The objective is to quantify the production. If it a matter of needing to measure the production of a number of machines, all of which feed their output to a common cooling area? If so, then it is necessary to count the product while it is still hot. However, it may also be feasible to move the sensor down the line where the heat is not such a problem.

There is one more possibility, but it might be a challenge to implement with an 8052. Digital imagery and "smart" software could optically count the product. The technique involves defining an area of an image to be "observed", and responding when the pixels in that area change. It is a technique that is used for optical motion detection, and it is especially effective in areas where motion is acceptable near, but not in a given area (for example in a museum where no one is allowed to reach inside the display). It certainly isn't the simplest solution, but it might be interesting to consider. Using an IR camera would certainly give you plenty of contrast.