Sunday, July 11, 2010


Ensuring processing adequacy is critical for food industry, especially for those employing thermal processing which is intended to achieve commercial sterilization. Many ready to eat type of products are required to be kept in the ware houses of the manufacturers for sufficient time for live cells of organisms, if any, to grow and manifest in tell tale symptoms like bloating, followed by random inspection before releasing to the market. The new machine vision technology based on Infrared rays is claimed to remove under processed or under cooked products from the production line with reasonable reliability.

"The food-processing industry is one in which high-level analytics are used with IR cameras for automated machine-vision applications. A field in which IR excels is the inspection of cooked food items coming out of a continuous conveyor oven. The primary concern is that the food has been thoroughly cooked, which can be determined by the IR camera measuring the temperature. This can be done by defining measurement spots or areas corresponding to the locations of the burgers as they exit the oven. If the temperature of the burger is too low, the machine-vision programme logic not only provides an alarm, but also displays an image to the oven operator to show the specific burger that should be removed from the line. As in other applications, minimum, maximum and average temperatures can be collected for specific burgers or the field of view as a whole. This data can then be used for trending and summary of product characteristics (SPC) purposes. In an example involving chicken fillets, temperature is again used to check for thorough cooking. The pieces come out of the oven and drop onto another conveyor in more or less random locations. The operator can use the thermographic image to locate undercooked items and then remove them from the conveyor. In the production of frozen entrees, IR machine vision can use pattern-recognition software to check the efficient filling of food-tray compartments. Similarly, it can be used for 100 per cent inspection of the heat-sealed cellophane cover over the finished dish. An added function could be laser marking of a bad item so that it can be removed at the inspection station".

Large scale highly automated production system is only amenable to the above inspection technology and batch operators have to still depend on manual inspection to weed out under processed samples. Design of a separate "non-destructive"system based on presence of a live marker organism in processed samples may be better suited for small operators who can subject the finished products to such a diagnostic unit to confirm about their sterility. Whether this is technically feasible can be known only if efforts are directed at innovating such a tool.


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