COMPACT DRY™ TC

Cat. no. 54081 Compact Dry™ TC, 60x75mm Tray with 10x60mm Well 240 trays/box

INTENDED USE
Hardy Diagnostics Compact Dry™ TC is a ready-to-use test method recommended for the determination of total
aerobic bacterial counts in raw materials, finished products, or on environmental surfaces pertaining to food and related
industries.

This product is not intended to be used for the diagnosis of human disease.

SUMMARY
Microbiological testing is a common practice in food and related industries to ensure product quality and a high level of
environmental control. Foods, beverages, and similar finished products are usually not sterile. However, in order to
ensure they are safe for human consumption, maximum cell load numbers for the finished product, as well as for raw
materials used to produce them, have been established. Procedures for determining aerobic plate count (APC) of foods
were developed by the Association of Official Analytical Communities (AOAC)(5) and the American Public Health
Association (APHA).(2-4) Conventional plate count methods for examining frozen, chilled, precooked, or prepared
foods and the automated spiral plate count method for the examination of foods and cosmetics are outlined in FDA
Bacterial Analytical Manual.(1)

Compact Dry™ TC is a ready-to-use chromogenic medium for performing total viable aerobic bacterial counts that
contains dehydrated culture media and a cold water-soluble gelling agent in a non-woven cloth matrix. The medium is
instantly hydrated when inoculated with a sample, and capillary action diffuses the sample evenly over the matrix to
form a gel within seconds. Colonies grown on Compact Dry™ TC turn red due to the redox indicator, tri-
phenlytetrazolium chloride (TTC).

Compact Dry™ TC is comparable to other dry film test methods and to the spiral plate method.(6) Compact Dry™ TC
is AOAC validated (AOAC no. 010404) and the ready-to-use trays save space and greatly reduce the time needed to
perform microbiological testing. Compared to other commenly used culture systems, Compact Dry™ has a longer shelf
life, can be stored at room temperature, does not require manual sample spreading, is rigid, stackable and easy to label,
and allows for direct colony picking for further subculture.

FORMULA
Compact Dry™ TC contains dehydrated culture media, a gelling agent, and the redox dye, 2,3,5-triphenyl tetrazolium
chloride (TTC), to facilitate differentiation of colony growth.

Final pH 7.0 +/- 0.2 at 25°C

STORAGE AND SHELF LIFE
Storage: Upon receipt, store at 1-30ºC. away from direct light. Media should not be used if there are any signs of
deterioration, contamination, or if the expiration date has passed. Product is light and temperature sensitive; protect
from light, excessive heat, moisture, and freezing. If foil pouch is opened and not all plates are used, return remaining
plates to pouch and reseal until next use. Opened packages should be used as soon as possible.

The expiration date on the product label applies to the product in its intact packaging when stored as directed. The
product may be used and tested up to the expiration date on the product label and incubated for the recommended
quality control incubation times as stated below.

Refer to the document "Storage" for more information.

PRECAUTIONS
This product may contain components of animal origin. Certified knowledge of the origin and/or sanitary state of the
animals does not guarantee the absence of transmissible pathogenic agents. Therefore, it is recommended that these
products be treated as potentially infectious, and handle observing the usual universal blood precautions. Do not ingest,
inhale, or allow to come into contact with skin.

This product is for laboratory use only. It is to be used only by adequately trained and qualified laboratory personnel.
Observe approved biohazard precautions and aseptic techniques. All laboratory specimens should be considered
infectious and handled according to "standard precautions." Refer to the document "Guidelines for Isolation
Precautions" from the Centers for Disease Control and Prevention.

For additional information regarding specific precautions for the prevention of the transmission of all infectious agents
from laboratory instruments and materials, and for recommendations for the management of exposure to infectious
disease, refer to CLSI document M29: Protection of Laboratory Workers from Occupationally Acquired Infections.

Sterilize all biohazard waste before disposal.

Refer to the document "Precautions When Using Media" for more information.

PROCEDURE
Prior to Use: Refer to listed references for appropriate methods of collection, preparation, and dilution of samples under
investigation. (1-5)

For environmental samples or to test uneven surfaces of equipment, swab surface of test area with EnviroTrans™ (e.g.
Cat. no. SRK05 or SRK35).

For raw material and food testing, prepare and dilute samples using an appropriate diluent such as Dilu-Lok™ II (e.g.
Cat. no. D590 or D599).

General Dilution Guidelines:

For Making 1:10 Serial Dilutions

1. Using a sterile pipet or scoop, aliquot 10ml or 10gm of test sample to a 90ml pre-filled Dilu-Lok II™ dilution vial to
yield a 1:10 dilution. Mix thoroughly.

2. From the 1:10 dilution vial in step 1, use a fresh sterile pipet and aliquot 10ml from this dilution vial into a second
90ml pre-filled Dilu-Lok II™ vial to yield a 1:100 dilution. Mix thoroughly.

3. Continue aliquoting 10ml dilutions into 90ml pre-filled Dilu-Lok II™ vials until the desired concentration of test
sample is achieved. Each subsequent dilution increases by a factor of 10. A separate sterile pipet should be used with
each dilution. Each subsequent dilution increases by a factor of 10. A separate sterile pipet should be used with each
dilution.
For Making 1:100 Serial Dilutions
1. Using a sterile pipet or scoop, aliquot 1ml or 1gm of test sample to a 99ml pre-filled Dilu-Lok II™ dilution vial to
yield a 1:100 dilution. Mix thoroughly.

2. From the 1:100 dilution vial in step 1, use a fresh sterile pipet and aliquot 1ml from this dilution vial into a second
99ml pre-filled Dilu-Lok II™ vial to yield a 1:10,000 dilution. Mix thoroughly.

3. Continue aliquoting 1ml dilutions into 99ml pre-filled Dilu-Lok II™ vials until the desired concentration is achieved.
Each subsequent dilution increases by a factor of 100. A separate sterile pipet should be used with each dilution.

Method of Use Direct Inoculation:

1. Remove the set of four trays from the foil pouch and separate each individual tray by gently bending along the
connecting edge until each tray snaps free. Alternatively, if setting up a dilution series of the same sample, trays can be
left connected to facilitate reading similar samples. Trays that are not used immediately should be resealed in the foil
pouch. Refer to the "Storage and Shelf Life" section for proper storage of unused trays.

2. Remove the lid of the tray using two fingers to hold down one end of the lid and the thumb to lift the opposite end.
Lids are easier to remove using a “peel back” method as opposed to a“pull off” method.

3. Inoculate by pipetting 1ml of sample directly to the center of a dry tray well, being careful not to touch the surface of
the matrix with the pipet tip. Once dispensed, the sample will automatically diffuse across the surface by capillary
action to form a gel; manual spreading of the inoculum is discouraged. Remember to account for the sample inoculum
when calculating the dilution series.

4. Replace the lid and label the tray with appropriate information, including the sample dilution factor.

5. Invert the tray and incubate, upside down with the medium on top, at 35-37°C for 48 hours. NOTE: Use the
appropriate temperature/timedesignation according to the legal specification of the prescribed foodanalysis regulation.

6. Count colonies using the Hardy Diagnostics Wizard™ CompactDry™ plate reader (Cat. no. CDR1) designed
exclusively for use with Compact Dry™. See the Wizard™ Compact Dry™ instruction manual. Alternatively, colonies
can be counted when illuminated from the backside of the tray to calculate CFU/ml using the Scan® 100 colony
counter (Cat. no. 435000) or comparable backlighting. If the colony count is high, use the 1cm x 1cm molded grid on
the back of the tray to assist in colony counting. Use a sheet of white paper with gridded lines to diffuse the light if the
molded grids in the tray are difficult to visualize with a light box.

Method of Use Membrane Filtration:

1. Remove the lid on a Compact Dry™ plate and pipette 1.0ml of sterile purified water into the middle of the plate to
activate the matrix just before use.

2. Using a membrane filtration set-up, filter 100-250ml of a water sample under reduced pressure through a sterile
0.45µm membrane filter.

3. Keep the set-up running and rinse the inside of the filter funnel using 20-30ml of sterile purified water. Repeat this
step two to three times to ensure all of the sample has been filtered through the membrane.

4. Remove the membrane from the funnel using sterile forceps (e.g. Cat. no. 800000) and apply it filter side up (trap
side away from the matrix) to the surface of the pre-moistened Compact Dry™ plate. Gently press the membrane onto
the surface, making sure to remove bubbles so the membrane is completely flush and centered on the matrix.

5. Replace the lid and incubate the tray right-side-up using the information outlined above.

6. Count colonies and record results as outlined above.

INTERPRETATION OF RESULTS
After incubation, read trays using the Wizard™ CompactDry™ plate reader (Cat. no. CDR1) or read colonies against a
white or illuminated background such as with the Scan® 100 colony counter (Cat. no. 435000) or comparable back
lighting.

Most colonies will be red due to reduction of TTC. Count all colonies, regardless of pigmentation, to obtain the total
aerobic count. The growth area is 20cm2. If the colony count is high, the total count can be obtained by multiplying the
average number of colonies observed in one 1cm x 1cm square grid by 20.

LIMITATIONS
During inoculation, do not touch the surface of medium and be careful to avoid any contamination by airborne
microorganisms.

During incubation, keep cap tight on plates to avoid any possible dehydration.

A dilution may be needed when the sample has a dark color.

When the sample is viscous (thick), pipetting the sample on several points on a plate or an additional dilution may be
needed for an even suspension.

When the sample contains an enzyme, it may react with the enzyme substrate in the dry sheet and affect the color.

If the nature of sample does affect the reaction of the medium, inoculate only after the factor is eliminated by means of
dilution and other techniques (e.g. samples with high viscosity, colored, reactive with chromogenic substrate, and with
a high or low pH).

It is recommended to use a stomacher and filter homogenized sample afterwards to eliminate carry over of tiny
particles of foodstuff onto the surface of the medium.

Since some microorganisms may not reduce TTC and develop red/pink color, colonies that are not necessarily a clear
red color could develop.

Counting colonies may be difficult against a dark background. For best results, count colonies using the Hardy
Diagnostics Wizard™ Compact Dry™ plate reader (Cat. no. CDR1) or with the tray held against a white or illuminated
background such as with the Scan® 100 colony counter (Cat. no. 435000).

If using a light box, molded grid lines in the tray, or colonies, may be difficult to view due to excessive brightness.
Diffuse the light using a sheet of white, gridded (1cm x 1cm) paper underneath the tray to facilitate colony counting.

Colonies are not distinguishable on trays if concentrations are above 100 CFU/ml, as high colony counts will result in
the whole surface becoming colored. The sample should be diluted to a concentration of less than 100 CFU/ml for best
use.

Some microorganisms may not reduce TTC and may fail to develop red-colored colonies. Count all colonies present,
regardless of red pigmentation.

Refer to the document "Limitations of Procedures and Warranty" for more information.

MATERIALS REQUIRED BUT NOT PROVIDED

Standard microbiological supplies and equipment such as loops, swabs such as EnviroTrans™, applicator sticks,
scoops, dilution buffers such as Dilu-Lok™ II, other culture media, Wizard™ Compact Dry™ plate reader (Cat. no.
CDR1), Scan® 100 colony counter (Cat. no. 435000), incinerators, and incubators, etc., as well as serological and
biochemical reagents, are not provided.

QUALITY CONTROL
End users can anticipate the following typical performance characteristics when testing with CompactDry™.

Incubation
Inoculation
Test Organisms Results
Method*
Time Temperature Atmosphere

Bacillus subtilis
J 48hr 35-37°C Aerobic Growth;red colonies
ATCC® 6633

Escherichia coli
J 48hr 35-37°C Aerobic Growth; red colonies
ATCC® 8739

Klebsiella pneumoniae
J 48hr 35-37°C Aerobic Growth;red colonies
ATCC® 13883

Pseudomonas aeruginosa
J 48hr 35-37°C Aerobic Growth;red colonies
ATCC® 9027

Staphylococcus aureus
J 48hr 35-37°C Aerobic Growth;red colonies
ATCC® 6538

* Refer to the document "Inoculation Procedures for Media QC" for more information.

USER QUALITY CONTROL

Check for signs of contamination and deterioration. Users of commercially prepared culture media may be required to
perform quality control testing to demonstrate growth or a positive reaction and to demonstrate inhibition or a negative
reaction (where applicable). See the following reference for more specific information. (1-5)

PHYSICAL APPEARANCE
Compact Dry™ TC should appear dry, free of particles, and light yellow in color.

Staphylococcus aureus (ATCC® 6538) and Escherichia coli

(ATCC® 8739) colonies growing on Compact Dry TC (Cat. no.
54081). Incubated aerobically for 48 hours at 35°C.

REFERENCES
1. Association of Official Analytical Communities. Official Methods of Analysis. AOAC, Washington, D.C.
2. American Public Health Association. Standard Methods for the Examination of Dairy Products. APHA,
Washington, D.C.

3. APHA Technical Committee on Microbiological Methods for Foods. Compendium of Methods for the
Microbiological Examination of Foods. APHA, Washington, D.C.

4. U.S. Food and Drug Administration. Bacteriological Analytical Manual. Arlington, VA

http://www.fda.gov/Food/FoodScienceResearch/LaboratoryMethods/ucm2006949.htm

5. American Public Health Association. Standard Methods for the Examination of Water and Wastewater. APHA,
Washington, D.C.

6. Kodaka, Hidemasa, et al. 2005. "Comparison of the compact dry TC method with the standard pour plate method
(AOAC Official Method 966.23) for determining aerobic colony counts in food samples: performance-tested method."
Journal of AOAC International 88(6): 1702-1713.

ATCC is a registered trademark of the American Type Culture Collection.

Compact Dry™ is a trademark of Shimadzu Diagnostics Corporation.
Scan is a registered trademark of Interscience for Microbiology.

AOAC approval no. 010404

MicroVal approval no. RQA2007LR01 per ISO 16140:2003
NordVal approval no. 033

IFU-000761[A]

Manufactured for and distributed by:

1430 West McCoy Lane, Santa Maria, CA 93455, USA

Phone: (805) 346-2766 ext. 5658
Fax: (805) 346-2760
Website: HardyDiagnostics.com
Email: TechnicalServices@HardyDiagnostics.com
Ordering Information

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