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Turn Around Time and Results

  • Using the Colilert test for generic E. coli / coliforms results will be available after 24 + 2 hours. Laboratory results can be delivered via fax, email, or mail. All results should be kept in the food safety manual.
  • Based on risk assessment research, the recommended generic E. coli testing is as follows: For water not coming in direct contact with the edible portion of a plant:
    • Acceptance Criteria: Less than or equal to 126 MPN/100mL (geometric mean of 5 samples)
    • Acceptance Criteria: Less than or equal to 576 MPN/100mL (for any single sample)
  • For water coming in direct contact with the edible portion of a plant:
    • Acceptance Criteria: Less than or equal to 126 MPN/100mL (rolling geometric mean n=5)
    • Acceptance Criteria: Less than or equal to 235 MPN/100mL (for any single sample)
  • These standards were set for by the EPA as the Bacterial Water Quality Standards for Recreational Waters (EPA).
  • When results indicate high counts, a more aggressive sampling program (i.e., sampling once per week instead of once per month) should be instituted if an explanation for the contamination is not readily apparent. Do not use water from that water system, in a manner that directly contacts edible portions of the crop, until the water can meet the outlined acceptance criteria for this use.
Page Last Updated: 7 months ago
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