in case of excess oxygen, the sensor turns blue, showing to the customer that the food is not fit for eating. oxygen fastens food spoiling procedures such as protein decomposition and microbial growth. this is the reason why most of the food packaging is done with the help of using modified atmosphere packaging. in the modified atmosphere, gases like nitrogen and carbon dioxide are flushed through the package to reduce the oxygen concentration. already, there are techniques to check oxygen in food packages. however, they can be costly and few also require expert analytical equipment and qualified operators. the easytouse technique of the colour change sensor, which is developed by andrew mills and his coworkers at queen&39s university, which is located in belfast, is that the integrity of package can be seen in situ by the customers and is quite affordable for commercial use. the sensor is made up of titanium nano particles and layered with methylene blue dye as well as sacrificial electron donor dlthreitol, is triggered for use by photo bleaching along with uva radiation. after the stage of photo bleaching, the sensor will only turn up in blue colour in the existence of oxygen this procedure can be recycled. however, it can be done only by repeating the stage of photo activation. by integrating this technology into food packaging processes, huge amount of food waste could be averted, claims mills. mills further said that, alone in the uk, people throw away more than £10 billion of food waste per year which can be averted. indicators integrated in food packaging can help to minimize this by simply informing the customer the consumer, retailer or wholesaler as to the state of the food. mills says that many of us discard food just because the uncertainty of the freshness. so, an indicator of &39consume within&39 would help to resolve this issue. joe kerry is an expert in the department of innovative food packaging at university college cork, which is located in ireland. joe also agrees that this is a quite interesting area of research. joe says that they have moved away from oxygen elimination materials as people had all types of issues regarding the active packaging sachet, mostly because people were really consuming them. joe says that the technology offered here is really exceptional and is a different type of system. the best thing about this technology, according to joe, is that it is nonreversible an accumulated colour change eventually. there are many pros and cons to using a technology that is either reversible or nonreversible. source of information httpwww.rsc.orgchemistryworldnews2011november11111102.asp
