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Non-Invasive Infrared (IR) Sensors for Food Quality Assessment (AFM 247 Br) - FT1539

There are many ways in which the safety and quality of foods are measured. However, there is still a need for simple and effective ways in which such measurements can be made on the production line, where the waste of produce can be minimised.

This work builds on the experience gained whilst working on a related ultrasonics-based program, AFM227. The techniques developed were applied to other forms of measurement. It was discovered that light at wavelengths just outside the visible spectrum, namely in the near infrared (or NIR) can have surprising “penetration” through opaque foodstuffs such as cheese, chocolate etc, even when low-power and inexpensive LEDs are used as the source. This very preliminary work indicated that the same or slightly modified advanced signal processing techniques, currently used for ultrasonic measurements, might also be used for food quality inspection. This would potentially lead to a low-cost robust inspection method and associated on-line instrumentation, provided the subsequent product handling requirements are met. Thus, the simple use of a NIR beam, sent through the sample, could lead to the detection of foreign bodies or give information on the foodstuff quality.

Two potential applications have been identified; faulty product or foreign body inspection and food quality assurance e.g. fruit ripening and bulk cheese inspection. If the NIR transmission and scattering signal can be linked to product microstructure, then there may also be possibilities for in-line inspection of emulsions and other processed products including spreads, sauces, ice cream and water ice products. Two food industry partners, KerryGold and Bakemark, have already expressed interest in the potential applications of Warwick’s NIR in-line inspection concept. Thus, it is intended to focus the Bridge LINK proposal on their needs, hence generating the necessary letters of support. Both are interested in faulty product and foreign body inspection. Bakemark wish to inspect on-line doughnuts for missing jam, and Kerry Gold are keen to check incoming bulk cheese for entrained foreign bodies, particularly plastic, and uneven ripening/voids etc.

Warwick have set up a spin-out Company for their research, G-Tronix Ltd, and discussions have focussed on how the NIR approach to food quality inspection could be turned into a viable commercial venture for the Company. The Bridge-LINK proposal seeks to explore the scope of applications in the food industry and identify the technical hurdles which need to be overcome in order to define a robust product development route. Depending on the findings, the work could result in either a fully industrially sponsored product development venture, or identify and define a full LINK follow-on project proposal to tackle the proof-of-principle issues raised which impede immediate commercial exploitation.


1. To investigate a new near infrared (NIR) system that is very simple and robust.
2. To investigate the feasibility of using the new NIR system for on-line food inspection.
3. To explore the relationship between signal intensity and properties of the foodstuff, to form a basis for useful interpretation of the data.
4. To develop a low-cost and reliable system for NIR image reconstruction using arrays.
5. To work with several industries to demonstrate the usefulness of the technique in terms of food quality assessment and foreign body detection.
6. To recommend future work, via one of three possible routes: a future Foodlink programme, direct exploitation by G-Tronix Ltd, or an EPSRC proposal.
Project Documents
• Executive Summary : Non Invasive Infrared (IR) Sensors for Food Quality Assessment   (30k)
Time-Scale and Cost
From: 2007

To: 2008

Cost: £89,808
Contractor / Funded Organisations
University - Warwick
Food and Drink              
Food Industry Sustainability Strategy              
Food manufacturing industry              
Food Quality              
Manufacturing Efficiency              
Fields of Study
Resource Efficient and Resilient Food Chain