Water Analysis
Microbiological water analysis including tap, bottled, and mineral water is an essential element in ensuring water safety and absence of pathogenic bacteria that cause waterborne disease. Analysis of production water in food industry will help in minimizing contaminants level in final product. NAWAH laboratories has ISO/IEC 17025 accreditation in broad range of test method stated in European and Egyptian National Food Safety Authority (NFSA)regulation including:
- Heterotrophic Plate Count
- Enumeration of total coliform
- Enumeration of Thermotolerant Coliform
- Enumeration of E. coli
- Enumeration of fecal Streptococci/Enterococci
- Detection of salmonella spp.
- Enumeration of Staphylococcus aureus
- Enumeration of Pseudomonas aeruignosa
- Enumeration of Sulfite Reducing Bacteria
- Enumeration of Clostridium perfringens
1. Heterotrophic Plate Count
Heterotrophs are a group of microorganisms that use organic carbon as the main carbon source and are found in every type of water. Detecting heterotrophs in water is done by using a method called Heterotrophic Plate Count (HPC).
The test can be performed by different methods:
- Pour plate method.
- Spread plate method.
The test can be performed by using 2 different media:
- Plate Count Agar at 35.00 °C± 1.0 for 48 hrs. ± 2.0 hr.
- R2A Agar at 22.0 °C for 5 to 7 days
The test is performed in accordance with the latest edition of Standard Methods for Examination of water and Waste water (SMWW) as per Egyptian Ministry of Health regulation (Decree no. 458-2007).
2. Detection & Enumeration of Total Coliform
Total coliform bacteria include a wide range of aerobic and facultatively anaerobic, Gram-negative, non-spore-forming bacilli. Total coliforms include organisms that can survive and grow in water. Hence, they are not useful as an indicator of fecal pathogens, but they can be used to assess the cleanliness and integrity of distribution systems and the potential presence of biofilms.
The test is performed by Membrane Filtration Technique in accordance with the latest edition of Standard Methods for Examination of Water and Waste water (SMWW), as per Egyptian Ministry of Health regulation (Decree no. 458-2007).
The membrane filter technique uses a filtration apparatus and a cellulose filter of 0.45 µm pore size. A known Volume of a sample of water is passed through the filter, and the filter is then transferred to a bacteriological growth medium (m- Endo medium). Bacteria trapped in the filter grow on the medium and form colonies. By counting the colonies, an estimate can be made of the number of bacteria in the original sample.
3. Detection & Enumeration of Thermotolerant Coliform
Thermotolerant coliform bacteria (commonly referred to as fecal coliforms) are a subgroup of the Total coliform group, they appear in great quantities in human and animals wastes
The test is performed by Membrane Filtration Technique in accordance with the latest edition of Standard Methods for Examination of Water and Waste water (SMWW), as per Egyptian Ministry of Health regulation (Decree no. 458-2007).
The membrane filter technique uses a filtration apparatus and a cellulose filter of 0.45 µm pore size. A known volume of the water sample is passed through the filter, and the filter pad is then transferred to a bacteriological growth medium (m FC medium ). Bacteria trapped in the filter grow on the medium and form colonies. By counting the colonies, an estimate can be made of the number of bacteria in the original sample
4. Detection & Enumeration of E. coli
Escherichia coli is considered the most suitable indicator of fecal contamination.
Detection is performed by using media containing 4-methylumbel-liferyl–D-glucuronide (MUG).
E. coli produces β-D-glucuronidase enzyme that hydrolyzes the MUG substrate to produce a blue fluorescence.
The test is performed by Membrane Filtration Technique in accordance with the latest edition of Standard Methods for Examination of Water and Waste water (SMWW), as per Egyptian Ministry of Health regulation (Decree no. 458-2007).
5. Detection & Enumeration of Enterococci
Intestinal enterococci are a subgroup of the larger group of organisms defined as fecal streptococci, comprising species of the genus Streptococcus. These bacteria are Gram-positive and relatively tolerant of sodium chloride and alkaline pH levels.
The enterococci group can be used as an indicator of fecal pollution. Most species do not multiply in water environments.
Important advantages of this group are that they tend to survive longer in water environments than E. coli, are more resistant to drying, and are more resistant to chlorination.
Although enterococci are broadly used as an indicator of fecal pollution in water and are commonly found in the feces of humans and other warm-blooded animals, some species can persist and grow in the natural environment and do not appear to be related to fecal pollution.
The test is performed by Membrane Filtration Technique in accordance with the latest edition of Standard Methods for Examination of Water and Waste water (SMWW), as per Egyptian Ministry of Health regulation (Decree no. 458-2007).
The membrane filter technique uses a filtration apparatus and a cellulose filter of 0.45 µm pore size. A known volume of the water sample is passed through the filter, and the filter pad is then transferred to a bacteriological growth medium. Bacteria trapped in the filter grow on the medium and form colonies. By counting the colonies, an estimate can be made of the number of bacteria in the original sample
6. Detection of Salmonella spp.
The Presence or Absence of Salmonella is monitored in water where there is perceived to be a risk of infection.
Salmonella can be present in all types of domestic and agricultural waste water, freshwaters, including ground and drinking waters as well as seawater.
Pre-enrichment stage using a non-selective liquid medium (BPW) is needed to permit the detection of low numbers of salmonella or injured salmonella.
The test is performed in accordance with ISO 19250:2010
7. Detection & Enumeration of Staphylococcus aureus
The presence of Staphylococcus aureus in water is a concern because of its potential to cause human infection and also because of its multiple antimicrobial resistance.
The test is performed by single plate procedure method in accordance with the latest edition of Standard Methods for Examination of water and Waste water (SMWW).
Notes:
- Samples must be stored at temperatures below 8 °C (without freezing) during transit to the laboratory.
- Sample volume shall be at least 1 L, Except for Salmonella testing, as an additional 1.0 L will be needed.
- Samples must be in a sterile container with required preservatives (e.g., 0.9 ml of 3% sodium thiosulfate Na2S2O3 for each 1.0 L sample).
- Samples transportation is the client’s responsibility unless sampling is performed by NAWAH.
Reviews
There are no reviews yet.