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microbial diseases laboratory

Test Order Water Exam for Bacterial Contamination

Pre-Approval Required

Yes. CDPH and local health department submitters should discuss their testing needs with Foodborne & Waterborne Diseases Section management to determine whether service can be offered. A 1 week or more advance lab consultation is requested prior to sample collection, if possible. Samples received without prior authorization will not be tested until such authorization is obtained.

These tests are conducted to assist public health decision-making, regulatory actions, for reference purposes, and for emergency response support.

Supplemental Information

Samples must be received in the laboratory at least an hour before the transit limit. The transit limit for coliform tests is 30 hours and for the heterotrophic plate count test it is 8 hours from the time of collection.

Submission Form

1. Form "801 Request for Laboratory Services - Drinking and Recreational Water" and/or

2. A detailed list and description of items collected by the investigation team, ie. Environmental Health, Food and Drug, Drinking Water Program, etc

3. The submittal form(s) should be completed and secured in a water-tight bag and placed outside the secondary containment barrier but within the shipper box

Performed on Specimens From

Suspected water-related outbreak; trace-back surveillance; regulatory authorities.

Acceptable Sample/Specimen Type for Testing

Drinking and/or recreational water. A temperature control sample, labeled TC, should be collected and included in each box of samples to verify that holding temperatures remain between 4-10°C.

Minimum Volume Required

Coliform tests: 100 ml per method of analysis

Heterotrophic plate count: 100 ml

Bacterial pathogens: up to 10 Liters, consult with the laboratory

Storage & Preservation of Sample/Specimen Prior to Shipping

1. Sterile, leak-proof containers
2. Add a chlorine neutralizer if appropriate
3. Maintain samples at 4-10°C; do not freeze water samples


Refrigerated and room temperature samples should be transported at 4-10°C with cold packs.

Sample/Specimen Labeling

1. Submitter identification number that matches to a sample submittal form

2. Type of sample

3. Date and time collected

4. Collection point

Shipping Instructions which Include Specimen Handling Requirements

Follow approved packaging and shipping regulations for biological samples. Please label the outermost container(s) to clearly indicate the storage temperature. Ship to:

CA Department of Public Health
Microbial Diseases Laboratory
Specimen Receiving – Rm B106
Attention: MDL – Foodborne & Waterborne Diseases Section - water
850 Marina Bay Parkway
Richmond, CA 94804

Test Methodology

1. “Standard Methods” for coliforms and heterotrophic plate count
2. “Best practices” for bacterial pathogen detection

Turnaround Time

Varies with analyte and method.

Interferences & Limitations

Direct detection methodologies, such as polymerase chain reaction and enzyme or antibody based kits, may be invalidated due to interfering substances in the sample. Culture methods may be invalidated if there is heavy non-coliform growth present that obscures phenotypic reactions in tubed or plated media.

Additional Information

Water samples may be bulky and/or require large containers. To prevent contamination of other samples in the same shipper box, please follow the triple containment rule of thumb. Use absorbents under and between large liquid samples and/or enclose in water-tight bags. Glass containers need extra padding beneath and between containers. Add a layer of newspapers to shield the secondary container from direct contact with the cold packs.

MDL Points of Contact

MDL - Foodborne & Waterborne Diseases Section (510) 412-3796, Monday - Friday 8 AM to 5 PM PT

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