WHITE PAPER Metal detectable plastics use in cleaning tools and utensils - does it reduce foreign body risk? Debra Smith, Global Hygiene Specialist, Vikan A/S, Rævevej 1, 7800 Skive, Denmark BACKGROUND Foreign body contamination of foods can be a safety or quality issue, or both. Regardless, if a food is con taminated by a foreign body, the repercussions for the food business can be expensive and damaging. Metal detection is a well established and effective method of reducing the risk of metal fragments in commercial food products. Control of plastic foreign bodies is more difficult. Metal detectable plastics have been developed with the intention that metal detectors can also be used for their detection but how detectable are these plastics? In collaboration with Detectronic and Mettler Toledo, manufacturers of metal detection systems, and Zwick Roell, a materials testing group, Vikan have investigated the detectability of metal detectable plastics. The investigations focussed on two key areas, 1) the detectability of different metal detectable plastics and 2) the detectability, durability, functionality and clean ability of metal detectable plastic brush bristles. DETECTION TECHNOLOGY Many food manufacturers are unaware that the metal detectability of any metal containing foreign body will depend on a number of things, including the; • vibrations (physical and electronic) • metal content of the contaminant, both the quantity and type of metal • size of the metal containing contaminant • orientation of the metal containing contaminant • food product – size, composition • food packaging • speed of the conveyor belt • detector used • detector calibration Each of these interfering factors has an effect on the detectability of the metal containing contaminant and the interferences are often cumulative and inde pendently variable, as illustrated in Figure 1. Physical/ electronic vibrations Food product signal · Water content · Salt · Grease · Packaging · Bones · Frozen · Etc. Conveyor speed Figure 1. Factors affecting the metal detectable threshold Aperture size Detector type Fragment size/ orientation/ position in the food Metal content Detection threshold Vikan A/S - Department of Research & Development 1 Copyright © 2021 Vikan A/S · All Rights Reserved
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