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Missouri Produce Growers


Londa Nwadike
University of Missouri
Food Safety, Nutrition, Health & Physical Activity
(816) 482-5860

Free microbial water testing for Missouri produce growers

Londa Nwadike
University of Missouri
(816) 482-5860

Published: February 17, 2020

glass tubes with clear liquid

As noted in the previous edition of this newsletter, the microbial quality of the water that you are using pre-harvest, as well as post-harvest is very important to the safety of your produce. In order to know the quality of the water you are using, the water must be tested regularly. Growers using municipal (rural or city) water can utilize the annual test results from the municipal water source, but for growers using ground or surface water, testing is essential. The Food Safety Modernization Act (FSMA) Produce Safety Rule (PSR) requires produce growers to develop a microbial water quality profile (MWQP) of their agricultural water source(s) over time and Good Agricultural Practices (GAPs) auditors also require water testing. Importantly, knowing the quality of your water can help to provide a safer product to customers.

Therefore, the University of Missouri and Kansas State University Extension are continuing to provide free microbial water testing to produce growers, through a second grant from USDA. Through this new grant, MO produce growers can now get their water sources used for produce (both pre- and post-harvest) tested through your local public health department for free. Note that this free testing program will last until at least December 31, 2020.

Growers can go to your local (usually county) health department to ask for a bacteriology private water testing kit, which will include a sample bottle and submission form. If growers are planning to test more than one water source, they can ask for as many bottles as the number of different water sources they will test. In order to get the free testing, growers need to fill out the form as indicated in this article. Here is an example of how growers might fill out the form.

In the "Test requested" section at the top of the form, growers should select "other" and write "MPN for produce" in that line. MPN stands for Most Probable Number, which is the type of numerical test result that you will need. Please fill out the form completely and if you are testing a surface water sample, please write in "pond" or "creek" or the type of surface water you are testing in the "other" line of the "construction type" section toward the bottom of the form. Also mark "no charge routine well" in the "Test Requested" section. In the "No Charge Justification" section at the bottom of the form, mark "USDA/Non USDA inspected facility" to ensure that you do not need to pay for the test.

Further instructions on how to collect water samples for this free testing include:

  1. Label collection bottle with your name, sample identity (i.e. west well, north pond, etc), and the date it was collected.
  2. Wash hands thoroughly with soap and warm water. Gloves are not required but are a good practice.
  3. If using a water sampling stick for surface water (such as a pond), attach the provided water sample bottle onto it.
  4. Remove the lid from the container with care to not touch the inside of the container or lid. Do not rinse the sample container. There will be a white powder in each bottle which is needed for testing purposes.
  5. For a surface water source, dip the sample bottle down to a depth of 6-12 inches.
  6. For well water, run the pump for a few minutes to make sure the water in the well riser is not sampled. Make sure the sample represents the current well water.
  7. Fill the water a little past the 100mL fill line on the bottle.
  8. Cap the sample container, again with care to not touch the inside of the lid or container.
  9. Ensure that the labeling remained on the bottle, as described above.
  10. Place the sample bottle inside a sealable plastic bag and bring to your local public health department (generally Monday-Thursday, 8AM-4PM) within 24 hours of collection of the sample.


You will receive the test results within approximately one week of the sample arriving at the laboratory and will include the level of generic E.coli and total coliforms. The sample analysis results will also be shared with MU Extension and the Missouri Department of Agriculture only for research and educational purposes, but will not be shared or used in other ways.

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REVISED: February 17, 2020