JP2000270840A - Colony counting system and usage thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the subject system enabling highly accurate counting operation even in the case of counting whitish, bright-colored colonies like ordinary live bacteria cultured in the standard agar medium, or even in the base of counting dark-colored colonies like Escherichia coli cultured in a deoxycolate agar medium. SOLUTION: This system has a transparent sample stage 1 loaded with a petri dish 5 containing a specimen, lighting sources 2, 3 giving irradiation light to the sample stage, a CCD camera 4 for photographing the specimen in the petri dish 5 irradiated by the lighting sources 2, 3, and an arithmetic means 8 for processing an image photographed by the CCD camera 4 and counting colonies of bacteria grown in the specimen medium; wherein a polyacrylate plate 6 (white light scattering plate) is detachably set up adjacently just under the sample stage 1. When whitish, bright-colored colonies like ordinary live bacteria cultured in the standard agar medium are to be counted, the plate 6 is detached, while when dark-colored colonies like Escherichia coli cultured in a deoxycolate agar medium are to be counted, the plate 6 is inserted just under the sample stage 1 and attached it to the stage 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a colony counting device for counting the number of colonies such as bacteria and microorganisms grown on a culture medium and a method of using the same.

[0002]

2. Description of the Related Art As a method for counting the number of colonies of bacteria and microorganisms present in foods and the like, conventionally, the number of colonies of bacteria grown in a medium layer after culturing a specimen in a medium in a petri dish for a predetermined time has been known. A counting method is generally employed. In this method, the number of colonies is also visually counted.However, in order to achieve more accurate measurement, the culture medium in which the specimen has been cultured is irradiated with a predetermined illumination from a light source, and is illuminated. Take an image with imaging means such as a CCD camera,
A method of analyzing the image signal output from the computer by performing predetermined image processing using a computer is also employed.

[0003]

However, according to this method, high-precision measurement is possible when counting whitish light-colored colonies such as general viable bacteria cultured on a standard agar medium. When counting dark colonies such as coliforms cultured on an agar medium, there is a problem that it is difficult to perform highly accurate counting because the contrast between the medium and the colony to be measured is insufficient. Particularly in the food field, it is indispensable to measure the number of E. coli under the Food Sanitation Law. Therefore, early development of a solution to this problem has been desired.

[0004]

Accordingly, the present invention solves the above-mentioned problems in the prior art, and can be used for deoxygenation even when counting whitish light-colored colonies such as general viable bacteria cultured on a standard agar medium. An object of the present invention is to provide a colony counting device capable of performing high-precision counting even when counting dark colonies such as coliforms cultured on a collate agar medium, and a method of using the same.

That is, a colony counting apparatus according to the present invention comprises a transparent sample stage on which a petri dish containing a specimen is placed, an illumination light source for applying irradiation light to the sample stage, and an illumination light source for irradiating the sample stage. Imaging means for imaging the specimen in the Petri dish, and arithmetic means for processing the image captured by the imaging means and counting the number of bacterial colonies grown in the culture medium of the specimen, A white light scattering plate is provided detachably adjacent immediately below. The white light scattering plate is preferably an acrylic plate. As the illumination light source, either a transmission illumination light source disposed below the sample stage or a reflection illumination light source disposed above the sample stage can be used.

[0006] The present invention further relates to a method of using the colony counting device having the above-mentioned configuration. When the specimen is a general viable bacterium cultured on a standard agar medium, the white light scattering plate is removed and the specimen is deoxycholate agar. In the case of a group of Escherichia coli cultured in a medium, it is characterized in that an image is taken by the above-mentioned imaging means with a white light scattering plate attached. By attaching the white light scattering plate, the white light spectrum of the illumination light from the transmission illumination light source is diffused, and the contrast between the dark Escherichia coli colony and other culture medium portions can be enhanced to accurately capture the colony.

[0007]

FIG. 1 shows a schematic structure of the apparatus of the present invention. A transmission illumination light source 3 is provided below a sample stage 1 made of a glass plate. Is provided with an illumination light source 2 for reflection. Reference numeral 4 denotes a CCD camera, and the sample stage 1 illuminated by the transmission illumination light source 3 or the reflection illumination light source 2
An imaging means for imaging the specimen in the upper petri dish 5 is constituted. An acrylic plate 6 can be detachably inserted directly below the sample stage 1. The image picked up by the CCD camera 4 is output to the image processing device 7 and subjected to predetermined image processing, and thereafter, the arithmetic device 8 counts the number of colonies in the sample. The counting result is displayed on the display 9 together with the image.

This apparatus is used to count the number of colonies of bacteria (including microorganisms and somatic cells) cultured in a culture medium. Specifically, the apparatus is used in which a specimen is cultured in a standard agar medium. The acrylic plate 6 is removed when the microorganism is a general viable bacterium, and when the specimen is a coliform group cultured on a deoxycholate agar medium, an image is taken by the CCD camera 4 with the acrylic plate 6 attached.

FIG. 2 shows a screen of a display 9 when a general live bacterium cultured on a standard agar medium is contained in a petri dish 5 as a specimen and imaged by a CCD camera 4 with an acrylic plate 6 attached. Shows a screen of the display 9 when the same sample is stored in the petri dish 5 and imaged by the CCD camera 4 with the acrylic plate 6 removed. As can be seen from a comparison of these figures,
If the colony has a whitish bright color like a general viable bacterium cultured on a standard agar medium, contrast is lost instead of imaging with the acrylic plate 6 attached. When the measurement was not possible and the image was taken with the acrylic plate 6 removed, even with the result of the image processing by the computer, the same high-precision counting as in the case of visual observation was possible. In this measurement example, when the acrylic plate 6 was attached, only 23 colonies could be counted, but by removing the acrylic plate 6, 41 colonies could be counted.

[0010] On the other hand, FIG. 4 shows a screen of a display 9 when an Escherichia coli group cultivated on a deoxycholate agar medium is contained in a petri dish 5 as a specimen and imaged by a CCD camera 4 with an acrylic plate 6 attached. FIG. 5 shows a CCD image of the same sample with the acrylic plate 6 removed.
4 shows a screen of a display 9 when an image is captured by the camera 4.
As can be understood from the comparison of these figures, when the colonies show a dark color such as the coliforms cultured on the deoxycholate agar medium, when the image is taken with the acrylic plate 6 removed, the contrast is not clear, so that accurate images are obtained. Although the measurement could not be performed, the chromaticity range of the color image was expanded by attaching the acrylic plate 6 to facilitate color extraction, and the measurement accuracy was greatly improved. In this measurement example, when the acrylic plate 6 was removed, only 268 colonies could be counted, but by attaching the acrylic plate 6, 414 colonies could be counted.

The apparatus shown in FIG. 1 is provided with an illumination light source 3 for transmission and an illumination light source 2 for reflection, and one of them is used as a light source at the time of imaging. Generally, it is possible to observe all the colonies present in the culture medium by using the illumination light source 3 for transmission, but the transmittance deteriorates due to poor light transmittance of the medium color or diffusion of bacteria. In such cases, clear separation may not be possible. In such a case, it is preferable to use the reflection illumination light source 2 instead of the transmission illumination light source 3. The use of the illumination light source for reflection 2 is also advantageous when measuring colonies on a sample smear agar medium in which a sample is smeared on the surface of a culture medium or when it is desired to store an image captured by the CCD camera 4 at the same level as visual observation. is there. As described above, the apparatus of FIG. 1 has an advantage that the transmission illumination light source 3 and the reflection illumination light source 2 can be switched and used as needed, but this configuration is not essential to the present invention. Instead, only a generally used transmission illumination light source may be provided, or only a reflection illumination light source may be provided.

[0012]

According to the present invention, when counting whitish light-colored colonies such as general live bacteria cultured on a standard agar medium, imaging is performed by removing the white light scattering plate, and When counting dark colonies such as coliforms cultured on deoxycholate agar medium, all images can be obtained with high precision by imaging with a white light scattering plate inserted and mounted directly below the sample stage. Counting can be performed.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a colony counting device according to one embodiment of the present invention.

FIG. 2 is a schematic diagram showing a display screen when an image of a sample in which a general viable bacterium cultured on a standard agar medium is accommodated in a petri dish with an acrylic plate attached is taken using the apparatus of FIG. 1; .

FIG. 3 is a schematic view showing a display screen when an image of the same sample as that shown in FIG. 2 is stored in a petri dish with an acrylic plate removed.

FIG. 4 is a schematic diagram showing a display screen when an image of Escherichia coli cultivated on a deoxycholate agar medium contained in a petri dish is taken with an acrylic plate attached using the apparatus of FIG. 1; .

FIG. 5 is a schematic diagram showing a display screen when an image of the same sample as in FIG. 4 stored in a petri dish is taken with an acrylic plate removed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sample stage 2 Illumination light source for reflection 3 Illumination light source for transmission 4 CCD camera (imaging means) 5 Petri dish 6 Acrylic plate (white light scattering plate) 7 Image processing device 8 Arithmetic device 9 Display

 ──────────────────────────────────────────────────の Continued on the front page F term (reference) 4B029 AA07 BB02 BB06 CC02 CC07 FA10 4B063 QA01 QQ06 QQ07 QS39 QX01 QX10

Claims (4)

[Claims] 1. A transparent sample stage on which a petri dish containing a specimen is placed, an illumination light source for applying irradiation light to the sample stage, and an image of the specimen in the petri dish irradiated by the illumination light source. An imaging means, and an arithmetic means for processing the image captured by the imaging means and counting the number of bacterial colonies that have grown in the culture medium of the specimen, wherein a white light is provided immediately below the sample stage. A colony counting device, wherein a scattering plate is detachably provided. 2. The colony counting device according to claim 1, wherein the white light scattering plate is an acrylic plate. 3. The colony counting system according to claim 1, wherein the illumination light source is one of a transmission illumination light source disposed below the sample stage and a reflection illumination light source disposed above the sample stage. apparatus. 4. The white light scattering plate is removed when the specimen is a general viable bacterium cultured on a standard agar medium, and the white light scattering plate is removed when the specimen is a coliform group cultured on a deoxycholate agar medium. 4. The method for using a colony counting device according to claim 1, wherein an image is taken by the image taking means in a state where the device is attached.