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FAQ's Associated with the Use
and Interpretation
of Sani-Check Test Kits and Dipslides
Do you have microbiological
test kits or dipslides to detect algae?
No, our test kits and dipslides only detect bacteria, yeast, and mold. Algae
are very slow growing organisms and require very complex growth
media and incubation conditions.
Other than the expiration date,
how can I tell if a dipslide is still acceptable to use for testing?
If the agar on the dipslide has not dried out and still remains
intact, it will usually be acceptable to use.
Is a dipslide still acceptable
to use for testing if it has not expired but the agar has dried
out?
No, the dipslide is not acceptable to use.
The test kit instructions specify
an incubation temperature range.
What is the actual temperature that is required for incubation?
If you have an incubator, store the dipslides at approximately 30°C. If an incubator is not available, incubate the
dipslides
at room temperature (22-24°C
or 72-75°F)
by storing them in a warm location. If you are incubating the
dipslides
at room temperature, an extended incubation time is recommended
(see the following FAQ).
The dipslide instructions specify an
incubation period of 24-36 hours.
How long should I incubate the dipslides?
If you are incubating the dipslides at room temperature, we recommend
an incubation period of 36 hours. If you are incubating at 30°C,
the dipslides can be read after 24 hours.
Do the dipslides need to be incubated in
light or dark conditions?
Either environment is acceptable because the presence of light
has no impact on the dipslide itself.
I incubated my dipslides longer than 36
hours. Is this a problem?
No, it is acceptable to incubate the dipslides for 48 hours or more. However,
keep in mind that the longer the dipslides are left to incubate, the
larger the colonies may appear on the agar surface. When large
numbers of microorganisms are present, an extended incubation period
may result in dipslides that are difficult to interpret.
I have larger dots on my dipslide.
Does this mean I have more microorganisms?
No, the dot or colony size on a dipslide is independent of the number
of microorganisms. If lower numbers of microorganisms
are present, the colonies may grow in size on the dipslide but this does not always
occur.
Some of my colonies on the dipslide are not red.
What does this mean?
The colonies turn red on the dipslide because of the reduction of an indicator
dye. This dye is added to the dipslide in order to aid the viewing of the colonies
against the agar surface.
Certain bacteria do not always reduce this dye which would
result in an occasional colorless colony.
Are all colonies on the fungal side
of a BF dipslide considered to be yeast or mold? Are all colonies
on the bacterial side considered to be bacteria?
Specific agents are present in the fungal agar to inhibit the growth
of bacteria. However, some bacteria are resistant to the inhibitors
and may still appear on the fungal agar. The same is true for the
bacterial agar. Certain inhibitors are present to deter the growth
of fungi but some may still appear on the bacterial agar. If you
are unsure of the interpretation of a dipslide, send us the item in
question and we can determine what types of microorganisms are actually
present. At Biosan Laboratories, we offer free technical service
with all of our microbiological test kits.
My dipslide surface turned red or pink
almost immediately. Do I have lots of bacteria?
No, this is most likely a chemical reaction. The dye that is added
to the media on the dipslide in order to color the colonies red, reacts when the
sugar in the media is broken down. This reaction may be caused by
bacteria or even by certain chemicals. If the color change is due to a chemical reaction, it should
happen within the first 15-30 minutes. Also, no colonies would be
visible on the dipslide surface within that time period.
How do I dispose of a used test strip
or dipslide?
We suggest to soak dipslides and test strips in a 5% bleach solution for 30 minutes
before disposal. This solution can be poured directly into the dipslide
vial or the test strip incubation pouch. For other suggestions,
contact our Technical Service Department at (800) 253-6800.
What does 103, 104,
105 etc. mean?
The superscript number specifies the power of 10. If a dipslide is
interpreted to contain 103 microorganisms/mL, this means
that there are 10 x 10 x 10 or 1000 microorganisms present. If 104
microorganisms are present, this corresponds to 10,000 microorganisms
and so on.
How much bacteria is an acceptable
level for cooling water or metalworking fluid?
Although you should determine what is an acceptable level of bacteria
for your unique system, a general guide would be 105-106
CFU/ml for cooling water and 106-107 CFU/ml
for metalworking fluid.
Do you have microbiological
test kits or dipslides to detect anaerobic bacteria?
Our Sani-Check SRB Test Kit will detect sulfate-reducing bacteria
which are also anaerobic. However, we do not have a test kit or a
dipslide that
will detect other types of anaerobic bacteria.
Do the Sani-Check Dipslides identify specific microorganisms such as Legionella or
other pathogens?
Not necessarily. The identification of specific microorganisms
is more complex and usually performed only within a microbiology
laboratory.
Biosan Laboratories can analyze your samples for a variety of microorganisms
including Legionella and Mycobacterium, as well
as foodborne pathogens such as Listeria.
For additional information, please contact
our Technical Service Department at (800) 253-6800.
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Biosan Laboratories, Inc.
1950 Tobsal Court, Warren, MI 48091-1351
Phone (586) 755-8970 / (800) 253-6800
Fax (586) 755-8978 e-mail lesley@biosan.com
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