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McGill University
Macdonald Campus
Department of Bioresource Engineering
BREE 535-Food Safety Engineering
Professor Michael Ngadi
Group 1 Burelle, Ian 260 472 128
Riskulov, Erbolat 260483038 Stanger, Dillon 260411556 Walker, Katie 260409484 Wattie, Bryan 260313966
06 December 2013
DETECTION OF FOREIGN BODIES IN GROUND MEAT OPERATIONS:
A LITERATURE REVIEW AND PILOT PLAN
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DETECTION OF FOREIGN BODIES IN GROUND MEAT OPERATIONS:
A LITERATURE REVIEW AND PILOT PLAN
Department of Bioresource Engineering, Macdonald Campus, McGill University, Ste.-Anne-de-Bellevue, Quebec
I. Burelle, E. Riskulov, D. Stanger, K. Walker, & B. Wattie
**Excluding the table of contents, this paper is 15 pages before the references.
EXECUTIVE SUMMARY
Ground beef has been tainted by biological, chemical, and physical contaminants in the past. The paper will begin by
briefly describing a few case studies where ground beef has been contaminated, followed by the general process used for
beef grinding. The focus will then shift to outline two innovative technologies which can detect foreign bodies in ground
meat: surface penetrating microwave detection, and ultrasound. It will discuss which technology would be best suited for
physic in meat grinding. The paper concludes with the chosen detection method as applied to a theoretical pilot processing
facility.
TABLE OF CONTENTS
Executive Summary ............................................................................................................................................................................. 2
1. Food Safety Issues ............................................................................................................................................................................ 3
2.0 Ground Meat Process Flow ............................................................................................................................................................. 4
2.1 Reception and Storage ................................................................................................................................................................ 4
2.2 Initial Grinding ........................................................................................................................................................................... 5
2.3 Blending ..................................................................................................................................................................................... 5
2.4 Final Grinding ............................................................................................................................................................................ 5
2.5 Packaging/Freezing..................................................................................................................................................................... 5
3.0 Novel Technology Review ............................................................................................................................................................. 5
3.1.0 Microwave Detection ............................................................................................................................................................... 5
3.1.1 Introduction ......................................................................................................................................................................... 5
3.1.2 Mechanism of Operation ...................................................................................................................................................... 5
3.1.3 Parameters in Design ........................................................................................................................................................... 6
3.1.4 Application .......................................................................................................................................................................... 7
3.1.5 Merits and Demerits ............................................................................................................................................................. 8
3.1.6 Conclusion ........................................................................................................................................................................... 8
4.2.0 Ultrasound ............................................................................................................................................................................... 8
4.2.1 Introduction ......................................................................................................................................................................... 8
4.2.2 Mechanism of Operation ...................................................................................................................................................... 8
4.2.3 Parameters of Design ........................................................................................................................................................... 9
4.2.4 Application .......................................................................................................................................................................... 9
4.2.5 Merits and Demerits ........................................................................................................................................................... 10
4.2.6 Placement .......................................................................................................................................................................... 10
4.2.7 Conclusion ......................................................................................................................................................................... 10
5.0 Discussion .................................................................................................................................................................................... 10
5.1 GMP Guidelines ....................................................................................................................................................................... 11
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6.0 Pilot Processing Facility Process Flow and Detection ................................................................................................................... 12
6.1 Initial Grinder Alterations ......................................................................................................................................................... 13
6.2.0 Contaminant Removal ........................................................................................................................................................... 13
6.2.1 Magnetic Removal of Ferrous Metal .................................................................................................................................. 13
6.2.2 Mechanical Removal of Bone Chips .................................................................................................................................. 14
6.3.0 Microwave Detection and Foreign Body Removal ................................................................................................................. 14
6.3.1 Placement .......................................................................................................................................................................... 14
6.3.2 Mechanism of Operation for Microwave Detection oF Foreign bodies ............................................................................... 14
6.3.3 Parameters of Design for Microwave Detection ................................................................................................................. 15
6.4 an Alternative Detection method- Microwave and Ultrasound .................................................................................................. 15
7. Conclusion ..................................................................................................................................................................................... 16
8. Works Cited ................................................................................................................................................................................... 16
9. Appendix ........................................................................................................................................................................................ 18
1 . FOOD SAFETY ISSUES
Pathogens such as E. coli O157:H7 have been known to
proliferate on ground beef, amongst other forms of
pathogens. Jack in the Box had a large E. coli O157:H7
outbreak which killed 4 people and caused nearly 600
people across 4 states to be admitted to the hospital with
bloody diarrhea. The culture tests proved positive that
the source was ground beef from the food chains (Flynn,
2009).
Beyond the bacterial contamination, the moving metallic
parts used in the cutting of beef, and further grinding of
beef, expose the meat to further chemical and physical
contamination sources (from lecture notes). For
example, in Michigan in 2003, a nicotine contamination
was found in ground beef, poisoning 96 people and
sending to 2 to the intensive care unit. The
contamination was traced back to a pesticide containing
nicotine called Black Leaf 40 © (CDC, 2003).
Contamination of foreign bodies represent over 40 % of
all food defect prosecutions from 1988 to 1994 (Figure
1a) (Graves et al., 1998), and within those 24 % related
to metal, 10 % to glass, and 6% animal (Figure 1b). In
2006 in Pennsylvania, 6 cases of foreign objects in food
occurred, five of which were the result of ground beef
during a 2 week period in January. The foreign objects
within the contaminated beef product were found to be
were metal or glass, but also included a hunting pellet in
the ground beef (Young, 2006). More recently 89720
pounds of ground beef were recalled this past September
by the Central Valley Meat Company as a consequence
of an investigation by the FSIS. (USDA, 2013). The
massive recall was the result of plastic shard foreign
bodies contaminating some marketed product. As such,
it is clear that there is an increasing need for physical
contamination detection to alleviate the growing
prevalence of ground beef adulteration. Hence the focus
of this paper will be on the detection of physical
contaminants within ground beef product. Physical
contaminants, such as glass, bones shards, or small scrap
mill metals, are equally as dangerous as foodborne
pathogens and thereby demand an equal effort to control
and prevent such occurrences.
The food industry has made many strides in the
detection of physical contamination. The increased
variance and availabilities has improved detection
versatility and capability. Detection methods have a
wide range: magnetic, electrochemical, optical, to simple
physical methods (see Table 1).
Figure 1a
Causes of food defect prosecutions (UK).
(Graves et al., 1998)
4
Figure 1b
Types of contaminants leading to prosecution (UK).
(Graves et al., 1998)
Table 1
List of detection methods and their properties:
wavelength, food product, foreign bodies detected, and
availability. (Graves et al., 1998)
2.0 GROUND MEAT PROCESS FLOW
The process flow of ground meat operations includes:
(1) raw material handling, (2) initial grinding, mixing
and cooling, (3) final grinding, (4) transport to formers,
and, finally, (5) packaging and storage (Figure 2.0). As
focus of this paper is on grinding specifically, steps (2)
and (4) are primarily of interest.
Figure 2.0
From Assignment 1
2.1 RECEPTION AND STORAGE
The raw material can enter the plant in either a frozen or
a fresh, but still refrigerated, state. The raw material will
be visually inspected for foreign matter such as bones,
metal, or anything else dangerous to the consumer or
product quality. Smelling is also part of the preliminary
verification. Furthermore, the material is sampled and
brought to the laboratory for testing. Testing includes
microbial enumeration and identification. If substandard
levels of bacteria are present, the shipment will be sent
for other usages such as ready-to-eat meals.
Ready-to-eat meals are cooked or otherwise include a
kill step; which inactivates the bacteria before they
proliferate to dangerous levels. Cooked food with proper
packaging and proper storage, usually freezing, will keep
the food stable and safe. Additionally, if it were to
remain raw and ground, the beef would have become –
potentially – a risk to food safety. This testing allows
meat processing operations to minimize their losses.
5
Sample testing is continually conducted to check for
even small amounts of pathogens. Finally, the lean-to-fat
ratio is also determined. All this testing allows the plant
to verify the quality and reliability of each of its
suppliers as well as allowing for product grading.
Once the raw material has been received, inspected, and
sampled, it will be stored in the same state upon which it
was received – i.e. frozen will remain frozen and fresh
will remain as such – until it can be sent to the grinder.
2.2 INITIAL GRINDING
This unit operation involves bringing the beef to a coarse
grind in preparation for the next operation. Here coarse
grind is defined by a breaker plate opening of ¼ to 1
inch in diameter. The size depends on the ratio of frozen
or fresh beef, or alternatively entirely frozen or fresh
composition. The desired composition of fat to lean
muscle tends to be that of less fat. Adjustments can be
made later, during the blending operation to make sure
the composition is ideal in terms of fat content.
2.3 BLENDING
The biggest control factor for this unit operation is the
lean-to-fat ratio. Since the composition can change
dramatically from one shipment of raw material to
another this step allows for product consistency.
Moreover, in some cases food additives and ingredients
can be included in during this step. Several calculations
of how much coarse grind fatter beef needs to be added
are performed until a thoroughly mixed, and uniformly
blended batch demonstrates the desired characteristics.
2.4 FINAL GRINDING
Here the beef is brought to the desired size depending on
its purpose. Bone chip and gristle eliminators are an
integrated part of the process to avoid physical
contaminations.
2.5 PACKAGING/FREEZING
If the product is to be sold fresh, clean Styrofoam and
plastic wrap is used for packaging. Otherwise in the case
freezing, there are several options. Cost is important to
consider along with the applicable food safety standards
when deciding on packaging. It is suggested that a
mechanical/blast freezing method be used for frozen
beef products . The process involves using ammonia as a
refrigerant to produce very cold air which is then blown
at high velocities on the beef patties (or other forms of
ground beef) to bring it to freezing temperatures
extremely fast. This reduces the amount of damage
which might occur to the product if frozen slowly, as
well as freezer burn. The process is similar to cryogenic
freezing but on a budget.
3.0 NOVEL TECHNOLOGY REVIEW
3.1.0 MICROWAVE DETECTION
3.1.1 INTRODUCTION
Electromagnetic waves have been used for detection
since the 1930s in military applications (Arvanitoyannis,
2004ch. 10 , p. 173). The pulp and paper industry uses
microwave technology to detect metals, a physical
contaminant of interest for our team (Salvade et al.,
2008). Microwave technology has applied for food
quality since the 1960s (Arvanitoyannis, 2004). In
Switzerland in the early 2000s, dialogues between food
companies accented the issue of “undetectable objects,”
due to the increase usage of products like plastic
(Reimers, 2012). The Swedish Institute for Food and
Biotechnology (SIK) conducted research on possible
solutions using microwave technologies. With the help
of industry experts a prototype was developed and later
installed in food processing facilities by Food Radar
Systems AB.
Lower power microwaves which are used for detection,
use microwave loads much lower than radiation limits
and power for heating (Arvanitoyannis, 2004, p. 172).
The frequency used ranges from 1010
–1012
Hz (Graves et
al., 1998). This allows for minimal thermal and, thereby,
quality impact of such as method.
3.1.2 MECHANISM OF OPERATION
Metals are good electrical conductors and good
reflectors of microwave while dielectrics function as
good electrical insulators and good absorber and
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transmitters of microwaves (from BREE 325 course
slides). Additionally, water has high dielectric loss.
Microwaves propagation is affected by temperature,
dielectric constant (ε0), and dielectric loss (ε’’) .The
transmitted microwave field passing through a product,
detects variation in dielectric properties between the
product and the different materials comprised in the
foreign bodies.
The equation governing wavelength is as follows:
(3.1.1) (Arvanitoyannis, 2004, p. 173)
Where,
If the wave is propagated through a vacuum, as soon as
the wave reaches a surface, the wave experiences
exponential damping (Figure 3.1.2) (Arvanitoyannis,
2004, p. 176). The shortening of the wavelength in
medium can easily seen when compared with the wave
propagated through the vacuum. This effect is similarly
produced when waves are propagated through a food
medium and the wave encounters a foreign body.
Figure 3.1.2
Propagation of electromagnetic radiation in a medium.
(Arvanitoyannis, 2004, p. 180)
A reference measurement is made on a medium with
foreign bodies absent (Arvanitoyannis, 2004, p. 180).
When comparing data of a medium including foreign
bodies to the reference data, the deviation of reference
data will indicate a presence of a foreign body. The
scattering produced by the microwaves is strong if the
foreign body contains sharp edges, which can be used to
locate bone, plastic or glass chips. This detection method
is only effective if the dielectric function of the foreign
body is different than the food product, such as in wet
foods. In wet foods the relative function is about 80,
whereas in plastic is about 2.5 and glass up to 10. Dry
foods, such as spices, have a real part of the relative
dielectric function in the range of 1 or 2.
3.1.3 PARAMETERS IN DESIGN
A schematic on mechanism behind microwave detection
is presented below in Figure 3.1.3. The food container is
transported on a conveyor belt through the measurement
gap (Arvanitoyannis, 2004, p. 181). The microwave is
generated in the transmitter module (right side of the
conveyor belt) and retrieved in the receiver module (left
side).The data is evaluated on computer.
Figure 3.1.3
Schematic of the food radar set-up.
(Arvanitoyannis, 2004, p. 182)
In the detector design, it is important to consider the
field distance (the distance between the antenna
propagating the microwave and the food
(Arvanitoyannis, 2004, p. 181):
(3.1.3)
Where,
The authors found that measurements at a single
frequency and their respective damping in the food
7
material were not sufficient to detect foreign bodies
(Arvanitoyannis, 2004, p. 181). In addition, it is
necessary to measuring wave damping and wave runtime
at different location of the food medium and at different
frequencies to gather enough absorption and diffraction
data. Recent developments in tunable and inexpensive
chip microwave generators ease the task of performing
multi-frequency measurements. A foreign body detector
will operate at around 2.5, 5.8 and 9.9 GHz (p. 182).
3.1.4 APPLICATION
A microwave detector of foreign bodies in food provides
multiple applications in food safety. It is also a quick
method for food quality evaluation, such as detecting the
presence of nuts in chocolate nut praline
(Arvanitoyannis, 2004, p. 183). The detector can also
sense production failure if the food content changes too
drastically.
Placement of detection equipment is the choice of
management (Arvanitoyannis, 2004, p. 183). If the
detector is placed after the packaging and sealing stage it
allows for a ‘final checkup’ before the products leave the
facility. If foreign bodies are later found in the product,
the producer can prove that the contamination was
inserted after sealing and packaging, reducing total call-
back of a batch of product. Placing the detector at an
earlier stage allows for detection of foreign bodies
earlier in the production line. This provides the option of
rejecting some of the product before it is made into the
final product. Another possible site is at the entry
acceptance of delivered goods. This location is
especially apt for our product, ground meat, a raw
product which might arrive at the facility with physical
contamination.
In microwave detection must be adoption differently
depending on the specific applications (Arvanitoyannis,
2004, p. 183). The technology depends on whether the
substance is wet or dry, processed in batches or
continuously, is homogeneous or non-homogeneous. A
product is considered dry if the water content is less than
5%. Ground meat is considered wet as it is generally
above 50% water. High water content results in a high
dielectric constant in the product compared to dry
products, so optimal resolution is not affected by
frequency, but it is still important to optimize the
microwave frequency carefully for successful detection
of foreign bodies. A products is considered
homogeneous if its graininess is much smaller or
roughly the same as 1/2 of the microwave in the food
medium (p. 184). For an edge length of food grain and
foreign body, dfood dFB respectively with their respective
dielectric contrast to air: εrFB and εrfood.
(3.1.4)
Margarine, cheese spread, plain chocolate bars and dried
spices such as oregano or thyme are examples of
homogeneous materials suitable for microwave
detection. In ground meat, our team might consider
placing a detector after the grinder so that the meat is
homogenized properly for easy detection of foreign
bodies (p. 184).
The following table represents the ability for microwave
device to detect foreign bodies in different media. The
table shows that the foreign bodies involved in our
team’s product, ground meat are detectable. Bone chips
can be detected 1 mm x 2 mm x 3 mm, glass 30 mg, and
metal 10 mg for a similar product of minced meat
(Table 3.1.4a) (Arvanitoyannis, 2004, p. 185).
Table 3.1.4a
Laboratory results describing radar detection on different
foreign bodies in food.
To achieve the maximum sensitivity of the detection
method requires the generation and maintenance of
reference data, in order to minimize the dielectric error
of food which keep the detrimental dielectric error
(Arvanitoyannis, 2004, p. 186). To do this, it is best to
determine an average dielectric distribution of a large
8
number of samples, assuming that the individual
dielectric functions are normally distributed.
The following Table 3.1.4b describes the set up for
different components of microwave foreign body
detection (Arvanitoyannis, 2004, p. 182):
Table 3.1.4b
Parts and components of radar systems in food
processing.
The chart provides the components our team could use
in designing a system for our product, ground meat.
3.1.5 MERITS AND DEMERITS
Microwave detection is certainly applicable for meat
grinding (Arvanitoyannis, 2004). Meat is generally
homogenized and has a sufficient moisture content to be
considered wet. These two aspects make microwave
detection effective against foreign bodies with differing
dielectric functions, such as the physical contaminants
which interest our team: plastic, metal, glass, etc.
However, when considering biological contamination
detection, microwave detection is insufficient. It is only
applicable to physical contamination on the scale of 1-
10mm. Detection of smaller physical contamination and
biological contamination requires the use of other
detection methods.
Unlike impedance detection, among others, microwave
detection is non-invasive and does not require probes to
be inserted into the food medium. This consideration is
important when considering the necessary sterile
environment for detection. In non-invasive methods,
there is no chance of probe contamination, fouling.
Additionally, there is no need to clean the probe to
eliminate biofilm build up.
Microwaves are limited by the characteristics of the food
medium and contaminant (Graves et al., 1998).
Specifically, this limitation arises from the difficulty in
distinguishing between a high-density sample of high
moisture with a low density sample with a low moisture
content. Perhaps combining microwave detection with
others (such as optical or ultrasound) may overcome this
issue.
3.1.6 CONCLUSION
Microwave detection of foreign bodies systems are
simple and fast at detecting a variety of metal and
nonmetallic foreign bodies (Arvanitoyannis, 2004, p.
188). Microwave detection is best suited for
homogeneous products. This method has been shown to
detect stones, steel, glass, and plastic in uniform
products at a size as small as 1 mm x 1 mm x 2 mm.
However, this method fails when the food’s dielectric
noise exceeds the contrast of the foreign body.
4.2.0 ULTRASOUND
4.2.1 INTRODUCTION
Ultrasound is another novel technology that may prove
beneficial in eradicating the safety challenges of ground
beef processing. As a post grinding analysis operation,
ultrasound would enable industry to detect physical
contaminants of various material compositions.
Ultrasound analysis is achieved by transmitting sound
waves into a food material. When the waves are
transmitted into the food product the acoustic impedance
is affected by the different constituent material (Basir et
al, 2004). This allows for the detection of foreign bodies
by analyzing the acoustic impedance changes that may
be present. There is a fast range of frequencies available
for ultrasound application but waves with a minimum
frequency of 20Hz (Jayasooriya et al, 2004) are
generally used for food based application.
4.2.2 MECHANISM OF OPERATION
For optimal ultrasound imaging the components of the
acoustic wave must be understood such that the correct
wave type is analyzed. The four components of the
9
acoustic energy are the compressive, shear, Rayleigh and
Lamb waves (Basir et al., 2004). Each of these waves
has a different velocities and propagation characteristics
which enable different application. Moreover, due to the
variable physical properties of food materials, the
transmission of energy becomes even more complex.
The latter challenge has been addressed by a proposed
volume-average method (Basir et al., 2004), simplifying
the density and adiabatic compressibility of the food
product. Additionally, in utilizing the extensive
background research on ultrasound technology and wave
application, it can be determined that shear and
compressive waves are of relevance for foreign body
detection (Basir et al., 2004). Both wave types can be
applied to solid and semi-solid products, although shear
waves are more tolerant on sensor alignment which may
cause problems for compression waves.
4.2.3 PARAMETERS OF DESIGN
The mechanical design component which allows the
transmission of energy to the inspected product is an
ultrasonic transducer. (Basir et al., 2004) It allows, as
with any transducer, for the conversion energy which in
this case is from electrical to mechanical. Depending on
the application there are a variety of systems available
for food processing. The majority rely on direct contact
applications with slurry or emulsion samples for
ultrasonic transmission. A promising alternative for solid
products is non-contact air-coupled transducers (see
Figure 4.2.3a and 4.2.3b) (Cho et al., 2003).
Figure 4.2.3a
Non-contact ultrasound transducers mechanism of
operation. (Cho et al., 2003)
Figure 4.2.3b
Laboratory setup of ultrasound detection.
(Cho et al., 2003)
4.2.4 APPLICATION
Ultrasound is one of the many novel technologies that
can be applied in a variety of fields ranging from food to
pharmaceuticals. For the purposed of this report the
potential for beef food safety applications is the area of
focus.
A recent study conducted analysed the use of ultrasound
for bone fragment detection (Correia et al., 2008). For
this experiment chicken breast was used as the sample
but the results were encouraging. Using a piston cylinder
apparatus, pulse echo ultrasonic measurements were
analyzed using a reflectometer (Correia et al., 2008).
Using this method, it was possible to detect bone
fragments within the poultry samples. Moreover the
process outlines the importance of amplitude ratio, not
velocity to the discrimination of different properties.
This would mean that a system with correct calibrations
would enable the identification physical defects within
muscle tissue
The use of non-contact air instability ultrasound has also
been tested for poultry application (Cho et al., 2003).
Using a non-contact system, much like what was
previously outlined in Figure 4.2.3a, it was possible to
calibrate sample attenuation and thereby assess the
change in attenuated energy caused by physical
contaminants (Cho et al., 2003). This allowed for the
determination of particulates of 3x3 mm2 (Cho et al.,
2003) to be identified, although it was difficult to
10
distinguish between fragments and natural internal
particulates. It has thus been posited that ultrasound
parameters can be further evaluated to better determine
the constituent material.
As a different research approach, ultrasound detection
been applied in the medical research using beef samples
(Schlager et al., 1991). This study used 6 cm3 beef
samples containing foreign bodies. By using an
ultrasound transducer functioning at 7.5-MHz, it was
possible to analyze the samples such that the different
physical components could be differentiated (Schlager et
al., 1991). Furthermore it had an encouraging 98%
detection rate (Schlager et al., 1991) in samples
contaminated with foreign particulates. It is important to
note that this is a high frequency than what is generally
applied to food application, yet still reinforces a degree
of efficacy for defect recognition. Based on these
findings it can be seen that the ultrasound may prove
more effective for physical contaminant detection in beef
product.
4.2.5 MERITS AND DEMERITS
The aforementioned studies lend themselves well to
potential for extrapolating ultrasound systems for a
ground beef processing operations. This technology
allows for physical material contaminates to be
identified with reliable results. Thereby ultrasound
would allow for a more universal detection system to be
integrated, decrease capital input required for different
material identification technologies. Additionally this
research reinforces the ability to evaluate meat products
that have variable physical constituents. As a post
grinding safety alternative, this food safety unit
operation could be integrated into a processing system to
detect the contaminants of high interest; glass, bone, and
metals (Schlager et al, 1991).
Ultrasound seems like it may be an ideal food safety
option but it is not without its challenges. The largest
hurdle for industry application is the high cost of such a
system. Systems such as these are intricate mechanical
devices that involve many complex design materials.
Not only are the transducers expensive but the required
computing technology is also a high cost consideration.
It requires trained personnel, appropriated software and
the physical hardware capacities. Another consideration
is the by-product effects that ultrasound has on
biological material. From a beef perspective there are a
variety of potential interactions related to the frequency
of processing, see Table 4.2.5, appendix (Jayasooriya et
al, 2004). This is a factor that could be controlled when
initially designing and integrating a system when the
frequency is chosen. Furthermore, the ultrasound is not
yet an extremely time efficient process. As ground beef
is not a liquid based product, on-line detection is has not
be effectively addressed (Rastogi, 2001). So in terms of
processing, it would be difficult and not currently
feasible to integrate directly. With that said, ultrasound
technology food based applications are continually being
researched. As research and development advances, so
will the technology, time requirements and software
abilities.
4.2.6 PLACEMENT
For maximized efficacy an ultrasound detection system
would be integrated as a post grinding operation, right
before the packaging phase. In placing in immediately
before the packaging operation, it would maximize
potential defect detection that may occur after the
grinding process. Ideally ultrasound analysis would be
integrated post packaging allowing for both the package
and beef to be analysis. Yet this is currently not a
feasible option due to the large about of material
differences that would greatly impact the correct
evaluation of the product. As such, if the safety of the
package can be ensured using a different safety process
and the ground product assessed using ultrasound, it
should be possible to minimize contamination.
4.2.7 CONCLUSION
Ultrasound imaging is a promising technology that may
be the future of food safety and quality operations. With
the continued work in this field of study, it is hopeful
that more systems of this type will enable the food
industry to improve current safety measures.
5.0 DISCUSSION
For the design of a pilot plant implementing these
technologies it has been decided to use microwave
detection. While both ultrasonic and microwave
11
detection systems have their limitations for in-line use
during manufacturing, microwave has many more
industrial applications, and is prime for adaptation to
ground beef safety. A microwave detector of foreign
bodies in food material provides multiple applications in
food safety. The detector can also sense production
failure if the food content changes too drastically.
Placement of detection equipment is the choice of
management. If the detector is placed after the packaging
and sealing stage it allows for a ‘final checkup’ before
the products leave the facility. If foreign bodies are later
found in the product, the company proves that the
contamination was inserted after sealing and packaging,
reducing total call-back of a batch of product. Placing
the detector at an earlier stage allows for detection of
foreign bodies earlier in the production line. This
provides the option of rejecting some of the product
before it is made into the final product. Similarly
ultrasound detection yields many of the same benefits as
the microwave detection. The major caveat is that
current technological status is not as developed as
microwave technology and may prove restrictive in
automated operations.
A point of high interest for physical contamination is the
potential for universality in detection technology. When
compared with conventional options, such as metal
detector, either novel technology hold the strong
advantage of versatility. Metal detection has a high
material specify which although very reliable, does not
lend itself to the detection of other foreign bodies. As it
is vital to address all types of physical contamination
sources, novel technology may be the key to integrating
an individual device that results in an increased material
detection array. Either technology highlight has potential
to be included in the food safety procedure of a ground
beef operation. In identifying the appropriate contexts
and constraints, such as GMPS, of the application the
optimal design can be determined.
5.1 GMP GUIDELINES
Good Manufacturing Guidelines (GMP) contains general
requirements and guidelines for producing food products
in sanitary conditions. In the United States, the
responsible agency for GMP in meat and poultry
processing is the USDA under regulatory authority that
has developed a sanitation regulation under Code of
Regulations Title 9 Part 416 addressing all sanitary
requirements. (9 CFR 416) Whereas, FDA enforces Title
21 Part 110. (21 CFR 110) Both regulations codes
provide for good manufacturing practices, however,
Title 9 CFR 416 is more applicable towards meat and
poultry processing. In a broader sense, GMP regulations
are designed to control the risk of contaminating foods
with filth, chemicals, microbes, and other means during
their manufacture.” (Keener, 2007) In general, each
establishment must be operated in such manner to
prevent unsanitary conditions and product
contamination. The categories from GMP guidelines that
are directly related to grinding are presented in Table
5.1a below.
Table 5.1a
GMP guidelines for ground meat
Category GMP Guidelines
1. Equipment and
Utensils
Processing equipment
& utensils Made of material to facilitate cleaning, kept in sanitary conditions
Easy-inspection-
engineering Must be constructed in manner to facilitate inspection process to
determine its sanitary condition Inedible equipment
material Constructed of material to prevent unsanitary conditions
2. Sanitary
Operations
Food-contact & non-
food-contact surfaces Must be cleaned sanitized as frequently as necessary
Cleaning chemicals Must be safe and effective and safety documentation accessible to
FSIS Transportation Must be protected from unsanitary environment
Canadian beef food safety systems are required to have
both prerequisite programs as well as HACCP models in
place, which is considered to be more case specific as
opposed to GMP measures which gives a general outline
12
in terms of product safety. These systems are audited by
the Canadian Food Inspection Agency to ensure that the
programs are in place and running effectively. The
aforementioned apply to both the slaughter and
fabrication processes which are treated as separate
entities and as such have different precautions associated
with them. For example slaughter processes have
specific controls for live animal inspection all the way to
spinal cord removal. Whereas GMP’s that are important
to the ground beef process are FIFO, smelling and visual
inspection. Plants must use a First In First Out (FIFO)
rotational basis. This procedure prevents any raw
material from being stored longer than it should while
ensuring the raw meat gets to the consumer as quickly as
possible with as little wasted storage time. Another
practice is that during grinding, smelling and visual
inspection are typically used to check for any
abnormalities. Temperature is meticulously monitored to
remain at, or very close to, -2.2 C. This temperature
minimizes bacterial growth and facilitates several
aspects of the grinding process. Considering how short
of a shelf life fresh beef has, this is a fundamentally
important process. Alternatively the fabrication
programs are more concerned with SSOP and packaging
processes. A generic HACCP model is attached in
Appendix A, however our project concerns itself with
grinding and the detection of foreign materials in the
beef. As such our design is primarily concerned with this
aspect of HACCP for ground beef.
Table 5.1b
(USDA, 1994)
As one can see from the Table 5.1b beyond basic metal
detection, many SSOP and HACCP protocols rely on
visual inspection, a job that is highly important yet
tedious. Thus it is susceptible to human error. Our
design would implement a more reliable detection
method to address Hazard number CCP 7-p (Table
5.1b), the detection of foreign materials. If bone chips
are found, in a high volume of meat, it can be resent
through the grinder so that the bone chip removal may
act once again on the product, however it is important to
consider the costs of doing so, and whether or not a
second pass is an economically sound decision.
However if metal or glass is found safe limits on the
boundaries of contamination must be determined, and
the contaminated meat must be destroyed. The safe
limits can be so far as to dispose of the whole batch, and
initiate a full SSOP.
6.0 PILOT PROCESSING FACILITY PROCESS FLOW
AND DETECTION
Our team developed an application of microwave
technology to a theoretical pilot meat grinding
processing facility. Detailed are the metal and bone
contaminant removal operations and setup of the
microwave detection device. This pilot design flow
begins with the whole meat arrival at the plant. The flow
continues to: (1) bone and metal contaminant removal
technology; (2) microwave detector and corresponding
pump design, and potentially (4) an alternative detection
design. The contaminant removal devices are the first
line of defense, removing most contaminants. The
detector functions to ensure complete removal of
contaminants, as it will detect any remaining bodies and
eject them. Our team included a microwave detection
technology already in industry. As the microwave design
was intended for less viscous food materials a ground
meat pump design in industry was included to make the
microwave detector system more applicable to ground
meat. A potential design makes a compromise between
microwave and ultrasound technology by using them in
tandem. This section also includes proposed grinder
alterations and detector placement.
13
6.1 INITIAL GRINDER ALTERATIONS
The grinder’s most important limitation is difficulty of
properly cleaning and sanitization. An industrial sized
meat grinder cannot be completely disassembled and
cleaned, so specific SSOPs for each model of grind
should be developed.
The helix may include corners or other areas in which
beef can accumulate, putrify, and proliferate pathogens.
The helix itself must be free of lips or sharp corners
where this buildup may occur. A smooth, continuous
helix, such as the image seen in Figure 6.1 would be
favorable. More importantly, the helix could be removed
from the grinder and cleaned separately along with the
breaker plate. These pieces could be completely
submerged and allow every surface to come into contact
with the appropriate cleaning agents.
Figure 6.1
Preferred smooth and continuous helix design for meat
grinding. (Junan, 2013 )
The container which receives and processes the meat
should have an SSOP that considers the following
aspects. This containment unit would be a completely
smooth and exposed surface. Nozzles with high pressure
high temperature steam could be placed strategically so
that when the grinder is finished operating they can be
turned on. The choice of steam is to minimize chemical
contamination. If the nozzles were to malfunction and
release during operation of the grinder, or other issues
arise, the only contamination is water. On the other
hand, hot water might compromise biological
contamination by bringing the temperature to a range
which fosters microbial growth. This is why a cooling
system is generally utilized and recommended in our
team’s pilot plan.
A simple system which involves keeping the motor far
from the grinding operation as well as proper cooling of
this motor is optimal. The large amount of energy and
torque required of the motor releases significant amounts
of heat which could compromise the biological safety
and stability of the product. Here is where ability to
rapidly cool the whole grinder is valuable, as it allows
for any temperature increase to be counteracted. Liquid
nitrogen can be applied to rapidly and efficiently control
temperature without chemical contamination. The liquid
nitrogen would not remain in liquid form, and therefore
exit the product as it turns into gaseous form. For ground
beef products, nitrogen is not a contaminant of high
consideration.
6.2.0 CONTAMINANT REMOVAL
6.2.1 MAGNETIC REMOVAL OF FERROUS METAL
Low intensity magnets are capable of separating large
ferrous pieces whereas more expensive high-powered
rare-earth metal magnets are capable of removing small
ferrous materials as small as a few microns (compared to
the 1-3 mm size measured by detectors). However,
magnets are less capable of removing spherical objects
(Arvanitoyannis, 2004). Either a gravitationally or
conveyer fed or metal separators (Figure 6.2.1a and b)
should be installed before the microwave detector to
remove metal as a first line of defense. Any detection of
more metal will result in the expulsion of the remaining
metal by the detector.
Figure 6.2.1a
The mechanism of operation for the gravitationally-fed
magnetic separator.(Arvanitoyannis, 2004)
14
Figure 6.2.1b
The mechanism of operation for the conveyor-fed
magnetic separator. (Arvanitoyannis, 2004)
6.2.2 MECHANICAL REMOVAL OF BONE CHIPS
The patent named “Rotary meat grinder with bone chip
removal hub,” U.S. Pat. No. 4,699,325, includes a
“perforated plate and a stud having a shaft portion
journalled in a cylindrical bore in the plate” (see Figure
6.2.2) (Hess, 1987). Any bone particles remain in the
grinder and are collected periodically. This patent
minimizes bone particle and gristle contamination with
minimal loss of meat as the contaminants are removed
separately from the meat. The integration of this removal
hub as well as an additional imaging technology
subsequent to the final grinding process may prove to
bolster ability to decrease physical adulation.
Figure 6.2.2
Rotary meat grinder with bone chip removal hub
(Hess, 1987)
6.3.0 MICROWAVE DETECTION AND FOREIGN
BODY REMOVAL
6.3.1 PLACEMENT
The placement of the microwave foreign body detection
is critical. For ground meat operations, we recommend
that the detector be placed just after the meat grinding.
Grinding homogenizes the meat making microwave
detection more effective. Furthermore, if physical
contamination removal technology (such as the Rotary
meat grinder with bone chip removal hub) removal is
installed in the grinder, placing the detector after the
grinding process is most apt, as the detector can evaluate
the bone remover’s efficacy. Finally, Chris Fuller, an
advisor for HACCP and SSOP in meat grinding
operations, recommended several safety improvements
to the general meat grinder design (Fuller, 2013). If
dropped, the auger (sometimes referred to as the worm)
can crack internally with no signs of damage. The
torque produced by grinding exacerbates the damage,
and when the auger finally breaks metal contaminates
the meat. The microwave detector design should be
placed after the auger so that detection of metal is
possible. Additionally it would be an interesting addition
to the plant design to be able to calibrate the microwave
detection to detect the cracks in the auger during the
SSOP. This additional calibration would be able to
compare the structural integrity of the grinder
components over time, giving the plant an idea of when
to replace the auger before it cracks and contaminates
the product.
6.3.2 MECHANISM OF OPERATION FOR
MICROWAVE DETECTION OF FOREIGN BODIES
Our team’s pilot facility includes a microwave detection
technology similar to that of Food Radar Systems AB
(Reimers, 2012). Though their design’s particular
application is in the baby food industry, their general
design and process flow can certainly be applied to meat
processing. The system consists of four parts: (1)
operator panel; (2) rejecter valve unit; (3) buffer pipe;
and (4) sensor unit (shown in Figure 6.3.3a). This
system is designed for clean-in-place (CIP) applications,
and so all system components or housed in stainless steel
cabinets with a classification of IP67 classified or
higher. IP67 is an IP code which relates to the Ingress
Protection Rating (often referred to as the International
Protection Rating) which classifies and rates the degree
of protection provided against intrusion (such as body
parts, accidental contact, dust, water, etc.). The sensor
has no moving parts, and the rejection unit is European
Hygienic Engineering & Design Group certified. As is
important in the accuracy of microwave detection, the
15
operator of the front panel should distinguish whether
the food product is “smooth” or “particulate.” In the case
of meat processing, the user should choose “smooth.”
The operator panel provides statistics on rejects and
production time product flow background noise, which
are all important characteristics in detection
troubleshooting. When a foreign body is detected, the
signal crosses the threshold and the object is rejected
(Figure 6.3.3b). The sensor head, constructed of acid
resistant stainless steel pipe, transmits and receives
microwaves. As discussed earlier, the sensor measures
the dielectric properties of the food flow, detecting and
rejecting any material which deviates from the normal
dielectric properties. The system is carefully
programmed so that a signal received leads to the
properly timed ejection of little more than the foreign
body. The system monitors all functions and, should any
bodies be detected it will log the detection and alert the
operator.
6.3.3 PARAMETERS OF DESIGN FOR MICROWAVE
DETECTION
As the microwave detection system was designed for
baby food it is important to consider its limitations, and
the challenges of adapting it to ground beef. Ground beef
is a solid, whereas baby food is liquid, this would
present challenges as to the transportation of the beef
through the system. If there was not enough pressure and
the meat may not move through the system, too much
and the added pressure could negatively affect the
quality of the meat. Thus it is important to consider two
main parameters pipe diameter and pump choice. To
utilize a microwave detection system, a proper pumping
system must be selected to transport the meat while
maintaining. Marlen International, a leading provider in
food processing equipment, offers a pumping system,
the Opti 280 ©, specifically for ground meat and other
cold stiff products (Marlen, 2013). The system depends
on a positive displacement piston pump under 500 psi to
transport the food material. The system adheres to CIP
standard, including vacuumizing chamber reduces air
content in the food for greater consistency in food safety.
Additionally, the system the pipings are easily accessible
and cleanable, and the hoppers and sleeves are all
conveniently disassemblable for easy sanitation.
Furthermore we would want to optimize the pipe
diameter to have a maximum flow rate while considering
the effective distance that the detection act across, and
an ideal pressure setting to maintain texture and moisture
quality.
Figure 6.3.3a
(1) Operator panel; (2) Sensor unit; (3) Rejection unit;
(4) Buffer pipe. (Reimers, 2012)
Figure 6.3.3b
Program displaying the threshold and detection, which
will result in foreign body removal. (Reimers, 2012)
6.4 AN ALTERNATIVE DETECTION METHOD-
MICROWAVE AND ULTRASOUND
In US patent number 3,910,124A, microwave
technology is coupled with the transmission of ultrasonic
waves to detect physical adulteration (Figure 6.4)
(Halsey, 1971). The different energy sources
complement each other to improve the resolution of the
detection as ultrasonic detection is sensitive to laminar
conditions and microwave is sensitive to changes in
density. Furthermore, ultrasonic can penetrate metal
containers while microwave can penetrate and
nonmetallic containment. In analyzing this patent it may
be of interest to utilize this dual approach in a ground
beef processing system to improve the resolution of a
detection design.
16
Figure 6.4
Dual detection of foreign bodies using microwave and
ultrasound. (Halsey, 1971)
7. CONCLUSION
Ground beef is a product that in recent year has had an
alarming increase in product adulteration, namely in
regard to physical contamination. This trend has pushed
science to develop novel techniques to address such
issues. Two such technological innovations to detect
foreign bodies, microwave and ultrasound devices, were
discussed. Current processing methodologies have the
potential to benefit from integrating these innovations
into a meat operation to ensure that food safety is
optimally conducted. In establishing a pilot plant design,
it is possible to outline how and where new detection
technology can apply to such contexts. With the
inclusion of specification requirements and further
design developments it is possible to maximize the food
safety potential of a given plant. Although these
technologies offer great gains in the field of food safety
engineering, emerging contaminant removal mechanism
will build on this foundation such that contaminant can
be effectively removed while minimizing product loss
due to defect levels. As research and development of
novel food safety technology continues to push the
limitations of this ever growing field, it is promising to
see that these new techniques have a great potential to be
applied and improve processing operations.
8. WORKS CITED
Arvanitoyannis, I. S. 2004. Detecting Foreign Bodies in Food. International Journal of Food Science & Technology
39(9):1005-1006.
Basir, O.A., B. Zhao, G.S. Mittal. 2004. Chapter 12: Ultrasound. In Detecting Foreign Bodies in Food, 204-223.
Cambridge, England.: Woodhead Publishing Limited.
CDC. (2003, May 9). Nicotine Poisoning After Ingestion of Ground Beef. Retrieved from Center for Diesease Control:
http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5218a3.htm
Cho, B. K., and J. M. K. Irudayaraj. 2003. Foreign Object and Internal Disorder Detection in Food Materials Using
Noncontact Ultrasound Imaging. Journal of Food Science, 68(3): 967-74. Available at:
http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2621.2003.tb08272.x/pdf. Accessed: Nov 30, 2013
Correia, L.R., G.S. Mittal, O.A. Basir. 2008. Ultrasonic detection of bone fragment in mechanically deboned chicken
breasts. Innovative Food Science & Emerging Technologies, 9(1): 109-115. Available at:
http://www.sciencedirect.com/science/article/pii/S146685640700077X. Accessed: Nov 30, 2013.
Flynn, D. (2009, September 14). Ten Most Meaningful Outbreaks. Retrieved from Food Safety News:
http://www.foodsafetynews.com/2009/09/ten-of-the-most-meaningful-food-borne-illness-outbreaks-picked-out-of-so-
many/#.Upew28SshcY
Fuller, C. 2013. Meat Processing Advising. D. Stanger, ed. Montreal.
Graves, M., A. Smith, and B. Batchelor. 1998. Approaches to foreign body detection in foods. Trends in Food Science &
Technology 9(1):21-27.
Halsey, G. H. 1971. Non-destructive testing procedures. US US3910124 A.
Hess, C. W. 1987. Rotary meat grinder with bone chip removal hub. USA 4,699,325.
17
Jayasooriya, S. D., B. R. Bhandari, P. Torley, B. R. D'Arcy. 2004. Effect of High Power Ultrasound Waves on Properties
of Meat: A Review." International Journal of Food Properties 7(2): 301-19. Available at:
http://www.tandfonline.com/doi/full/10.1081/JFP-120030039. Accessed: Nov 30, 2013
Junan. 2013 Junan County Linda Tools Co., Ltd. Available at: http://linda-tools.en.alibaba.com/product/475267251-
212335105/Factory_high_quality_electric_meat_mincer_22_.html.
Keener, K. 2007. SSOP and GMP Practices and Programs. West Lafayette, IN.: Purdue University. Available at:
http://www.extension.purdue.edu/extmedia/FS/FS-21-W.pdf. Accessed on November 30, 2013.
Marlen. 2013. Opti 280 Vacuum Pump. Marlen International. Available at:
http://www.marlen.com/equipment/pumping/opti-280/.
Reimers, M. 2012. The Food Radar. In European Dairy Magazine. Gothenburg, Sweden.
Rastogi, Navin K. 2011. Opportunities and Challenges in Application of Ultrasound in Food Processing. Critical Reviews
in Food Science and Nutrition, 51(8): 705-22. Available at:
http://www.tandfonline.com/doi/full/10.1080/10408391003770583. Accessed: Nov 30, 2013
Salvade, A., M. Pastorino, R. Monleone, A. Randazzo, T. Bartesaghi, G. Bozza, and S. Poretti. 2008. Microwave imaging
of foreign bodies inside wood trunks. In Imaging Systems and Techniques, 2008. IST 2008. IEEE International
Workshop on.
Schlager, D., A.B. Sanders, D. Wiggins, W. Boren. 1991. Ultrasound for the detection of foreign bodies. Annals of
Emergency Medicine, 20(2): 189-191. Available at:
http://www.sciencedirect.com/science/article/pii/S019606440581220X. Accessed: Nov 30, 2013
USDA. 1994. Generic HACCP Model for FreshGround Beef. F. S. a. I. Service, ed: United States Department of
Agriculture.
USDA. 2013. Recall Notification Report 057-2013. United States Department of Agriculture, Food Saftey and Inspection
Service. Available at: http://www.fsis.usda.gov/wps/portal/fsis/topics/recalls-and-public-health-alerts/recall-case-
archive/archive/2013/rnr-057-2013. Accessed Nov 30, 2013
Young, J. S. (2006, Febuary 1). More Metal Found in Food: Giant Ground Beef Tainted. Retrieved from International
Food Safety Network: http://www.foodsafety.ksu.edu/en/news-details.php?a=4&c=30&sc=276&id=57253
18
9. APPENDIX
Table 4.2.5: The Effects of High Power Ultrasound on Properties of Meat
Muscle
component
Frequen
cy (kHz)
Intensity
(W/cm2)
a
Power (W)b
Duration
(s)
Ultrasonic
apparatus Comments
Extracted
collagen
macromolecules
9 50b 600–26,
400
Raytheon
Magnetostr
iction
Generator
Fragmentation of long
rodlike collagen
macromolecules in to
shorter pieces
Beef and rat
skeletal muscle
homogenates
and
mitochondrial
suspensions
N/A N/A 2 × 30 Branson
Sonifier
Disruption of
lysosomes & increase
in enzymic activity
Meat 19 1.5–3a 60–1,500 N/A Significant
tenderization of meat
Broiler breast
muscle
40 2, 400b 900 Ultrasonic
bath (NEY
proSONIK
™)2
Significant reduction
of shear force of the
treated muscles
Beef sirloin
steak
40 2a 7,200 N/A Significant reduction
of intramuscular
collagen and the
tenderness
Semitendinosus
muscle
25.9 N/A 120–960 Water bath
(SWEN
SONIC)
20.5 × 20 ×
20 cm
Significant decrease in
shear force at 2 and 4
min and increased
shear force at 8 min
Lamb skeletal
muscle
N/A 57, 62b 10–180 Branson
Sonifier
model
250/450
Enhanced proteolytic
degradation increased
appearance of 30 kDa
region band, an
indicator for
tenderization
Beef
Semitendinosus
muscle and
Biceps femoris
20 1.55 a 480, 960,
1,440
Magnapak
T-series
transducer
tank
No significant effect
on shear force or long-
term inhibition of
microbial growth
19
muscle
Beef Pectoralis
muscle
20 22a 300, 600 Tekmar®
Sonis
Disrupter
Ultrasound exposure
had very little effect
on aging, sensory,
shear, and cooking
properties
Beef
Longissimus(LT
L),Semitendinos
us andBiceps
femoris muscles
30–47 0.29–0.62a 0–5,400 1.Hilsonic
(FM 200)
2. Kerry
KS 571 3.
Ultrawave
U500
No significant
increase in proteolytic
degradation, and
reduction in shear
force values
Beef
Longissimus(LT
L),Semimembra
nosusmuscle
20 62a 15 Ultrasound
probe
(Heat
systems
model XL
2020)
No significant
improvement in
proteolysis and
tenderness
Pancreas tissue 19.5 3.3a 300–600 N/A Significant increase in
extraction of insulin
Calf abomasum 19.2 3.34a 2700 N/A Optimum
technological
parameters for
extraction of
chymosin and the
properties of
extraction medium
were achieved
Calf abomasum 20 20–41a 4800 Tekmar
Sonic
Disrupter
TK 1000
Significant increase in
chymosin (rennin)
extraction
Cured ham rolls N/A N/A 900–7,200 Cole-
Palmer
Ultrasonic
Cleaner
Model:
8845-3
Changes in muscle
microstructure and
increase in breaking
strength
Cooked ham-
horse meat
22 5,000b 4 × 600 N/A Changes in muscle
micro structure and as
a result increased
tenderness, juiciness
20
Restructured
beef rolls
15 N/A 4 × 300 Branson
ultrasonic
horn
attached to
a tumbler
Muscle fibre
disruption, superior
breaking strength and
cooking yield
Broiler
drumstick skin
47 200b 900, 1,800 Bransonic
Ultrasonics
cleaning
bath model
5200R
No significant effects
of ultrasound on the
aerobic plate count
(ABC) during storage
Broiler skin 20 N/A 1,800 N/A Salmonellae attached
to broiler skin were
reduced significantly
Beef
Semitendinosus
and Biceps
femorismuscle
20 1.55a 1,800 Magnapak
T-series
transducer
tank
Immediate impact on
reducing meat micro-
organism numbers but
failed to inhibit long-
term growth
