Foreign Object Detection Technology Update:
Multiscan Metal Detection
Finding metal foreign
objects in food is vital to food
safety and quality. Inspection
for such contaminants is
usually located at the end
of the line as the last line of
defense before a product is on
its way to the consumer. Yet,
1- to 2-frequency digital metal
detectors, ubiquitous in food
plants over the past 25+ years, have come with key barriers to achieving 100
percent metal-free products. Among the most difficult applications are dairy,
meat, poultry, and bread.
1. Finding anything, anywhere in any product—all of the time: Consider the
production volume in one of your lines in just one day and the different
types of metal that might be in your factory or in the ingredients.
2. The use of electromagnetic fields to find things that are magnetic and
conductive: Most food products are wet, have salt, or contain minerals,
which, when subjected to electromagnetic fields, also look magnetic and
conductive. Therefore, ignoring the product and finding the metal are not
3. The very small signals from small metal foreign objects: When a factory
has many possible noise sources, they can confuse the metal detector
electronics and software.
A new approach to metal detection—called multiscan—overcomes the
limitations of previous technologies. At the critical control point in your
process, this new technology can scan up to five completely adjustable
frequencies at a time to find metal types and sizes that were previously
undetectable. The result? Reducing the probability of an escape by many
orders of magnitude. Think of it as having up to five metal detectors back
to back in your production line; with multiscan, metals undetectable at one
frequency can be detected at another.
To learn more about multiscan, available now in the Thermo Scientific
Sentinel Multiscan Metal Detector, visit www.thermofisher.com/SentinelFSM.
from the market following 56 food
recalls because of extraneous materials
from 2015 to 2017.
Causes of Physical Contamination
Physical contaminants in food could
come from either external sources, such
as metal fragments, or internal sources,
such as bone particles and pits. They
Investigation and Identification of
can be introduced into food products
accidentally during harvesting or at any
point during processing due to poor
procedural practices anywhere in the
food chain, including manufacturing,
storage, transportation, or retail. The
so-called Dirty Dozen, the 12 most
common foreign material contaminants
in food, are glass, wood, stones, metal,
jewelry, insects/filth, insulation, bone,
plastic, personal effects, bullets/BB
shot, and needles. 5 Table 1 provides a
summary of common sources.
Food companies work hard to keep
their products free of contaminants.
Investigation and control of physical
contaminants in food should be conducted throughout the whole processing
chain or in food testing laboratories.
With accurate and timely information, a thorough investigation can be
carried out in testing laboratories in a
cost-effective and efficient manner. It is
essential to have a professional investigation team with appropriate resources
and equipment to help food company
quality assurance staff troubleshoot
consumer complaints and answer questions as to what the contaminants and
their sources are. It is often necessary to
apply integrated, multidimensional approaches for complicated investigations.
Comprehensive investigation can demand microscopy-based examinations
plus chemical techniques, on-site examinations, Fourier transform-infrared
(FTIR) analysis, and other techniques.
The investigation processes and screening procedures depend on the particular
physical contaminants and their sources. The procedures can be combined or
modified methods found from the following: AOAC International, American
Spice Trade Association, FDA’s
Mac-roanalytical Procedures Manual, FDA’s
Laboratory Information Bulletins, USDA’s
foreign matter identification documents, the United States Pharmacopeia,
and other compendious sources.
In general, special investigation pro-
• Inspect and target suspected sources
of physical contaminants
• Identify the foreign matter
• Determine or evaluate the root cause
These procedures consist of eight
1. Target contaminants. In many
cases, it is necessary to select a suitable