1. Why use
noncontact infrared thermometers?
Noncontact infrared (IR) thermometers use
infrared technology to quickly and conveniently measure the surface
temperature of objects. They provide fast
temperature readings without physically touching the object. You simply aim,
pull the trigger and read the temperature on the LCD display.
Lightweight, compact, and easy-to-use, IR
thermometers can safely measure hot, hazardous, or hard-to-reach surfaces
without contaminating or damaging the object. Also, infrared thermometers
can provide several readings per second,
as compared to contact methods where each measurement can take several
minutes.
2. How does IR
work?
IR thermometers capture
the invisible infrared energy naturally emitted from all
objects. Infrared
radiation is part of the electromagnetic spectrum which
includes radio waves,
microwaves, visible light, ultraviolet, gamma, and X-rays.
3. About Emissivity
 This infrared
"invisible heat" of an object is transferred in three ways: Reflected,
Transmitted, and Emitted. Reflected energy is not particularly related to
the temperature of the target object, and transmitted heat is related to the
both the internal temperature of the target object and the temperature of
the "transmitted to" object.
The only type of energy
that can be used to tell that actual surface temperature of the object is
Emitted energy.
When IR thermometers are
used to measure surface temperature they can potentially sense all three
kinds of energy, therefore all thermometers have to be adjusted to read
Emitted energy only.
Measuring errors are often caused by IR energy being reflected by
light sources.
Some IR thermometers
allow you to change the Emissivity in the unit. The value of Emissivity
for various materials can be looked up in published Emissivity table.
Other units have a fixed,
pre-set Emissivity of 0.95, which is the Emissivity value for most organic
materials and painted or oxidized surfaces. If you are using a thermometer
with a fixed Emissivity to measure the surface temperature of a
shiny object you can
compensate by covering the surface to be measured with masking tape
or flat black paint. Allow time for the tape or paint to reach the
same temperature as the
material underneath. Measure the temperature of the taped or painted
surface. That is the true temperature.
Accurate Temperature
Measurement Tips
When measuring shiny
surfaces, such as aluminum and stainless steel, the reflectivity of the
surface will skew the reading of an IR thermometer unless you accommodate
for it. Either coat surfaces such as griddles or cooking pans with a
non-stick cooking spray before you take your reading, or place a small piece
of masking tape on the metal surface and measure the taped area.
An IR thermometer can go
from kitchen to cold storage (above freezing) and still provide an accurate
reading if given time to acclimate to the new ambient temperature. It's best
to leave the unit where it will be used most often. Note: If the unit is
left in an environment below freezing, it will temporarily fail to operate
properly.
Use an IR thermometer to
read internal temperatures of liquids, such as soups or sauces, simply by
stirring the liquid and then reading the surface temperature. Keep the
thermometer away from steam to avoid condensation on the lens, which will
skew your reading.
Factors That Affect the Accuracy
of Readings
 |
1) Field-of-view.
Make sure that the target is larger than the spot size the unit is
measuring. The smaller the target, the closer you should be to it. When
accuracy is critical make sure that the target is at least twice as
large as the spot size.
|
 |
2) Distance to
spot ratio. The optical system of an infrared thermometer
collects the infrared energy from a circular measurement spot and
focuses it on the detector. Optical resolution is defined by the ratio
of the distance from instrument to the object compared to the size of
the spot being measured (D:S ratio). The larger the ratio number the
better the instrument's resolution, and the smaller the the spot size
that can be measured. The laser sighting included in some instruments
only helps to aim at the measured spot.
A recent innovation in infrared optics is
the addition of a Close Focus feature, which provides accurate
measurement of small target areas without including unwanted background
temperatures. |
Monitoring Food
Receiving. Quality
assurance begins at the receiving dock. When a delivery of fresh or frozen
food arrives, use your All QA Products IR thermometer to check that the
products, shipping crates, and internal temperature of the delivery truck
are all at the right temperatures.
Storage. Once
received, verify that frozen and chilled foods are stored at or below 40°F
(4.4°C) to assure freshness and quality. In supermarkets where product may
be stacked unevenly or too high in display cases and freezers, check to find
warm spots or uneven cooling. Also, you can quickly and frequently monitor
proper temperatures of all items stored in walk-ins.
Cooking. Exact
temperatures become vital to preventing food-borne illness. To avoid
bacteria growth, many foods must be cooked to a specific temperature. An All
QA Products thermometer instantly confirms that your surface temperatures
are within safe parameters. In order to confirm internal temperatures, you
can use All QA Products thermometer that feature an internal probe.
Holding and Serving.
Food products that are ready to be served or sold and are located in holding
or serving areas must be kept out of the Temperature Danger Zone which is 40
to 140°F or 4.4 to 60°C.
-
Cold Holding
With your IR thermometer, quickly verify that the temperature of products
held in open-top refrigeration units, such as fresh meat or fish displays,
cold buffets, or preparation units, do not exceed 40°F (4.4°C), as
mandated by the FDA's 2000 Food Code.
-
Hot Holding
Warm prepared foods that are kept in steam tables, warming ovens,
and other heated serving and holding areas should be carefully monitored
to
remain at 140°F (60°C) or above. You can use your IR thermometer to check
the
internal temperatures of soups, gravies, and other liquid foods by
agitating them
before reading.
-
Cooling
Improper cooling is the number one cause of food borne illness. After food
has been cooked and served, use your All QA Products thermometer to
confirm that leftovers are taken down to an appropriate temperature—from
above 140 to below 70°F (60 to 21.1°C) within two hours, and then down to
below 40°F (4.4°C) within another four hours.
-
Reheating
The last
important temperature-related checkpoint is reheating. Your IR thermometer
can confirm that foods are being reheated to at least 165°F (73.9°C) to
destroy any bacteria caused by improper cooling or storage techniques.
Monitoring Equipment
You can use your
noncontact thermometer to check more than just the temperature of food. You
can also evaluate the performance of your equipment and machinery.
-
Detect hot spots or leaks by taking sample spot readings
of freezers, walk-in coolers, refrigeration lines, compressor motors,
electrical, and HVAC equipment.
-
Safely check the temperature and performance of ovens,
ranges, rotisseries, deep
fryers and dishwashers.
-
Check clean dishes immediately after washing to ensure
that high enough
temperature levels were achieved in the dishwasher for sanitation
purposes.
Other Uses in
Gourmet/Specialty Cooking
Many specialty food
recipes call for very specific preparation temperatures. For example, sugar
used in meringues and icings relaxes to the softball stage at 220°F (104°C);
at 320°F (160°C) caramel reaches the stage for flavoring and decorating, and
at 350°F (177°C) it darkens. By using an IR thermometer you can instantly
check these temperatures and avoid the mess of using a contact thermometer.
Experience
notwithstanding, it is often difficult to know when cooking surfaces have
reached the proper temperatures. For example, a common way to test whether a
griddle is "pancake ready" is to see if a drop of water skittles across its
surface. But water does this at a wide temperature range—roughly between
320° to 440°F (160° to 227°C)—whereas pancakes griddle best between 350° and
370°F (177° and 188°C) and meat, on the other hand, sears best at about
450°F (232°C). By instantly knowing these temperatures you can avoid the
guesswork and ensure food is cooked perfectly.
All QA Products
noncontact IR thermometers can help you monitor everything from food to
fixtures with one hand-held instrument. Check out our
comparison of different instruments. |
FAX Order Line
1-704-829-6602
Mt. Holly,
North Carolina 28120 USA 
