Oxygen-sensitive sensor can challenge MAP

14 Nov 2011

An oxygen-sensitive colour change sensor used to determine the shelf-life of packaged food could challenge industry food quality and safety practices, says its UK-based inventor.

The development, a sensor which turns blue where excess oxygen is present, indicates when food such as meat may have been compromised and made unsafe for consumption.

The sensor, which was developed by Professor Andrew Mills and other researchers at Queen’s University, Belfast, is made of titanium nanoparticles coated with methylene blue dye and sacrificial electron donor DL-threitol.

Once activated for use using photobleaching with UVA radiation, the sensor will turn blue when in the presence of oxygen.

Challenge MAP process

Professor Andrew Mills said that the development has the potential to challenge packaging techniques such as modified atmosphere packaging (MAP).

This technique, used commonly with products such as meat, uses inert gases such as nitrogen and carbon dioxide, which are flushed through the package to reduce the oxygen concentration.

"With the current methods, once it leaves the factory it is very difficult to know the quality of the packaged food. With the sensor, it will make sure that the product is safe to consume once it gets to the consumer,” said Mills.

“With the MAP process, quality assurance takes place at the packaging stage by checking 300 or 400 packages. If one is found to be tampered with or damaged then they will scrap the last few hundred, which is wasteful and shows a lack of quality assurance.”

“This technique will ensure the quality and safety of the packaged food, allowing everyone from the farm to the fork to check their food is properly packaged and safe to eat.”

Commercialise technique

The presence of oxygen in food packaging promotes microbial growth and protein decomposition – leading to food spoilage.

Techniques for establishing the presence of oxygen in packaged foods are already commonplace, but many can be expensive and can require specialist equipment for analysis and trained operators.

According to Mills, the new sensor is cheap enough for commercial use – which they hope will help to prevent food waste and increase food safety and quality.

The professor said: “here are plans for commercialisation of the technique. It is still in the early stages of development, but there is already strong interest in developing the technology.”

“Around 60bn food items are packaged using MAP, so it is a massive industry to tap into.”

“We have previously developed other smart pigments, where were able to detect gases related to food decay in packaged foods.”

“That has already been commercialised, and this technology will follow the same stream,” added Mills.

Source: Queen’s University Belfast