Bacteriological H2S field tst kit,w/bag

General Description:
Bacteriological field testing kit for drinking water using powder pillow with H2S test medium and a sterile whirl-pak type bag for testing of 20 ml (or 100 ml) water sample.

Technical Specifications:
This is a simple bacteriological testing kit that could be used to indicate the presence of pathogens. It will globally react on presence of (H2S - Hydrogen Sulfide Producing Bacteria’s like) Salmonella, Citrobacter, Proteus, Edwardsiella, and some species of Klebsiella in drinking water, surface water, and recreational waters. It does however not attempt to identify the specific pathogens.
The kit can be used with any water irrespective of its source, including chlorinated water.
The kit comprises a simple sterilized plastic bag of whirl-pak type and a powder pillow/sachet which contains dry powder medium.
The powder is completely soluble in water and a dark amber colour solution is formed on the addition of water. The solution will change colour to black in the presence of H2S producing organisms in ambient temperatures between 25ºC and 44ºC, preferably to be kept at 35-37ºC, for an observation time of 24 to 48 hours. No incubator is needed for this range of temperatures

The medium
With reference to the composition of UNICEF Catalogue Number S0000568, the composition of the medium powder can be as follows:

Bacteriological grade Peptone, Percent Range: 80,0 - 90,0
Potassium Phosphate, Dibasic, Percent Range: 15,0 - 25,0
Ferric Ammonium Citrate, Percent Range: 1,0 - 5,0
Sodium Thiosulfate, Percent Range: 1,0 - 5,0
Sodium Lauryl Sulfate, Percent Range: 0,5 - 3,0

The dry medium is in the form of brown to yellow homogeneous free flowing powder.
The pH of the aqueous 5% solution with distilled water ranges around 7.37 at 25ºC.
The powder must be prepared according to Good Manufacturing Process (GMP)

The bag:
The bag is a transparent Whirl-Pak type, Sterile sampling Bag.
The sample bag can be easily and securely closed e.g. with a tab folded over three times. Capacity is indicated on the bag with a fill line for 20 ml - or for 100 ml water sample. The bags must be suitable for the specific purpose, i.e. not contain any components that can interfere with or contaminate the potential test reaction. All bags are sterilized after manufacturing.

The standard kit size is for 20 ml sample size, bag and powder media in pillow.
As an alternative option a 100 ml bag and corresponding powder media (pillow) is available on request.

Shelf life of the medium and sterile bag to be of minimum 2 years.

Packaging and labelling:
The product does NOT contain any IARC listed chemicals.
Each kit is labeled with the name of the product, directions for use, name and address of the manufacturer, batch and code number, manufacturing and expiry dates and storage conditions. The labeling would normally contain a warning related to the result, such as example: 'If water turns black it is not safe for drinking. There is high risk that it is contaminated with pathogenic bacteria and faecal coliform. In such case, other more precise microbacteriological tests are required for verification before drinking the water untreated.'

Instructions for use:
The test is not to replace the conventional Presumptive Coliform test and other laboratory based tests, and the results should be treated with caution.
Problems that are likely to be encountered with these kits are false positive rather than false negative. In groundwater, there is a possibility of sulphides being present and giving positive results of H2S rather than the faecal contamination. Such misclassification of drinking water errs on the side of safety.
The kit is useful in educational and motivational campaigns to promote water sanitation and hygiene in outreach and dissemination programs.
The kit is used in regions where the ambient temperature ranges between 25ºC and 44ºC. The optimal incubation temperature would be 35-37ºC. The sample should be kept 24-48 hours where after it can be observed for potential colour change.
In cold climatic regions (where ambient temperature is below
25ºC) the kit should be used with an incubator.
The kits in their boxes should be stored in cool, dry place away from sunlight at room temperature of maximum 30ºC.

The kit could be used in routine testing of water quality as well as during epidemics of water borne diseases to find the source and spread of pollution.