DairyGuard fights against milk powder adulteration

DairyGuard Milk Powder Analyzer uses near-infrared (NIR) spectroscopy for confirming certificates of analysis (COAs) for protein, moisture and fat.    

The Frontier NIR platform tackles the issue of low-cost ingredients that may have been economically adulterated.

Near Infrared Reflectance Accessory (NIRA) II features a cleanable surface and rotating sample holder.

The machine applies algorithms to screen for known and unknown economic adulterants in milk powder and performs measurements for protein, moisture and fat monitoring.

Adulteration detection​

Guido Lohkamp-Schmitz, line leader central material characterization, said it can detect adulterants, even those that are unknown, and specifies and quantifies them.

He told FoodQualityNews.com at Analytica 2014 in Munich that the tool for unknown adulterants is on the way to be patented.

“The key background is the classical NIR measurement, you work with the first input and then it checks the differentiation of the standard material to the material out of the model you set up, which is set-up fully automated.​

“​When the sample checks out, it falls out of the model. It then checks what must be added to obtain a reasonable result, then it goes through and checks the different adulterants.”​

“If it doesn’t find any of the classic adulterants that have been added into the model, it will then look at the worst spectra which is great enough in intensity. Then it will show you that your sample is adulterated.  Because it is so sensitive, you can set a limit and it will give you a linear relationship of how much adulterant you have in your sample.”​

Software basis​

The Spectrum Touch software tells the user whether the milk powder’s protein, fat and moisture levels are at an acceptable level with a green (pass) and red (fail) system.

Through non-targeted testing it alerts the user to known or unknown adulterants in the milk powder.

The machine has a dual-range option to do NIR and mid-infrared analyses (MIR) which makes it easier to switch between transmission, reflectance and transflectance modes.

Standard assays involve measuring the total nitrogen concentration and relying on a constant calibration factor to get the protein content – so by adding nitrogen-rich compounds to protein-rich foods, a higher protein content reading could be generated leading to a higher price.  

How it works​

It can accommodate various size petri dishes for easy measurement in lab environments.

“The quantification level we can get down to is 0.1%, but normally adulterants are at much higher percentages or else it wouldn’t make sense financially to do in the first place," said Lohkamp-Schmitz.

“The software is designed for any other model, it doesn’t matter if you measure honey, or even tea. Any specific, most likely critical material, which may be easily adulterated can be easily extended and set up.​

“You don’t need to be an NIR expert…but for developing or maintaining the method, like adding new or emerging adulterants, you should have someone with a bit more spectroscopy knowledge as a resource.”​

He said the next step for a more precise analysis would be to go to a LC/MS-MS or TOF system.

Lohkamp-Schmitz said milk powder would be put onto a dish and then the automatic spinner, which can be removed at any point.

It spins the sample to get a measurement and while it is being measured the user is taken through a logic task list which gives advice before giving an automated result analysis.