Chemistry: molecular biology and microbiology – Apparatus – Bioreactor
Patent
1995-03-21
1997-12-09
Redding, David A.
Chemistry: molecular biology and microbiology
Apparatus
Bioreactor
4353092, 4353094, C12M 300
Patent
active
056959885
DESCRIPTION:
BRIEF SUMMARY
The present invention relates to a culture device for sampling micro-organisms and/or counting micro-organisms. The present invention also relates to apparatus by means of which Such a culture device can be prepared.
Microbial count tests have become a useful sanitary control tool for monitoring sanitation and quality levels of food plants to ensure that products are safe and wholesome. The tests involve transfer of micro-organisms from cleaned and sanitised test surfaces onto a culture agar medium (CAM) which allows growth of a wide range of micro-organisms. After a period of incubation, each microbial cell develops into a visible colony of cells. The number of colonies provides a measure of the number of micro-organisms on the test surface.
Various methods are available for assessment of microbiological status of food contact surfaces in equipment such as piping, containers, tables and conveyors which are in contact with food products. Of these methods, the rinsing, swabbing and agar contact methods have been considered as satisfactory and have gained general acceptance.
In the agar contact method a replicate organism direct agar contact (RODAC) plate is used. The RODAC plate provides a simple agar contact tool for sampling surfaces. It is useful for monitoring the sanitary quality of surfaces used in food industries and hospitals. The RODAC plate is best suited for flat smooth impervious surfaces such as ceiling, wall and floor surfaces and surfaces of tables, containers and conveyors.
The RODAC plate has a rim and is filled with CAM which has a slightly convex surface with the centre of its meniscus rising above the rim. The surface of the CAM is pressed against the test surface to be sampled. It is necessary to make good contact of the agar with the test surface. Accordingly when sampling, care has to be taken to ensure that the entire agar meniscus contacts the test surface: a rolling uniform pressure on the back of the plate to effect contact aids in achieving this.
A disadvantage inherent in the rinsing, swabbing and agar contact methods is that uniformity and consistency in sampling depend primarily on the skill of persons taking the samples. Technicians need to be trained in sampling technique in order to obtain uniform and meaningful results.
In particular in the agar contact method the filling of the RODAC plate with CAM to achieve a slightly convex surface is a slow, cares and exacting process. Additionally it is not sufficient simply to press the CAM of the filled plate against the test surface since only that part of the surface of the CAM within the curved edge portion of the meniscus would contact the test surface. This part of the surface is of indefinite area. Thus the area of the test surface contacted would be indefinite and consequently an accurate account of microorganisms per unit area of the test surface would not be obtainable.
The present invention enables the above-mentioned disadvantage to be overcome and provides, at least in preferred embodiments, additional advantages.
In accordance with a first aspect of the invention, there is provided a culture device comprising a body of culture medium and supporting means for maintaining the integrity of the body of culture medium, the culture medium providing a surface (referred to below as the "the culturing surface") having a defined endless boundary or perimeter, the body of culture medium protruding from and the culturing surface being spaced from any aforesaid means disposed externally of the body of culture medium.
The endless boundary or perimeter is defined by a side surface on contiguous side surfaces of the culture medium, which side surface or surfaces meet the culturing surface, preferably abruptly, along an endless line or endless series of lines at an angle substantially differing from 180.degree., preferably at an angle of 90.degree., so that the boundary or perimeter is precisely defined.
The defined boundary or perimeter of the culturing surface enables its surface area to be clearly ascertained. This enables the numbe
REFERENCES:
patent: 3203870 (1965-08-01), Andelin
patent: 3751341 (1973-08-01), Seitz et al.
patent: 3881993 (1975-05-01), Freake
patent: 3902972 (1975-09-01), Beckford
patent: 4250256 (1981-02-01), Weilinger et al.
patent: 4598050 (1986-07-01), Brown
patent: 4634676 (1987-01-01), Sapatino
patent: 4717667 (1988-01-01), Provonchee
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