Columns

Food Safety: Getting rid of unwanted foreign materials

February 1, 2009
/ Print / Reprints /
ShareMore
/ Text Size+
More buyers are demanding all products be passed through a metal detector.



According to an old joke, “What’s worse than finding a worm in your apple?” The answer: “Half a worm.” No one likes finding surprises in their food. Processors devote time and effort to ensure foods do not contain unpleasant surprises. In most cases, foreign materials, such as an insect in canned vegetables or a hair in a cookie, are harmless if eaten. However, when consumers uncover these surprises, it can be traumatic and expensive for the processor.

Glass, hard plastics, stones, pieces of metal, bone, seeds, pits and wood can cause injuries to the mouth, teeth and worse if swallowed. According to FDA guidelines for hard and sharp objects, items sized between 7.0 and 25mm are deemed unsafe. Items smaller than 7mm rarely cause injuries, except with infants, and those greater than 25mm don’t fit well in the mouth.

In agricultural processing, operations are designed to remove foreign materials during receiving. Harvesters pick up everything: birds, rodents, snakes, glass, rocks, etc. Plus, systems such as wash tanks, air blowers, destoners, float tanks using a compound like salt to alter the specific gravity of water, magnets, flumes and other devices help ensure undesirable items are removed. A final wash or rinse before processing helps remove even small materials. However, despite these efforts, sometimes items manage to get though. For example, the produce industry has occasional problems with small frogs that stick to the greens and end up in bagged products.

Over the past decade, food processors have focused their attention on foreign material detection due to the desire to ensure food quality and safety while meeting buyer requirements that include all products be passed through a metal detector. The exception is fluid products and powders that may be passed through in-line detector systems. These detectors are used when processing bulk materials, although some operations utilize detectors with gates large enough to handle 50-pound sacks.

When installing a metal detector, food processors should work closely with the equipment manufacturer to ensure the unit is not only properly installed, but operating at optimum sensitivity limits. For example, if a processor decides to use a metal detector on 50-pound bags of powder or cases of frozen entrées, minimum sensitivities may start at 4.0mm for ferrous metals. This would meet FDA guidelines for hard and sharp objects, but might not satisfy a buyer. Operating at lower sensitivities may result in false positives. Consequently, processors should have the manufacturer provide a letter defining minimum sensitivities for the system. The system should also be validated so there is supporting data that demonstrates performance.

Of course, many products, such as items using metalized film for packaging and some recycled paper products used for secondary packaging, cannot be passed through a metal detector. In these cases, as well as other applications, X-ray technology is a viable option. These machines not only find bits of metal, they also detect stones, glass and bone. Other available detection tools include in-line screens, sieves and magnets.

Food processors need to select the equipment for foreign material control that best meets their needs and the demands of their buyers. However, if a buyer’s demands are too extreme, the processor must be able to demonstrate that its system is equal to or better than what the buyer demands.

Did you enjoy this article? Click here to subscribe to Food Engineering Magazine.

Recent Articles by Richard Stier, Contributing Editor

You must login or register in order to post a comment.

Multimedia

Videos

Image Galleries

Plant of the Year 2014

Blue Diamond Growers was chosen as Food Engineering's 2014 Plant of the Year. The Sacramento-based company is the world’s largest producer of almonds and almond ingredients.

Podcasts

Burns & McDonnell project manager RJ Hope and senior project engineer Justin Hamilton discuss the distinctions between Food Safety and Food Defense as well as the implications for food manufacturers of the Food Safety Modernization Act.
More Podcasts

FSMA Audit

What is the is most important step you have taken to become ready for a FSMA audit?
View Results Poll Archive

Food Engineering

FE September 2014

2014 September

The September 2014 issue of Food Engineering explores how lean manufacturing, quality improvements and increased automation helps processors meet rapidly changing demands. Also, read how robotics, advanced machine controls, software and OEE are just a few of the tools that can boost productivity on packaging lines.

Table Of Contents Subscribe

THE FOOD ENGINEERING STORE

Food-Authentication-Flyer-(.gif
Food Authentication Using Bioorganic Molecules

This text provides critical tools and data needed to augment routine food analysis and enhance food safety by aiding in the detection of counterfeit, and potentially deleterious, foods.

More Products

Clear Seas Research

Clear Seas ResearchWith access to over one million professionals and more than 60 industry-specific publications,Clear Seas Research offers relevant insights from those who know your industry best. Let us customize a market research solution that exceeds your marketing goals.

Food Master

Food Master Cover 2014Food Master 2014 is now available!

Where the buying process begins in the food and beverage manufacturing market. 

Visit www.foodmaster.com to learn more.

STAY CONNECTED

FE recent tweets

facebook_40.pngtwitter_40px.pngyoutube_40px.png linkedin_40px.pngGoogle +