1. TECHNOLOGY
FOOD
36 may 2011
F
ood safety is a prerequisite without which food indus-
tries could not produce. When thinking of food safety,
the first things that ring a bell in one’s mind are mi-
crobiological hazard (pathogenic contamination) and
chemical hazard (contamination through toxic chemi-
cals such as phytopharmaceuticals, mycotoxins, material that mi-
grates from the package to the foodstuff, etc.), but there is another
important aspect that is often underestimated: the physical haz-
ards, that’s to say the presence of foreign bodies of different kind.
H.A.C.C.P. criteria are mainly oriented towards the prevention of
microbiological hazards, but their observance in compliance to
Art. 5 of the EC Regulation 852/2004 involves that “a food busi-
ness operator shall identify and prevent risks”, hence all kinds of
risks must be taken into account. Next to the self-control hand-
book, there are voluntary certifications such as UNI EN ISO 9001,
which outline the requirements for Quality Management Systems
that enhance customer satisfaction, for expanding the company
vision to all production processes, for delivering products of stand-
ard quality complying with the set requirements, the importance
of constantly improving performances, know-how and process
control, the capacity of involving the human resources in the pre-
vention of all kinds of hazards and risks. There are many other
voluntary certifications, which become essential when the prod-
ucts are directed to retailers. In fact, many supermarket chains
that sell many products with their own label, are very demand-
ing when protecting the confidence customers have in their trade-
mark. This need almost always turns into the request for Euro-
pean IFS (International Food Standard) and BRC (Global Stand-
ard for Food Safety del British Retail Consortium) certifications.
The scope of IFS Standards is to enhance the selection of branded
food suppliers in retail chains on the base of their capacity of sup-
plying safe products, complying with contract specifications and,
obviously, with food safety standards and existing laws. The IFS
standard is accepted in Europe and worldwide, as well by the GFSI
(Global Food Safety Initiative), an international initiative which
sets requirements for food safety schemes in order to improve
cost efficiency throughout the food supply chain. Recently, the
GFSI announced that several international retailers have come to
a common acceptance of the four GFSI benchmarked food safe-
ty schemes, aligning common criteria defined therein, with the
objective of making food manufacture as safe as possible while
reducing the duplication of audits. IFS standards specifically re-
quest the use of metal detectors. The BRC, another GFSI accept-
Metal detectors installed on production lines
protect consumers from physical damages,
and the manufacturer from image damages
and, hence, economical damages. They help
food processing industries to insure product
quality, but all other preventive measures to
avoid the presence of foreign bodies - such
as accurate maintenance to the production
plants, selection of incoming materials and
suppliers and continuous personnel training
- should not be neglected
Metal detector
In-line control
for a safer product
by Flavio Gibilras
2. 37
may 2011
ed standard, was developed in 1998 primarily to ensure that all
branded products are produced according to well defined qual-
ity standards, in full respect of minimum requirements. It can be
compared to a standard linking qualified suppliers to the retailer.
BRC certification is a must for exports to European countries, and
is an established guarantee of a company’s reliability. Non-Euro-
pean markets, as for instance the U.S. market, show almost ma-
niacal attention to the total absence of foreign bodies, definitely
higher than the attention devoted to the presence of residual vet-
erinary drugs. Companies intending to market their products on
those markets, must pay particular attention to physical hazards.
Physical hazards: presence of foreign bodies
Physical hazards refer to accidental food contamination with for-
eign objects (such as pieces of glass, metal, plastic, or wood),
and biological objects (insects, fragments of reptiles or rodents,
etc). While the microbiological and
chemical hazards are almost always
taken into account and often mon-
itored continuously, the physical
hazards can result from accidental
events, and are not easily foresee-
able, so that they cannot always be
avoided even with the best preven-
tive systems. Furthermore, while
a microbiological or - above all -
chemical contamination of minor
level may not be noticed by consum-
ers, the presence of a foreign body
in food triggers an immediate sense
of revulsion and loss of consumer
confidence in the manufacturer. In
case of such a non-conformity, the
manufacturer’s damage in terms of
numbers would certainly be limited
(the presence of fragments generally
covers only a few packages), but no
less serious than the damage to the consumer, to business cus-
tomers if the food is within a production chain, and, inevitably,
damage to the image. Physical hazards, like microbiological and
chemical hazards, can be reduced by implementing good preven-
tion and product/process quality management systems, including
accurate selection of raw materials, constant maintenance of pro-
duction plants; early identification of possible sources of foreign
bodies; personnel training, etc.
Metal inclusion prevention procedures:
metal Detector
Metal contamination in food can be very dangerous to the con-
sumer, as they can cause injury to the teeth and gums, as well as
more serious damages when ingested, if the fragments are sharp
or pointed. Their presence can be considerably reduced or almost
eliminated thanks to the continuous in-line control by means of
“metal-detectors”, as each package can be controlled individually.
Metal detectors have become indispensable tools for food process-
ing firms in order to comply with the requirements of voluntary
certifications and as self-protection from possible non-conformi-
ties caused by the presence of metal foreign bodies in processed
foods or in the raw materials, semi-finished products and packag-
ing materials delivered by their sup-
pliers. Contamination can derive
from a variety of sources, and even
an accurate visual inspection might
not be able to detect the presence
of small metal parts. Most industrial
metal detectors are based on the so-
called “balanced coil” concept: three
coils are mounted inside the detect-
ing head; one produces a modulat-
ed electromagnetic field, whereas
the other two receive this signal and
detect any changes caused by the
presence of metal parts among the
products passing through. A passing
metal part causes a disturbance of
the electromagnetic field received by
the coils. When the disturbance ex-
ceeds the threshold value (that has
been predetermined during calibra-
tion), the contaminated product is
