Indirect microbial detection

Claim 2

An indirect method for detecting substances which influence microbial growth, which comprises: separating a growth medium suitable for microorganisms into two compartments by a first semipermeable membrane barrier that is impermeable to microorganisms; providing at least one additional semipermeable membrane barrier in one of the compartments and inoculating this compartment with microorganisms; placing two electrodes in the other of the two compartments; maintaining said electrodes in fluid or gaseous contact with said microorganisms; bringing the compartment containing microbial growth into contact with an environment containing at least one substance that influences microbial growth and is permeable to the one additional semipermeable membrane; and detecting and monitoring the change in potential between the two electrodes with a potentiometer having an impedance equal to at least one megohm to detect the substance which influences microbial growth in said environment.

Claim 3

The method of claim 1 wherein the environment substance influencing growth is selected from the group consisting of toxins, bacteriophages and water pollutants.

Claim 4

Apparatus for indirectly detecting and measuring microbial growth comprising: a container; a first chamber in said container housing a microbial growth medium and containing microorganisms said first chamber being provided with at least one semipermeable membrane in a sidewall thereof to permit microorganism growth influencing environment to contact the microbial growth medium; a second chamber in said container housing a microbial growth medium; a semipermeable membrane barrier impermeable to said microorganisms disposed between and maintaining said first and second chambers separate; a pair of electrodes disposed in said second chamber and embedded in the said microbial growth medium; an electric circuit connected to said pair of electrodes; detecting means connected to said electric circuit to detect changes in electrical potential between said pair of electrodes; said detecting means being a potentiometer with an impedance equal to at least one megohm; whereby, microbial growth in said first chamber will produce charged particles that permeate said semipermeable barrier to contact said pair of electrodes and cause a change in electrical potential therebetween that is detected by said detecting means.

Claim 5

Apparatus for indirectly detecting and measuring microbial growth comprising: a container; a first chamber in said container housing a microbial growth medium and containing microorganisms said first chamber being provided with at least one semipermeable membrane in a sidewall thereof to permit microorganism growth influencing environment to contact the microbial growth medium; a second chamber in said container housing a microbial growth medium; a semipermeable membrane barrier impermeable to said microorganisms disposed between and maintaining said first and second chambers separate; a pair of electrodes disposed in said second chamber and embedded in the said microbial growth medium; an electric circuit connected to said pair of electrodes; detecting means connected to said electric circuit to detect changes in electrical potential between said pair of electrodes; said detecting means being a potentiometer with an impedance equal to at least one megohm; whereby, microbial growth in said first chamber will produce charged particles that permeate said semipermeable barrier to contact said pair of electrodes and cause a change in electrical potential therebetween that is detected by said detecting means.

Claim 6

The apparatus of claim 3 wherein said potentiometer is connected to a strip chart recorder that permanently records the changes in electrical potential between said electrodes.

Claim 7

The apparatus of claim 3 wherein said microbial growth medium is selected from the group consisting of: brain-heart infusion, trypticase soy broth (TSB), trypticase soy broth +CO 2 , phenol red broth base +1% glucose, and litmus milk.

Claim 8

The apparatus of claim 3 wherein said first and said second chambers are provided with a separable threaded joint connection.