The present disclosure provides a technique for quantitatively detecting alkaline phosphatase (ALP) activities in seawater and other aquatic environments, based on surface-enhanced Raman spectroscopy by taking 5-bromo-4-chloro-3-indolyl phosphate (BCIP) as a substrate and dimethyl sulfoxide (DMSO) as an internal standard. Results show that ALP activity has a good linear correlation with the intensity ratio of a characteristic Raman peak to that of the internal standard peak (600 cm.sup.−1/677 cm.sup.−1) (R.sup.2=0.977). The technique was successfully applied to detect ALP activity of a seawater sample. By extension this technique can also be used in detecting the activity of other microbial extracellular enzymes (e.g., aminopeptidase) in seawater and thus, lays a solid scientific foundation for in-situ detection of the activities of other extracellular enzymes in seawater and other aquatic environments.

A medium containing (A) a chromogenic substance which develops a color when decomposed by β-glucosidase or a fluorogenic substance which develops a fluorescence when decomposed by β-glucosidase; (B) a chromogenic substance which develops a color when decomposed by phosphatidyl inositol-specific phospholipase C or a fluorogenic substance which develops a fluorescence when decomposed by phosphatidyl inositol-specific phospholipase C; and (C) a sugar that is useful for the detection of Listeria monocytogenes and/or Listeria ivanovii.

A device for differentially enumerating colonies of coliform and Escherichia coli microorganisms is provided. The device comprises a water-impermeable first sheet; a water-impermeable second sheet attached to the first sheet; a dry, rehydratable culture medium comprising a lactose-fermentation indicator system, a β-D-glucuronidase indicator system that comprises a plurality of compounds that enhance β-glucuronidase enzyme activity in E. coli, a redox indicator system and a first cold-water soluble gelling agent adhered to the first sheet, the culture medium disposed in a microbial growth zone; and a second cold-water-soluble gelling agent adhered to the second sheet. The microbial growth zone is disposed between the first sheet and the second sheet. Methods of using the device are also provided.

The disclosure is directed at a system and method for rapid detection of low level bacteria in a growth medium. The method is directed at a two-stage process whereby a growth medium is incubated along with a first test formulation component for a predetermined period of time. After the incubation period, a second test formulation component is added to the growth medium to determine if there is a bacteria in the growth medium.

A thin film culture device for detecting aerobic bacteria in a sample is provided. The culture device comprises a self-supporting substrate sheet having a first major surface and a second major surface; a cover sheet attached to the substrate sheet, a sample-receiving zone disposed between the substrate sheet and the cover sheet, a first layer comprising a substantially dry, cold-water-soluble first hydrogel-forming composition adhered to a portion of the sample-receiving zone; and a plurality of indicator agents disposed in at least one layer adhered to the substrate sheet or the cover sheet. The plurality of indicator agents comprises three indicator agents for detecting distinct glycosidase enzyme activities, an indicator agent for detecting an alkyl esterase enzyme activity, an indicator agent for detecting a phosphatase enzyme activity, and a redox indicator. A method of using the culture device is also provided.

A thin film culture device for detecting aerobic bacteria in a sample is provided. The culture device comprises a self-supporting substrate sheet having a first major surface and a second major surface; a cover sheet attached to the substrate sheet, a sample-receiving zone disposed between the substrate sheet and the cover sheet, a first layer comprising a substantially dry, cold-water-soluble first hydrogel-forming composition adhered to a portion of the sample-receiving zone; and a plurality of indicator agents disposed in at least one layer adhered to the substrate sheet or the cover sheet. The plurality of indicator agents comprises three indicator agents for detecting distinct glycosidase enzyme activities, an indicator agent for detecting an alkyl esterase enzyme activity, an indicator agent for detecting a phosphatase enzyme activity, and a redox indicator. A method of using the culture device is also provided.

Provided is means for detecting Listeria monocytogenes and/or Listeria ivanovii in a simple and specific manner. A culture medium for detection of Listeria monocytogenes and/or Listeria ivanovii, provided containing the following components (A), (B), and (C): (A) a chromogenic substance which develops a color when decomposed by -glucosidase or a fluorogenic substance which develops a fluorescence when decomposed by -glucosidase; (B) a chromogenic substance which develops a color when decomposed by phosphatidyl inositol-specific phospholipase C or a fluorogenic substance which develops a fluorescence when decomposed by phosphatidyl inositol-specific phospholipase C; and (C) a sugar.

Disclosed is a microfluidic paper chip for detecting a microorganism, a method for preparing the same and a method for detecting the microorganism using the same. The microfluidic paper chip includes a lysis layer and a chromogenic layer which are laminated in this order. The lysis layer is composed of a hydrophilic paper containing a lysis reagent composition and the chromogenic layer is composed of a hydrophilic paper containing a chromogenic reagent.

A device for differentially enumerating colonies of coliform and Escherichia coli microorganisms is provided. The device comprises a water-impermeable first sheet; a water-impermeable second sheet attached to the first sheet; a dry, rehydratable culture medium comprising a lactose-fermentation indicator system, a -D-glucuronidase indicator system that comprises a plurality of compounds that enhance -glucuronidase enzyme activity in E. coli, a redox indicator system and a first cold-water soluble gelling agent adhered to the first sheet, the culture medium disposed in a microbial growth zone; and a second cold-water-soluble gelling agent adhered to the second sheet. The microbial growth zone is disposed between the first sheet and the second sheet. Methods of using the device are also provided.

A device for differentially enumerating colonies of coliform and Escherichia coli microorganisms is provided. The device comprises a water-impermeable first sheet; a water-impermeable second sheet attached to the first sheet; a dry, rehydratable culture medium comprising a lactose-fermentation indicator system, a -D-glucuronidase indicator system, and a first cold-water soluble gelling agent adhered to the first sheet, the culture medium disposed in a microbial growth zone; and a second cold-water-soluble gelling agent adhered to the second sheet. The microbial growth zone is disposed between the first sheet and the second sheet. The first sheet and second sheet are configured to retard passage of carbon dioxide therethrough. Methods of using the device are also provided.