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The following information is provided
courtesy of The Catering Equipment Suppliers Association.
Understanding Refrigeration
A fridge is an
insulated cabinet with an electric pump or a compressor which
moves a refrigerant liquid around the cooling bars. When the
door is opened, the cold air falls out to be replaced by warm
air in the kitchen, which triggers the pump to circulate the
refrigerant liquid and cool down the internal temperature and
keep the food safe.
Domestic
fridges and commercial fridge look similar, but are not. With a
domestic fridge, the power of the compressor is designed around
the few number of times a domestic fridge door is opened during
the day. A quite modestly-powered compressor will be able to
cope with the heat loss without food safety risks. The
construction of both the cabinet and the motor is only robust
enough for light domestic use, so used in a commercial
environment, not only do they pose a food safety hazard, they
need replacing far more often than commercial fridges, so are
not even cost effective.
With a
commercial specification fridge in a busy working kitchen, the
door is going to be opened very regularly and probably be
exposed to a far hotter kitchen. The compressor needs to be
powerful enough to rapidly pull down the internal fridge
temperature to replace heat loss.
Most
commercial fridges also incorporate fans which evenly spread the
cool air through the cabinet, a feature domestic fridges do not
have. Commercial fridges are better insulated, designed for easy
cleaning and some are able to electronically record temperatures
which can be used as proof of due diligence in food safety
procedures should a food poising claim be made. As well as
freestanding fridges it is also possible to get walk-in fridges
which can be built to fit a specific kitchen area.
Freezers
Commercial
freezers share all the high specification features of commercial
fridges and should always be used for the same performance, food
safety and cost efficiency reasons.
Blast chillers
and freezers
These are
refrigeration cabinets which use fiercely-driven cold air to
rapidly pull-down the temperature of hot food so it can be
safely stored either in chilled or frozen form for future
re-heating. Allowing foods to cool without refrigeration can be
extremely dangerous as it will allow harmful bacteria to develop
during the long cooling process.
Cooling hot foods in a fridge already containing
chilled food is also very dangerous as it will raise the
temperature of all the food in the fridge and pose a food safety
risk. Any kitchen which wants to have pre-cooked, chilled food
as a major part of the provision must have blast refrigeration.
How to choose the right
fridge or freezer
Talk to a
manufacturer who will look at the type of operation you are
running, the mix of fresh, chilled and frozen food you serve,
the volume of meals you are preparing. This will identify the
capacity of unit you need and the power of it. It is the same
with ice cube needs – let someone else do the specification
sums. The advice will be free.
Look After It!
The outward
construction of a piece of refrigeration equipment appear
simple, but while operation seem trouble free, miss-use can lead
to under-performance and add
unnecessary
cost to maintenance bills as much as any other equipment in the
kitchen.
Overloading
shelves and above marked levels in a refrigeration cabinet will
affect performance with the potential to interrupt the cold
airflow. Commercial fridges should always be fitted with
circulatory fans, but if food is pushed up against the fan, the
cold air is not going to circulate properly. This is not just a
food safety issue, but can cause the fridge fan to run faster
than it needs to leading to the possibility or replacement
earlier than should be.
The location
of any refrigeration equipment is important. Fridges designed
for use in temperate climates such as the UK and most of Europe
work on a maximum ambient temperature of 28 deg C. That means
that while the atmosphere in the kitchen will always fluctuate
according to the cooking going on and the outside temperature,
the thermometer does not rise above 28 deg C. Some units are
designed to operate in ambient temperatures of up to 43 deg C,
check the specifications for each model.
If it does,
then the compressor in the fridge, which is the motor that pumps
the cooling fluid around the cooling bars, will be overworked.
This could lead to premature burn out of the compressor and have
a food safety risk. Where ever practical, refrigeration units
should be sited away from direct cooking heat.
It is good
working practice to regularly check the temperature of the
fridge using a digital thermometer. A service engineer will do
this as routine, but if the fridge is beginning to lose power,
then the engineer will need to be called out quickly to prevent
food from the risk of contamination. Many commercial fridges
have digital temperature displays, but it is still useful to
perform this occasional check.
As part of
the regular thorough cleaning of the kitchen, include using an
appropriate attachment to a vacuum cleaner to clean the area
around the compressor if it is accessible. This will prevent
excess dust and fluff from getting inside the compressor and
being a damage risk.
Because of
the constant opening and closing of fridge doors, door seals
will wear out. A damaged door seal will force the compressor to
work harder than its needs to, which apart from anything else
will increase energy use. The service engineer will check them
on a routine inspection, but it should be part of a fridge
clean-down to inspect the seals for any sign of damage. It will
also prolong the life of door seals if staff are encouraged to
close doors and not slam them shut.
In brief
Do
Check and
clean door seals weekly
Clean up spillages immediately
Visually check compressor fins and vents monthly
Defrost freezers to manufacturers’ instructions
Check working temperature monthly
Don’t
Overload the
fridge
Allow fans to be obstructed
Leave the door open
Put hot food in
Slam doors
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