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US3922203A Expired / Lapsed US ⏱️ 0.0 years remaining

Culture media in film format for conducting microbial analysis and method of producing the media and loading it into cassettes

Assignee: McDonnell Douglas Corp
•
Filing: 1973-07-17
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Granted: 1975-11-25
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Expires: 1993-07-17
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Abstract

Abstract A cassette used to analyze a carrier liquid for the presence of a specific microorganism therein has a passageway extending through it and the passageway is provided with filter and viewing wells arranged such that each viewing well is preceded by a filter well. The carrier liquid is introduced into the passageway at one end thereof. Each filter well contains a filter material capable of effecting a one log reduction in the microorganisms within the liquid as the liquid passes through the filter. Each viewing cell contains plugs having a culture medium therein which is selective to a specific microorganism in the sense that only that microorganism will grow in the culture medium and change the light-transmitting characteristics of the viewing wells. To load the filter wells a pad of filter material is placed over the ends of the filter wells and the filters are simultaneously stamped from the pad and driven into the filter wells. To load the viewing wells, a flexible sheet of culture medium is placed over the ends of the viewing wells and the plugs are stamped therefrom and simultaneously driven into the viewing wells. The flexible sheet of culture medium is formed by adding a film-forming agent to liquid culture medium, pouring the solution so formed onto a surface, and then evaporating volatile components of the solution. After the volatile components evaporate, the flexible film remains.. The film-forming agent may be gelatin and glycerin, or it may be polyvinyl alcohol.

Inventors

  • 👤 Jr Clifton Aldridge
  • 👤 Richard D Vannest

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-30 19:33
CPC Classifications
C; C12; C12Q; C12Q1/00; C12Q1/02; C12Q1/04; C12Q1/045; Y; Y10; Y10S; Y10S435/00; Y10S435/808

Claims Analysis

Total Claims: 11
Claim 1
Independent Claim 119 words
A METHOD OF LOADING A CASSETTE USED TO ANALYZE A CARRIER LIQUID FOR THE PRESENCE OF SPECIFIC MICROORGANISMS THEREIN, SAID CASSSETTE HAVING A RIGID BODY CONTAINING A PASSAGEWAY WHICH INCLUDES A PLURALITY OF VIEWING WELLS, THE INTERIORS OF WHICH ARE VISIBLE FROM OUTSIDE THE CASSETTE, EACH VIEWING WELL INITIALLY HAVING AT LEAST ONE OF ITS END OPENING OUTWARDLY THROUGH A FACE OF THE RIGID BODY, SAID METHOD COMPRISING PLACING A FLEXIBLE SHEET OF MATERIAL CONTAINING A CULTURE MEDIUM WHICH IS SELECTIVE TO THE SAID SPECIFIC MICROORGANISM OVER THE OPEN ENDS OF THE VIEWING WELLS; FORMING PLUGS FROM THE SHEET AND DRIVING THE PLUGS INTO THE VIEWING WELLS SUBSTANTIALLY CONTEMPORANEOUSLY; AND CLOSING THE INITIALLY OPEN ENDS OF THE VIEWING WELLS.
Claim 2
Independent Claim 119 words
A METHOD OF LOADING A CASSETTE USED TO ANALYZE A CARRIER LIQUID FOR THE PRESENCE OF SPECIFIC MICROORGANISMS THEREIN, SAID CASSSETTE HAVING A RIGID BODY CONTAINING A PASSAGEWAY WHICH INCLUDES A PLURALITY OF VIEWING WELLS, THE INTERIORS OF WHICH ARE VISIBLE FROM OUTSIDE THE CASSETTE, EACH VIEWING WELL INITIALLY HAVING AT LEAST ONE OF ITS END OPENING OUTWARDLY THROUGH A FACE OF THE RIGID BODY, SAID METHOD COMPRISING PLACING A FLEXIBLE SHEET OF MATERIAL CONTAINING A CULTURE MEDIUM WHICH IS SELECTIVE TO THE SAID SPECIFIC MICROORGANISM OVER THE OPEN ENDS OF THE VIEWING WELLS; FORMING PLUGS FROM THE SHEET AND DRIVING THE PLUGS INTO THE VIEWING WELLS SUBSTANTIALLY CONTEMPORANEOUSLY; AND CLOSING THE INITIALLY OPEN ENDS OF THE VIEWING WELLS.
Claim 3
Dependent Claim 20 words
The method of claim 1 wherein the sheet material contains gelatin and glycerol in addition to the selective culture medium.
Claim 4
Dependent Claim 19 words
The method of claim 1 wherein the sheet-like material contains polyvinyl alcohol in addition to the selective culture medium.
Claim 5
Dependent Claim 50 words
The method of claim 1 wherein the cassette contains filter wells and including the steps of placing a sheet of filter material over open ends of the filter wells forming filters sized to fit said filter wells from filter sheet, and positioning the filters as formed into the filter wells.
Claim 6
Dependent Claim 21 words
The method of claim 4 wherein the filters are punched from the filter sheets and driven into the filter wells contemporaneously.
Claim 7
Dependent Claim 116 words
A self-supporting flexible film for use in detecting the presence of a specific microorganism, said film comprising: water, a film forming agent, and a culture medium in and supported by the film forming agent, the film forming agent imparting body and flexibility to the film and being soluble in water, miscible in the culture medium, and nontoxic to the specific microorganism, the culture medium being selective in that the specific microorganism will be sustained by the culture medium and when so sustained only that microorganism will alter the light-transmitting characteristics of a solution of the culture medium and water, the culture medium being releasable from the film forming agent when the film is subjected to water.
Claim 8
Dependent Claim 116 words
A self-supporting flexible film for use in detecting the presence of a specific microorganism, said film comprising: water, a film forming agent, and a culture medium in and supported by the film forming agent, the film forming agent imparting body and flexibility to the film and being soluble in water, miscible in the culture medium, and nontoxic to the specific microorganism, the culture medium being selective in that the specific microorganism will be sustained by the culture medium and when so sustained only that microorganism will alter the light-transmitting characteristics of a solution of the culture medium and water, the culture medium being releasable from the film forming agent when the film is subjected to water.
Claim 9
Dependent Claim 15 words
A flexible material according to claim 6 wherein the film-forming agent includes gelatin and glycerin.
Claim 10
Dependent Claim 14 words
A flexible material according to claim 6 wherein the film-forming agent includes polyvinyl alcohol.
Claim 11
Dependent Claim 15 words
The sheet of claim 6 being from about 0.001 to about 0.015 inches in thickness.

References Cited (Backward Citations)

US2982699A Cited
US2998353A Cited
US3107204A Cited
US3416998A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1978-11-24 1979-05-26 1979-11-25 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1982-11-24 1983-05-26 1983-11-25 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1986-11-24 1987-05-26 1987-11-25 $7700.00 Window Closed / Lapsed

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