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physical properties of the contaminants. For instance, chemical reactions can be
used for determination of lignin characteristics and enzymatic reactions.
5. Confirm. In many cases, no single method is 100 percent guaranteed to
complete an investigation and identification. Further testing may be required to
validate the findings or disprove them. For example, analysis by atomic absorption spectroscopy or other elemental analysis techniques reveals different types
of metals. Examination of the combustion qualities of a sample can be used to
find and quantitate foreign ferrous metal particles. Protein quantitative tests can
confirm the presence of animal matter.
6. Compare. Building a reference library is necessary for a forensics laboratory. Identification relies on the availability of good reference library texts and
official methods containing authentic reference materials as well as spectral databases to obtain definitive confirmation of the contaminants.
7. Evaluate the root cause. Whether a contaminant went through a specific
processing step and was introduced into the product prior to or after packaging,
potential sources could be uncovered through a prudent review of all test results
and existing factors. If a piece of glass was confirmed, the following question will
be raised: Is it more likely to be from a lightbulb, bottle, window glass, or drinking glass? This evaluation can be done to obtain more detailed information and
evidence from the contaminant’s size, shape, mass, and characteristic features,
especially compared with authentic reference materials. Any reference samples
provided by clients are helpful to address the root cause.
8. Prepare a comprehensive report. After the investigation and identification
are complete, a comprehensive report should be prepared, containing a summary of the project goals, sample information, test methods, imaging evidence,
findings, evaluations, and/or suggestions.
A considerable variety of contaminants are possible in food that can render
a food undesirable as a potential health hazard. Food companies rely heavily on
a wide range of methods to minimize contamination and to detect it when it
occurs. Investigation, identification, and remediation of food contaminants are
powerful means to proactively avoid safety threats to consumer health and major losses to a company’s reputation and finances.
Food safety investigation and hazard prevention are complex and challenging. A strong, well-networked investigatory team is essential. A forensics team
equipped with a wide range of knowledge, skills, and experience is crucial. These
investigators must have good judgment when adverse incidents occur and be
able to determine the precise characteristics and features of the physical contaminants. Because each incident varies, the capability to develop relevant techniques
for a complex investigation is challenging and essential to the forensic laboratory. n
Samuel S. Liu, Ph.D., is a science officer and chief entomologist in the food forensics department of Certified
Wireless Sensor System
Swift Sensors Inc. is providing a cloud-based wireless sensor system for industrial
and commercial applications. This system
fundamentally replaces manual processes
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Swift Sensor technology monitors temperature, humidity, vibration, motion, activity,
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Swift Sensors, 866.308.1340
Synthetic Long-Life, High-
Klüber Lubrication has recently introduced Klüberfood NH1 74-401, designed
for incidental food contact in food and
pharmaceutical processing. The grease
combines the high performance and load-carrying capacity of a synthetic base oil
with the versatility of an innovative urea
thickener. This high-temperature grease
can be used in a variety of food processing
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bearings in ovens and proofers, conveyors
and motor bearings, and roller bearings in
packaging and labeling machines.
Klüber Lubrication, 603.647.4104
Certified Listeria Test
Romer Labs has introduced a new
pathogen testing system: RapidChek®
Listeria monocytogenes. In its Performance
Tested Methods program, AOAC has certified the testing system for detecting the
pathogen on environmental surfaces and
ready-to-eat foods, including hot dogs,
frozen breaded chicken, frozen cooked
shrimp, cured ham, and ice cream.
Romer Labs, 302.781.6400