<FONT color=red>[QA Web EXTRA]</FONT> Metal Detectors: The Purchasing Decision

The basic premise of the metal detector has not changed a great deal through the years, but today’s equipment generally is more resilient, more automated and more technologically advanced.

QA managers used to purchase whatever would stand up to the conditions in their plant, said Tim Bowser, an associate professor at the Oklahoma State University BioSystems Engineering Department and a food process engineer, but today, systems are more resistant to environmental conditions and provide processors with more options.

Bowser said potential buyers should focus on six key points before making a metal detector investment.

1. The aperture. Look for the unit with the smallest possible opening for your product because it will have the greatest sensitivity. If possible, consider ways of making the profile of your product smaller at the point at which it will go through the metal detector to get the most sensitivity possible (e.g., split streams with multiple metal detectors, size sorting and reorientation).

2. A totally integrated system. “There has to be a way to mark or reject the string of product with the metal contaminant in it,” Bowser said. Consider, too, the proximity of metal and moving parts; while a rejection system requires moving parts, there can be no metal within a specific range of the detector itself.

3. Self-testing. A great deal of labor can be expended in testing, but even more is required if a test fails and every product since the previous test has to be rechecked or reworked. Automated testing can save a great deal of time and manpower for the plant.

4. Ease of interface. Minimizing the amount of pre-programming and “plugging in numbers” makes use much simpler for operators, particularly if multiple products are run on the same line.

Safeline’s National Sales Manager Oscar Jeter agreed, particularly when it comes to new employees. With the industry’s high turnover rate, new personnel must be able to understand the operation of a unit very quickly. If the machine is complicated and difficult to set up, you set yourself up for problems, he said.

5. Data retrieval. Can testing and results be easily documented and verified? Documentation is critical in today’s food supply chain, and, Jeter added, “a computer print out is probably a lot better than stacks of hand-written sheets.”

6. Washdown integrity. This feature is especially important in meat, poultry, dairy and similar plants where frequent heavy-duty washdowns are needed to maintain quality.