Environmental swab testing is performed to support foodborne illness outbreaks and investigations. This section provides information for public health inspectors (PHIs) when submitting environmental swabs to Public Health Ontario laboratory (PHOL) for testing.
PHOL performs microbiological testing of environmental swabs to support foodborne outbreak investigations or for R.R.O. 1990, Reg. 562: Food Premises, Section 80 as outlined below.
The standard plate count from a multi-service article shall not exceed 100 bacterialcolonies after cleaning and sanitizing and prior to re-use when tested by an officialmethod in accordance with the standard plate test, utilizing the swab technique.R.R.O. 1990, O. Reg. 562, s. 80
Standard Plate Count (SPC) results are obtained from the Aerobic Colony Count (ACC) methodperformed by PHOL. SPC and ACC are name variations of the same test method.
Environmental swabs processed during foodborne outbreak investigations will be tested for thepresence or absence of a specified clinically confirmed bacterial pathogen from a physical environment(e.g., cutting board, meat slicer, etc.).
Sampling instructions for environmental swabs are provided below. Test information including testingfrequency, turnaround times and reporting limits, is dependent on the specific analysis.Click on individual testing links for test directory details:
Instruction for sample selection of sanitation swabs:
Select items (e.g., cup, plate and/or utensils) for testing of a typical sanitation cycle run (i.e., routine cycle on dishwasher) or surfaces.
Instruction for sample selection of swabs for an outbreak investigation:
To identify the source of the pathogen, selection of sampling sites for the investigation should be informed by environmental and epidemiological factors. Random sampling may delay the identification of the source of the outbreak. Samples deemed as most likely to be positive should be sampled and submitted first.
PHOL should be notified prior to sample submission to allow for preparation of materials required for testing. Please contact the laboratory by calling PHOL Customer Service Centre at 416-235-6556 or toll free 1-877-604-4567.
The following steps are recommended to organize and minimize sample collection time:
The accuracy of the test results may be affected by improper collection, handling and/or shipping. Swab samples that do not meet the acceptance criteria may be rejected by the laboratory and a new sample may be re-submitted with a newly completed requisition. The acceptance criteria are outlined below.
The following tables outline the reporting limits and interpretation of the environmental swab analyses.Information such as collection conditions, time and date, and sanitation details should be consideredwhen interpreting swab results.
< 10 to > 2.0 x 103
High Aerobic Colony Count on the article or surface indicates inadequate sanitation. According to R.R.O. 1990, Reg. 562: Food Premises , Section 80, the standard plate count from a multi-service article shall not exceed 100 bacterial colonies after cleaning and sanitizing and prior to re-use when tested by an official method in accordance with the standard plate test, utilizing the swab technique.8
Foodborne pathogens should not be detected from a ready-to-eat food preparation surface swab andwould indicate poor food handling, inadequate work surface sanitation practices or possiblecontamination from an ill food handler. Appendix C: Major Foodborne Diseases: General Featuresprovide additional information regarding the organisms incubation period, clinical symptoms, mode oftransmission and associated foods.
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