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FAQs
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Question: Where can I find material safety data sheets (MSDS)?
Answer: All material safety data sheets are found as part of the product information under "Publications".

Question: Where can I find certificates?
Answer: All certificates are found as part of the product information under "Publications".


COMPACT DRY

Question: Can Compact Dry Plates be frozen?
Answer: Yes Compact Dry plates can be frozen - however they should be equalibratze to room temperature before use.

Question: How do I out a solid food sample on the Compact Dry plate
Answer: Please use 25 gr of the your solid food sample and mix with 225 ml buffer (e.g petone water or PBS). Than homogenize and filtrate if needed
Now you should me a dilituin series like undiluted; 1:10, 1:100 and 1: 1000
Please add 1 ml of each dilution on the Compact Dry plate

Question: How many bacteria can be read on a Compact Dry plate?
Answer: It´s possible to grow up to 200 colonies on the Compact Dry plates.However we recommed for more easy counting not to add more than 50 colonies on the plates. If you do not know how many bacteria your sample contain we recommed to make a dilution series first time.

Question: What happen if I add more than 200 colonies on the Compact Dry Plate?
Answer: If you add sample with very high contamination ( > 200 colonies / ml ) Compact Dry will not be able to show you single colonies. The amount of chromogenic substrate in the media is not enough to color every colony.
Samples with a bacteria load over 200 CFU/ ml will result normally in a pink or coloured plate. It´s not possible to count please prepare a dilution series.
Samples with a bacteria load much higher 200 CFU/ ml will result sometimes in an even white plate. This plate looks empty however ist full covered by bacteria


Compact Dry
Once 1 mL of sample is placed onto a plate, the liquid sample is diffused evenly over the whole plate, and dehydrated film medium is swollen.

Question: 1 mL of sample is not diffused evenly over the whole plate.
Answer: Samples extracted from foodstuffs having high viscosity such as honey and mayonnaise should be appropriately diluted and inoculated. The viable count in samples is calculated by multiplying the number of developed colony by dilution ratio.

Question: Precaution in case that sample extracts indicating high or low pH are inoculated.
Answer: Since dehydrated film medium is swollen by adding a sample solution, samples should be diluted using sterilized physiological saline, or neutralized around pH 7.


Compact Dry TC
All colonies growing in CD TC turn red by the action of TTC.

Question: In case that colonies besides colonies turning red grow.
Answer: Yeast grows as pale pink or white colony. On the other hand, mold also grows in CD TC, but particular color tone and morphology of mold is observed instead of turning red

Question: Colonies cannot be counted because of widespread shapes.
Answer: Colonies formed by bacteria having high motility, and ones on the surface of film medium tend to spread over a plate. In these cases, since a relatively-dark part is observed in the center of widespread colony, this part should be counted. Colony spreading along the pattern of nonwoven cloth is the same case as the above-mentioned.

Question: It is difficult to count small sizes of colonies.
Answer: Small sizes of colonies should be counted on the white background, or by lighting up.

Question: The color tone of colony is not clear-red.
Answer: There are cases which growing bacteria produce particular chromogen such as Staphylococcus and so on. In this case, the color tone may change clear-red into mixed color tone.


Compact Dry EC
Film medium of Compact Dry EC contains two chromegens, i.e. (namely) Magenta-gal for coliform, and X-Gul for E.coil.

Question: Although colony formation cannot be observed, whole area is stained in red-purple or blue.
Answer: Film medium of Compact Dry EC contains enzyme-substrates. In case of samples containing a certain enzyme such as yogurt and liver and so on, whole area of plate is stained by sample-derived enzyme without coliform. This phenomenon may be improved by sample dilution.

Question: Colonies cannot be counted because of widespread shapes.
Answer: Colonies formed by bacteria having high motility, and ones on the surface of film medium tend to spread over a plate. In these cases, since a relatively-dark part is observed in the center of widespread colony, this part should be counted. Colony spreading along the pattern of nonwoven cloth is the same case as the above-mentioned.

Question: It is difficult to count small sizes of colonies.
Answer: Small sizes of colonies should be counted on the white background, or by lighting up.

Question: Regarding E. coil O-157
Answer: Since E. coil O-157 does not produce ß-glucuronidase, developed-colonies turn red-purple in stead of blue.

Question: Although colonies cannot be form, blue dots are observed. Blue dots are picked up and cultivated, resulting that they are not coliforms.
Answer: Since film medium of Compact Dry EC contains enzyme-substrates, there are cases which the substrates are degraded by enzyme contained in bacteria in spite of growth-inhibition of gram-positive bacteria, resulting that blue dots are observed. In addition, since Compact Dry EC contains tryptophan, indol test can be easily undertaken for identification of E.coil.


Compact Dry CF
Film medium of Compact Dry CF contains X-gal for coliform as an enzyme-substrate.

Question: Although colony formation cannot be observed, whole area is stained in blue.
Answer: Film medium of Compact Dry CF contains enzyme-substrates. In case of samples containing a certain enzyme such as yogurt and liver and so on, whole area of plate is stained by sample-derived enzyme without coliform. This phenomenon may be improved by sample dilution.

Question: Colonies cannot be counted because of widespread shapes.
Answer: Colonies formed by bacteria having high motility, and ones on the surface of film medium tend to spread over a plate. In these cases, since a relatively-dark part is observed in the center of widespread colony, this part should be counted. Colony spreading along the pattern of nonwoven cloth is the same case as the above-mentioned.

Question: It is difficult to count small sizes of colonies.
Answer: Small sizes of colonies should be counted on the white background, or by lighting up.


Compact Dry YM
Film medium of Compact Dry YM contains X-phos for Yeast and Mold as an enzyme-substrate.

Question: Stained- and colorless-mixed colonies are observed.
Answer: Since film medium contains an enzyme-substrate (X-phos), most fungi are stained. On the other hand, particular color tone and morphology of mold or yeast may be observed instead of turning blue. In this case, colonies should be counted on the white or black background, or by lighting up.

Question: Although colony formation cannot be observed, whole area is stained in blue.
Answer: Film medium of Compact Dry YM contains enzyme-substrates. In case of samples containing a certain enzyme, whole area of plate is stained by sample-derived enzyme without fungi. This phenomenon may be improved by sample dilution.

Question: Colonies cannot be counted because of widespread shapes.
Answer: Compact Dry YM is suitable for observation of fungus pattern. On the other hand, relatively-rapid growth of mold tends to spread over the surface of film medium. In order to avoid the disadvantage, counting the number of mold in the middle period of cultivation is recommended; namely the number of mold can be counted more precisely by counting in day 4 and day 7 after inoculation.


Compact Dry SA
Compact Dry can detect S.aureus by using selective agent and egg-yolk reaction.

Question: Egg-yolk reaction is not clear.
Answer: Egg-yolk reaction is affected by the amount of air. Therefore, as compared with the surface of film medium, Egg-yolk reaction at the bottom of film medium tends to be unclear.
In this case, colonies and Egg-yolk reaction should be confirmed on the white or black background, or by lighting up.

Question: Immediately a sample is inoculated, color tone of medium is changed.
Answer: Compact Dry SA contains pH indicator. In the case of samples having high- or low-pH, color tone of medium may be changed. Since dehydrated film medium is swollen by adding a sample solution, samples should be diluted using sterilized physiological saline, or neutralized around pH 7.

Question: Non-yellow colonies indicating Egg-yolk reaction are observed. Yellow colonies not indicating Egg-yolk reaction are observed.
Answer: Although most S.aureu indicate mannitol (+) and Egg-yolk reaction (+), a portion of S.aureu indicating mannitol (-) or Egg-yolk reaction (-) exists. In case of doubt, confirmation test should be done.


Compact Dry SL
Compact Dry SL can detect Salmonella by change of medium color into yellow, production of hydrogen sulfide, and enzyme-substrate.

Question: Colonies cannot be counted because of widespread shapes.
Answer: Colonies formed by bacteria having high motility, and ones on the surface of film medium tend to spread over a plate. In these cases, since a relatively-dark part is observed in the center of widespread colony, this part should be counted. Colony spreading along the pattern of nonwoven cloth is the same case as the above-mentioned.

Question: Please tell us how to measure Salmonella.
Answer: Although Compact Dry SL can detect Salmonella by change of medium color into yellow, production of hydrogen sulfide, and enzyme-substrate, there are cases which do not both produce hydrogen sulfide and degrade enzyme-substrate. In the case like this, bacteria should be picked up from yellow parts of film medium and be inoculated in selective medium, or be examined by serological methods. Since the yellow part contains the same bacterium number as pure culture, streak culture is needed using selective isolation media such as DHL. After that, biochemical testing, or agglutination testing should be done.


Compact Dry VP
Compact Dry VP can detect V.parahaemolyticus, V.cholerae, V.mimicus, V.vulnificus and Vibrio strain containg V.alginolyticus by using selective agent and enzyme-substrate.

Question: Although colony formation cannot be observed, whole area is stained.
Answer: Film medium of Compact Dry VP contains enzyme-substrates. In case of samples containing a certain enzyme such as yogurt and liver and so on, whole area of plate is stained by sample-derived enzyme. This phenomenon may be improved by sample dilution.

Question: Colonies cannot be counted because of widespread shapes.
Answer: Colonies formed by bacteria having high motility, and ones on the surface of film medium tend to spread over a plate. In these cases, since a relatively-dark part is observed in the center of widespread colony, this part should be counted. Colony spreading along the pattern of nonwoven cloth is the same case as the above-mentioned.

Question: Colonies, different from Vibrio strain, or colored spots are growed.
Answer: Although gram-positive bacteria are inhibited, there are cases which enzyme-substrate is degraded by enzyme activity derived from bacteria, resulting that spots are stained. On the other hand, there are cases which growth of coliforms is recognized in samples contaminated by a large amount of coliforms. In this case, Cytochrom oxydase test should be done for differential identification.



L U M I N O M E T E R

Question: What is ATP?
Answer
Adenosine-5'-triphosphate (ATP) is a multifunctional nucleotide used in cells as a coenzyme. It is often called the "molecular unit of currency" of intracellular energy transfer. ATP transports chemical energy within cells for metabolism. It is produced by photophosphorylation and cellular respiration and used by enzymes and structural proteins in many cellular processes, including biosynthetic reactions, motility, and cell division. One molecule of ATP contains three phosphate groups, and it is produced by ATP synthase from inorganic phosphate and adenosine diphosphate (ADP) or adenosine monophosphate (AMP). Metabolic processes that use ATP as an energy source convert it back into its precursors. ATP is therefore continuously recycled in organisms, with the human body turning over its own weight in ATP each day.

Question: Do I measure bacteria with the Lumitester PD10N or PD 20?
Answer: No you do not measure you measure the paramater AMP and ATP. They are a marker for cleanlees. All bacteria contain AMP and ATP

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