-prepared professional will use during each production run.  The reason for this is simple – when you’re producing a high value, high quality product you don’t want to face costly repacks or product disposal due to a poorly sealed seam or poorly made can.  In this regard it’s recommended that all can quality parameters are checked.  For this, Canneed offers a suite of devices that can monitor all can integrity parameters, from the Seam thickness with a countersink gauge to “hook” size with the Seam Sight.  This will rely on the precise and clean cut of the seam as produced by the specialist Canneed Seam Saw.  
Working as a team, these devices will conduct a comprehensive seam tear down analysis. 

How do I tell if I have leaking packaging?

Leak Detection must not be forgotten in all of this.  Products that are exported, particularly to hotter/humid regions are extremely susceptible to failure from a poor or weak seal. With this in mind, a quality leak detection system can be an invaluable insurance policy.  At it’s simplest level – leak detection starts with the tried and true waterbath – immersion in water followed by drawing a vacuum to create a pressure differential between the inside and outside of the package. We then look for leaks – both the Haug PackVac and Dansensor LeakPointer H2O excel in this area, with chambers as large as 85cmx65cmx60cm they offer a robust and easy to use solution. If non-destructive leak testing with truly objective results is preferred, there is also Bestech, which works based on pressure decay and the Dansensor LeakPointers which detect the presence of CO2. 


Is there a fast way of verifying cleanliness or checking for allergens?

It is important to ensure that cleaning is carried out correctly and that there is no chance of cross contamination or of microbial growth.  This is where a good sampling regime with a product such as Eurofins PureBlu Swab Sampler and Eurofins Ezy-Reach Sponge sampler come into play, both of which offer a 72-hour viability post sampling for testing of microbial growth.  Complementing these products is a wide range of allergen detection kits in ELISA (for quantitative allergen measurement) or Lateral Flow (for at line qualitative detection) formats. 


How do I prevent caking and clumping?

A major hurdle with exports of dairy powders has always been caking and clumping.  To measure and subsequently avoid this, water activity (aW) is a key factor.  Working with Meter Food (formerly Decagon - Aqualab), Mätt Solutions offers a comprehensive suite of water activity meters that are suitable for all dairy applications.  This includes the PawKit, an at line meter suitable for inspectors or spot inspections, the exciting new Aqualab 3 (AQ3) – offering water activity and moisture analysis in only 1 minute, the highly accurate Aqualab 4TE, or if the sample has volatiles the Aqualab TDL 2 (Tunable Diode Laser) that can deliver accurate aW readings – even of petroleum-based products and oils. 

Is there a better, more flexible way of environmental monitoring than hardwiring the entire plant?

With dairy plants often being “spread out” and the requirements for continuous chain of custody/monitoring of conditions needed, a robust datalogging solution is vital.  For this, the preferred modern solution is wireless data-loggers paired with a cloud-based data management system.  The Monnit suite of loggers, which offer both a battery life in excess of 10 years and a 300m wireless range, are perfect for use in all dairy manufacturing environments. The particular strength of a wireless solution is that loggers can be sited quickly and easily where they are needed and then moved, whether with product or as the needs of the business evolve.  
The Monnit software enables monitoring of all loggers on any web-enabled device.  Making this even easier is the ability to assign custom names to each logger (eg: drying room 1 or infant formula storage).  Access to specific loggers (or groups of loggers) can be assigned on a functional team basis, and is easily changed or edited. ALL information is then stored in a secure, web-enabled format, making data collection for audits a simple process – and this is all 21 CFR part 11 compliant. 

How do I check the shelf life of my products when there are variable cold chain conditions?

Mätt Solutions offers shelf-life testing services that look at the product's "complete picture", considering all its aspects to determine when and what ends the shelf-life of dairy products. Microbial growth, pathogens, oxidation and sensory aspects like colour, odour and texture are all considered. 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.  For shelf life analysis on refrigerated products this can include abuse trials, such as the trip home from the supermarket. Mätt Solutions has a wide selection of chambers and simulation set-ups to test these extremes and help determine the shelf-life and durability of dairy products. 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) 

How much protein is in raw milk?

There will be approximately 3.6 grams of protein per 100ml of raw milk. The protein content of raw milk can be determined with a Perkin Elmer Indiscope or a Perkin Elmer Lactoscope.  

How much fat is in raw milk?

Raw milk will contain about 3.6 grams of fat per 100 ml. 
The fan content of raw milk can be determined with a PerkinElmer Indiscope or a PerkinElmer Lactoscope.  

How much calcium is in raw milk?

There are approximately 120 milligrams of calcium in 100 ml of good quality raw milk. 

How much moisture is in milk powder?

A milk powder will typically have around 5% moisture, however a far better quality guide will be the water activity of the powder.  Particularly in cases where the milk powder has been fortified with additional nutrients.  By measuring water activity, in conjunction with an isotherm, quality control parameters can be set to prevent caking or clumping – this is especially important when exporting milk powders as water activity will change with temperature. 

What is the water activity of milk powder?

In general, dried or de-hydrated products such as milk powders will have a water activity of below 0.60 aW.  In a product that is sold by weight, the more moisture that can be left in the product, the higher the yield will be. Many manufacturers will use a Moisture Sorption Isotherm to set critical control parameters, drying to a level that maintains quality (preventing caking and clumping) while maximising the moisture content and thus reducing drying costs and maximising yields. 

What modified atmosphere packaging (MAP) mixture should be used for milk powder?

Whole fat and skim milk powders require different gas flushing mixtures as fat will absorb CO2.  For skim milk powder, a MAP gas of 100% N2 is suggested, while for a whole milk powder, a 30% CO2/70% N2 may be preferred. 

I have been asked for “altitude trials” of my milk powder cans, what does this mean?

During airfreight, the shipment will be subjected to low pressure in the aircraft hold due to altitude. Altitude trials subject a can/package to low pressure to ensure that the top will not bulge/ “pop” and turn convex, making it unattractive to consumers. 

Why are some milk powder cans packed under a vacuum?

During airfreight, packages like cans may be subjected to lower-than-normal pressures in the aircraft hold.  This can cause the top of the can to “pop” or become convex. To counteract this “altitude effect”, cans may be packed at a slight vacuum.  In addition, a whole milk powder will absorb the CO2 gas that is used to extend shelf life – this can cause a vacuum to form in the can which is desirable for shelf life and visual customer assessment. When testing the MAP mix/gas content in a can (for QA/QC purposes) where a vacuum has formed it is extremely important to ensure that the pump of the RO analyser is powerful enough to overcome the vacuum and that an effective sample is being drawn from the can.    

My milk powder is free flowing when packed, but international consumers are complaining about caking/ clumping/lumps, what is causing this?

Water Activity (aW) increases with temperature (at a constant/same moisture content).  As many exported products are subjected to higher ambient temperatures than we experience here in New Zealand (in market or during shipping), they will be closer to their phase transition points when sold on international supermarket shelves, causing the (unexpected) onset of caking and clumping. 
When testing milk powder for quality assurance purposes, it is very important to use a Water Activity device with temperature control for consistent results. 

Applicable Instruments