Capacitor for detecting viable microorganisms

Abstract

This invention relates to a capacitor comprising two electrical conductors separated by a dielectric, the dielectric comprising microorganisms. The dielectric may comprise a biological indicator. This invention relates to a process for determining whether the microorganisms are alive or dead. The number of microorganisms can be determined. This invention relates to a process for testing the efficacy of a sterilization process using the capacitor.

1 - 116 . (canceled) 
     
     
         117 . A process for counting test microorganisms on a treated biological indicator using a capacitance test system comprising a capacitor and a capacitance bridge, the process comprising:
 (a) calibrating the capacitance test system to establish (1) an all dead capacitance control value using an all dead control biological indicator containing test microorganisms where all of the test microorganisms are dead, and (2) an all live capacitance control value using a live control biological indicator containing test microorganisms where all of the test microorganisms are alive, the all dead control biological indicator and the all live control biological indicator being the same except for the presence of dead or live test microorganisms, the all dead and all live control biological indicators having the same estimated number of test microorganisms;   (b) determining the difference between the all live capacitance control value and the all dead capacitance control value to obtain a net capacitance control value;   (c) dividing the net capacitance control value by the estimated number of test microorganisms on the all live control biological indicator to obtain a capacitance value for each test microorganism;   (d) determining the capacitance value for a treated biological indicator;   (e) determining the difference between the capacitance value for the treated biological indicator in (d) and the all dead capacitance control value in (a) to obtain a net capacitance treated value; and   (f) dividing the net capacitance treated value in (e) by the capacitance value for each test microorganism in (c) to obtain the number of live test microorganisms on the treated biological indicator.   
     
     
         118 . A process for counting spores on a treated biological indicator using a capacitance test system comprising a capacitor and a capacitance bridge, the process comprising:
 (a) calibrating the capacitance test system to establish (1) an all dead capacitance control value using an all dead control biological indicator containing spores where all of the spores are dead, and (2) an all live capacitance control value using a live control biological indicator containing spores where all of the spores are alive, the all dead control biological indicator and the all live control biological indicator being the same except for the presence of dead or live spores, the all dead and all live control biological indicators having the same estimated number of spores;   (b) determining the difference between the all live capacitance control value and the all dead capacitance control value to obtain a net capacitance control value;   (c) dividing the net capacitance control value by the estimated number of spores on the all live control biological indicator to obtain a capacitance value for each spore;   (d) determining the capacitance value for a treated biological indicator;   (e) determining the difference between the capacitance value for the treated biological indicator in (d) and the all dead capacitance control value in (a) to obtain a net capacitance treated value; and   (f) dividing the net capacitance treated value in (e) by the capacitance value for each spore in (c) to obtain the number of live spores on the treated biological indicator.   
     
     
         119 - 141 . (canceled) 
     
     
         142 . A process for counting microorganisms on a carrier using a capacitance test system comprising a capacitor and a capacitance bridge, the process comprising:
 (a) establishing a capacitance value for the carrier;   (b) establishing a capacitance value for the carrier with a control deposit on the carrier of a known quantity of microorganisms;   (c) determining the difference between the capacitance value in (b) and the capacitance value in (a) to obtain a net capacitance value for the known quantity of microorganisms in (b);   (d) dividing the net capacitance value for the known quantity of microorganisms in (c) by the known quantity of microorganisms in (b) to obtain a capacitance value for each microorganism;   (e) determining a capacitance value for the carrier with a test deposit of microorganisms on the carrier;   (f) determining the difference between the capacitance value for the carrier with the test deposit of microorganisms in (e) and the capacitance value for the carrier in (a) to obtain a net capacitance test value; and   (g) dividing the net capacitance test value in (f) by the capacitance value for each microorganism in (d) to obtain the number of microorganisms in the test deposit of microorganisms in (e).   
     
     
         143 - 146 . (canceled) 
     
     
         147 . A process for counting spores on a carrier using a capacitance test system comprising a capacitor and a capacitance bridge, the process comprising:
 (a) establishing a capacitance value for the carrier;   (b) establishing a capacitance value for the carrier with a control deposit on the carrier of a known quantity of spores;   (c) determining the difference between the capacitance value in (b) and the capacitance value in (a) to obtain a net capacitance value for the known quantity of spores in (b);   (d) dividing the net capacitance value for the known quantity of spores in (c) by the known quantity of spores in (b) to obtain a capacitance value for each spore;   (e) determining a capacitance value for the carrier with a test deposit of spores on the carrier;   (f) determining the difference between the capacitance value for the carrier with the test deposit of spores in (e) and the capacitance value for the carrier in (a) to obtain a net capacitance test value; and   (g) dividing the net capacitance test value in (f) by the capacitance value for each spore in (d) to obtain the number of spores in the test deposit of spores in (e).   
     
     
         148 - 164 . (canceled) 
     
     
         165 . A process for counting microorganisms in a liquid using a capacitance test system comprising a capacitor and a capacitance bridge, the process comprising:
 (a) establishing a capacitance value for the liquid;   (b) establishing a capacitance value for the liquid in (a) with a control sample of a known quantity of microorganisms in the liquid;   (c) determining the difference between the capacitance value in (b) and the capacitance value in (a) to obtain a net capacitance value for the known quantity of microorganisms in (b);   (d) dividing the net capacitance value for the known quantity of microorganisms in (c) by the known quantity of microorganisms in (b) to obtain a capacitance value for each microorganism;   (e) determining a capacitance value for the liquid in (a) with a test sample of microorganisms in the liquid;   (f) determining the difference between the capacitance value for the liquid with the test sample of microorganisms in (e) and the capacitance value for the liquid in (a) to obtain a net capacitance test value; and   (g) dividing the net capacitance test value in (f) by the capacitance value for each microorganism in (d) to obtain the number of microorganisms in the test sample of microorganisms in (e).   
     
     
         166 - 184 . (canceled) 
     
     
         185 . The process of  claim 117  wherein the capacitance bridge has an accuracy level of about 1 μF or less. 
     
     
         186 . The process of  claim 117  wherein the capacitor comprises a dielectric, the capacitance of the dielectric being in the range from about 0.1 nF to about 20 mF. 
     
     
         187 . The process of  claim 118  wherein the spores on the all dead control biological indicator, the all live control biological indicator, and the treated biological indicator comprise bacterial spores. 
     
     
         188 . The process of  claim 118  wherein the spores on the all dead control biological indicator, the all live control biological indicator, and the treated biological indicator comprise spores of the  Bacillus  or  Clostridia  genera. 
     
     
         189 . The process of  claim 118  wherein the spores on the all dead control biological indicator, the all live control biological indicator, and the treated biological indicator comprise spores of  Geobacillus stearothermophilus, Bacillus atrophaeus, Bacillus sphaericus, Bacillus anthracis, Bacillus pumilus, Bacillus coagulans, Clostridium sporogenes, Clostridium difficile, Clostridium botulinum, Bacillus subtilis globigii, Bacillus cereus, Bacillus circulans , or a mixture of two or more thereof. 
     
     
         190 . The process of  claim 118  wherein the spores on the all dead control biological indicator, the all live control biological indicator, and the treated biological indicator comprise  Geobacillus stearothermophilus  spores,  Bacillus atrophaeus  spores, or a mixture thereof. 
     
     
         191 . The process of  claim 118  wherein the all dead control biological indicator, the all live control biological indicator, and the treated biological indicator comprise spores on a carrier, the spore population on the carrier for each biological indicator being in the range from about 500,000 to about 4,000,000 spores. 
     
     
         192 . The process of  claim 118  wherein the capacitor comprises two electrical conductors, and the all dead control biological indicator, the all live control biological indicator and the treated biological indicator comprise spores on a carrier, the carrier for each biological indicator comprising paper, plastic, glass, ceramics, metal foil, one or both conductors of the capacitor, or a combination of two or more thereof. 
     
     
         193 . The process of  claim 118  wherein the all dead control biological indicator, the all live control biological indicator and the treated biological indicator comprise spores on a carrier, the carrier for each biological indicator having a length in the range from about 1 to about 5 cm, a width in the range from about 0.1 to about 1 cm, and a thickness in the range from about 0.5 to about 3 mm. 
     
     
         194 . The process of  claim 117  wherein the capacitor comprises electrical conductors, the electrical conductors comprise aluminum, copper, silver, gold, platinum, or a combination of two or more thereof. 
     
     
         195 . The process of  claim 117  wherein the capacitor comprises electrical conductors, the electrical conductors comprising indium tin oxide on glass. 
     
     
         196 . The process of  claim 117  wherein the capacitor comprises two electrical conductors, each electrical conductor having a length in the range from about 1 to about 5 cm, and a width in the range from about 0.5 to about 3 cm. 
     
     
         197 . The process of  claim 117  wherein the capacitor comprises two electrical conductors, the separation between the electrical conductors being in the range from about 0.5 to about 5 mm. 
     
     
         198 . The process of  claim 118  wherein all of the spores on the treated biological indicator are dead. 
     
     
         199 . The process of  claim 118  wherein some of the spores on the treated biological indicator are alive, the number of live spores being in the range from 1 to about 4,000,000. 
     
     
         200 . The process of  claim 117  wherein the all dead capacitance control value is in the range from about 0.1 nF to about 20 mF. 
     
     
         201 . The process of  claim 117  wherein the all live capacitance control value is in the range from about 0.1 nF to about 20 mF. 
     
     
         202 . The process of  claim 118  wherein the capacitance value for each spore is in the range up to about 10 pF. 
     
     
         203 . The process of  claim 118  wherein live spores are detected within a period of time of up to about 2000 seconds. 
     
     
         204 . The process of  claim 118  wherein it is determined that all spores are dead within a period of time of up to about 2000 seconds.