Portable nano and micro sensors developed for food safety

The development means food samples would no longer have to be sent to a laboratory for tests - a comparatively lengthy and costly procedure - but could be analysed for safety and quality at the farm, slaughter house, during transport, or in a processing or packaging plant, the project's researchers say.

Currently the detection of bacteria or pesticides in different foodstuffs is only possible by sending samples to a laboratory and waiting hours or days for the results. A portable device would not only accelerate the testing procedure, but would allow more tests to be carried out on more produce samples, increasing the overall safety of the food.

The Good Foods project aims to achieve full safety and quality assurance along the complete food chain stated Carles Cané, the coordinator of the project at the National Microelectronics Centre in Spain.

The project is developing tiny biomechanical and microelectronic sensors that can be used to screen for virtually any pathogen or toxin in any produce. The project partners are focusing their research on quality and safety analysis for dairy goods, fruit and wine.

The scientists are developing a device based on a fluorescent optical biosensor that measures the reaction of a probe coated with antibodies when it comes into contact with antibiotics present in milk or other dairy products.

Though the use of antibiotics as growth enhancers is prohibited in dairy cattle in Europe, farmers are permitted to use them in treating ailments affecting individual animals.

The antibiotics can enter the milk and could prove harmful to consumers by creating cumulative resistance to antibiotic treatments. The threat is particularly harmful of the contaminated milk ends up in baby food.

Currently producers check milk for antibiotic residues using a non-reusable litmus paper testing kit. An electronic device of the kind being developed by GoodFood would make the tests faster, cheaper and more accurate, the researchers stated in a press release yesterday.

Cost benefits and accuracy would also result if a microelectronic device is used to detect pathogens such as salmonella and listeria bacteria in milk, cheese and other dairy products, they stated.

The partners in the project are also developing a device using DNA biochips to detect pathogens - a technique that could also be applied to determine the presence of different kinds of harmful bacteria in meat or fish, or fungi affecting fruit.

They also plant to develop other sensors based on an immunodiagnostic microarray that can be used to identify pesticides on fruit and vegetables.

Sensors could be used to measure the quantity of oxygen and ethylene - a gas produced by fruit as it ripens - in fridges where unripe fruit is stored for months until it is ready to go on sale.

The faster in-house testing would give suppliers greater control over how well the produce is being maintained.

Sensors could also be used to measure environmental and climatic conditions at the farm. The additional information would give farmers more control over the quality of their crops, especially when the sensors are connected wirelessly to an analysis system.

Such sensors and other systems developed by the project are being tested this year at a vineyard near Florence in Italy. GoodFood sensors will be used to monitor grapes due to be harvested next September.

"Wine making is a precise art and a difference of a few days in when the grapes are picked can make a huge difference in the quality of the wine,"​ Cané stated.