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Archived - Follow up Guidelines for Fresh Fruits and Vegetables When Listeria is Detected in End Product and/or In the Environment

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This page was archived due to the coming into force of the Safe Food for Canadians Regulations. Archived information is provided for reference, research or record-keeping purposes only. It is not subject to the Government of Canada Web Standards and has not been altered or updated since it was archived. For current information visit Food.

June 2012


The purpose of these Guidelines is to provide inspection staff with guidance for conducting follow-up activities in response to the detection of Listeria monocytogenes in a fresh-cut fruit or vegetable (imported or domestic) or the repetitive detection of Listeria spp. in an establishment's environment. These Guidelines could also be used during follow-up activities when Listeria monocytogenes is detected in whole fresh produce, e.g. through sampling conducted by Other Government Departments.

A follow-up is conducted to verify a company's compliance with the applicable legislation and regulatory requirements under the Food and Drugs Act (Sections 4.(1) & 7) and Fresh Fruit and Vegetable Regulations (Part I.1, Section 3.1).

Scope of the Follow-Up

Follow-up activities are conducted when an issue has been transferred to the Canadian Food Inspection Agency (CFIA) Fresh Fruit and Vegetable and/or Imported and Manufactured Food Programs, in response to the reporting of a positive result for Listeria monocytogenes (including repeated findings of Listeria spp. in the establishment environment). Most often, the follow-up will commence after the CFIA food safety investigation and/or recall is completed although this is not always the case (e.g., the result of analysis of a sample is unsatisfactory but the product is not in distribution, or a sample is assessed by the laboratory as an investigative result).

Roles and Responsibilities

CFIA is responsible for following up on the detection of Listeria monocytogenes in fresh fruit and vegetables, like any other potential food safety issue. Collaboration between the CFIA Imported and Manufactured Food and Fresh Fruit and Vegetables inspectors is encouraged during follow-up activities, where appropriate.

Follow-Up Guidelines

When planning your follow-up activities, take into consideration the nature of concern e.g., Category 1 product, Category 2 product, product distributed to population at risk, etc. since this will determine the level of priority and oversight required (as per the 2011 Health Canada Policy on Listeria monocytogenes in Ready-to-Eat Foods (Listeria policy), section 6).

Inspection staff should initiate follow-up procedures, as outlined below (as applicable).
N.B.: Some information may have been previously gathered and activities already conducted during a food safety investigation.

1. Plan and prepare for the follow-up, i.e., refresh your knowledge about Listeria monocytogenes, review appropriate reference documents (refer to the reference list developed for the Listeria Policy Update: Oversight Activities for fresh fruit and vegetables training), review previous good manufacturing practices (GMP) inspection reports, review company profile and previous complaints (i.e., Issue Management System (IMS)), consult with Supervisor/Regional Program Officer/Area Program Specialist. Create or update the IMS file to track all activities related to the follow-up. Make sure to record all observations and results during the course of the follow-up in IMS.

2. Notify the company immediately of Listeria monocytogenes or Listeria spp. detection, as the case may be.

3. Determine if the implicated product(s) have been distributed and if yes, prevent their further distribution. If there is a concern that the implicated product(s) are in distribution, contact your Supervisor and the Area Recall Coordinator (ARC). Refer to the Food Investigation Response Manual for further information.

4. Educate the company on the Listeria policy. If the representative of the company is not familiar with the Listeria policy, be sure to leave a copy at the time of the visit and/or provide the web link to the policy.

5. Conduct an on-site inspection at domestic establishments, in order to evaluate the company's Listeria control. For importers, request supportive documentation to assess importer and foreign manufacturer Listeria control. Follow-up with domestic establishments and importers should include, but not restricted to, a review of the following (as applicable):

N.B.: Inspection staff may want to consult the General Principles of Food Hygiene, Composition and Labelling (GPFHCL), Good Importing Practices for Food (GIP) and/or the Fresh Fruit and Vegetable Establishment Inspection Task list to help guide the follow-up activities.

6. Request that the company takes immediate corrective action and submits a Corrective Action Plan (CAP) to CFIA within a reasonable timeframe (i.e., 5 working days). The CAP demonstrates that the company is committed to implementing control measures to address the presence of Listeria.

The CAP should include:

  1. Description of the problem
  2. Person(s) responsible for the CAP.
  3. Description of immediate/short term corrective measures and their respective timelines, including:
    • Action that will be taken or has been taken on the product found unsatisfactory for the presence of Listeria monocytogenes (e.g., disposal, recall, etc.);
    • Implementation of an intensive cleaning and sanitation plan and procedures (e.g. dismantling equipment and clean out of place, etc.)
  4. Identification of root cause(s), including:
    • Review of programs such as, sanitation, equipment maintenance, personnel training, GMPs/HACCP, etc.;
    • Verification that no other product is affected;
    • Enhanced sampling plan for end product and environment Food Contact Surfaces (FCS) and Non-FCS (NFCS);
      Note: The purpose of the enhanced sampling is to try to identify source(s) of contamination and verify the effectiveness of the company's corrective actions. The enhanced sampling plan should include but is not restricted to:
      • Environmental sampling of FCS and/or NFCS. The FCS sampling should target the implicated production line of the establishment.
      • End product sampling should be linked to environmental sampling (e.g., take sample of product lot produced on the production line sampled for FCS). Companies should consider product hold-and-test procedures, as per the Listeria policy, Figures 1 and 2.
  5. Description of preventative measures, including:
    • Sanitation program intensified;
    • Other measures as determined by the root cause analysis.
  6. Description of activities planned to verify the effectiveness of preventative measures.
    • Implementation or revision of the monitoring sampling plan for product and environment;

For further details on each element of a CAP, refer to the document entitled Elements of an Acceptable Corrective Action Plan (CAP) Following a Listeria Finding. Industry can access the Food Safety Enhancement Program Manual (FSEP).

7. Communicate to the company that they can resume routine monitoring activities once they have completed the following (as per the Listeria policy):

The number and location of FCS samples of the enhanced sampling plan should be adequate, including at least the FCS sites of the routine sampling program, in order to ensure that the production line is negative and under control (Listeria policy, Figures 1 and 2, and footnotes a & f).

According to the Listeria policy (section 7 and Annexe A), repetitive findings of FCS with any Listeria spp. in the establishment environment could be an indication of inadequate GMPs and sanitation practices. If two or more FCS samples from the same production line are found positive within a short timeframe, this is considered to be persistent contamination. In the event of persistent contamination, the establishment must reassess their corrective action plan to ensure its efficacy.

Note: The analysis of samples should be conducted by an accredited lab (listed under the Standard Council of Canada and the Canadian Association for Laboratory Accreditation Inc. websites) using a method published in the Health Canada Compendium of Analytical Methods for Listeria in which the application section is appropriate for the intended purpose. Sample sites should be analysed individually.

8. Review the company's CAP for acceptability in consultation with your Supervisor, Regional Program Officer and/or Area Program Specialist. Inspectors are encouraged to work with the company to educate them on their responsibilities under the Listeria policy and the need for them to implement effective controls. Notify the company immediately in writing if the CAP is not received in a timely manner or if it is not acceptable.

9. For domestic companies, conduct an on-site verification inspection to ensure that the corrective actions have been implemented by the company. For importers, obtain documents (e.g., results of enhanced environmental and product sampling, intensified sanitation plan) that can assist to determine that corrective actions are implemented and are effective at controlling the hazard.

In order to verify that the corrective actions implemented have been effective at controlling the hazard, the CFIA may conduct sampling. Domestic companies may be subject to both end product and/or environmental sampling. For importers only end product samples can be taken. Sampling will be assessed in consultation with Program on a case-by-case basis and may include:


Note: FCS samples should be linked to end product samples to ensure that the production line is under control (Listeria policy, Figures 1 and 2). Consult Appendix 1 of this document for more details concerning procedures on environmental sampling techniques.


Repetitive Listeria findings may increase the level of CFIA oversight (frequency of inspections, sampling, etc.) Notify your Supervisor, Regional Program Officer and/or Program Specialist of any repetitive findings in order to determine next steps.

10. Once the CAP has been determined to be effective at controlling the hazard, the company can return to routine activities. Update and close the IMS file once the issue is resolved.


Fresh Fruit and Vegetable Regulations
Food and Drugs Act
Food and Drug Regulations
Policy on Listeria monocytogenes in Ready-to-Eat Foods
Food Safety Enhancement Program Manual

Appendix I


Environmental sampling is an important verification tool for assessing trends as well as the source, and dispersion of any microbiological contamination in food establishments. One microbial pathogen of concern in the food industry is Listeria monocytogenes. Listeria spp. is widely distributed in nature and hence, could be present in processing environments and lead to a serious concern for industry. Presence of Listeria monocytogenes in food products has resulted in outbreak situations, product recalls, and destruction of contaminated product, extensive sanitation procedures and major financial losses for food producers. Environmental sampling and testing for Listeria in the processing environment can permit earlier identification of any potential persistent contamination and provide an increased ability to identify and protect against Listeria monocytogenes contamination of the finished products.

Listeria monocytogenes is a gram-positive, non-sporeforming facultative anaerobic rod bacterium which grows between -0.4 and 45°C. This microorganism has been isolated from plant, soil, and surface water samples, and has also been found in silage, sewage, milk of healthy cows or suffering from mastitis, and human and animal feces. Listeriosis can manifest itself in two different forms, namely, invasive and non-invasive. Invasive listeriosis typically occurs in people with weakened immune systems (e.g. patients with AIDS, cancer patients, elderly, etc.), while non-invasive listeriosis can occur in anyone if large enough numbers of bacteria are consumed (e.g., >1000 cfu/g). This elevated degree of severity among populations at risk highlights the importance of minimizing exposure of Ready to Eat (RTE) foods to Listeria monocytogenes contamination.

Environmental testing provides an opportunity to identify problems before they lead to finished product contamination, potential health risk to consumers or product recalls.

The 2008 Canadian listeriosis outbreak linked to RTE meat products and the subsequent Investigator's Report (Weatherill Report) resulted in the recommendation that Health Canada revise its 2004 Policy on Listeria monocytogenes in Ready to Eat food to update and clarify its position with respect to all high risk RTE foods. In summary, the revised 2011 HC policy (Listeria policy) recommends to adhere to practices that are aimed at reducing the risk of Listeria monocytogenes contamination in establishments as well as in products. This 2011 revised Listeria policy has categorized RTE foods into two categories based upon health risk.

Category 1 RTE foods are:

Category 2A RTE foods are those which are known to support the growth of Listeria monocytogenes to levels no greater than 100 cfu/g throughout the stated shelf-life, do not have a kill step, and for which validation studies are required. If the stated shelf life of the product is ≤ 5 days, no validation is needed.

Category 2B RTE foods are those in which the growth of Listeria monocytogenes cannot occur throughout the stated shelf-life (i.e., a RTE food in which Listeria monocytogenes does not increase in numbers by 0.5 log cfu/g or greater throughout the stated shelf-life) and for which validation studies are required. Validation studies are not required for RTE foods that have a pH 4.4 regardless of aw, or aw < 0.92 regardless of pH, or a combination of pH < 5.0 and aw < 0.94, (in which cases no validation is needed).

Inspection Procedures for Environmental Sampling


Sanitizer – Food Grade Chemical (e.g. 70% Ethanol)

Environmental swab kits:

Preparation for Environmental Sampling

Prior to conducting a follow-up inspection where environmental/product sampling will be conducted, contact the establishment to communicate the upcoming inspection visit and to ensure that appropriate processing activities will be occurring at the time of inspection. Inspectors should verify that the best before date stated on the environmental kits has not been exceeded. Expired kits should not be used. It is also important to place gel packs from the kit into the freezer at least 24 hours before the sampling is going to be conducted.

Selection of Food Contact Surface (FCS) Sample Sites

Food contact surfaces are anywhere an exposed surface or object has direct contact with the unpackaged RTE product. For environmental sampling, select sites which are exposed to both the environment and the product or where there is a higher probability of RTE product contamination. Suggested FCS sites are:

The number of sampling sites will vary according to the complexity of the processing system or packaging line being sampled. Prior to sampling, survey the line to determine sites to be sampled, and document them on the Lab Sample Tracking System (LSTS) submission form. A 900 cm2 (30 cm x 30 cm or equivalent) surface should be swabbed whenever possible. Generally, surfaces should be swabbed after the start of the operations (the policy recommends approximately after 3 hrs of processing but if the duration is shorter than 3 hrs, swabbing can be done towards the end of the operations, e.g., 1-2 hrs into processing).

Environmental Sampling Techniques

Sampling using aseptic techniques must be used for all samples taken for microbiological purposes. It is a technique which uses sterile containers and equipment, including gloves, to prevent the introduction of any contamination from outside sources into either the product or sample taken.

When samples are taken under these conditions, it is assumed that the results of the analysis indicate the actual conditions under which the product was manufactured or handled. Cross-contamination caused by the person taking samples is avoided if proper procedures are followed. If Listeria monocytogenes is found in the unused or unopened sample, then it can be indicative that it was introduced during the manufacturing process and not by the sampler.

Environmental sampling kits are supplied by the operational centre. Ten pre-moistened swabs for sampling food contact surfaces are provided with each kit. Upon receipt of the kits and before taking samples, review the instructions on aseptic sampling techniques and the content list supplied with the kits. Report any problems with the sampling kits immediately to the Area Program Specialist. Avoid contaminating the materials from the sampling kit, the samples, the equipment or the product being sampled. If resources permit, it is recommended that the swabbing process be completed by two inspectors.

Use the following sampling techniques when taking the swabs:

  1. Label the Whirlpak® sample bags and record information regarding the sampling sites. Use a waterproof soft felt pen for labelling all bags and ensure that while writing you do not puncture the plastic bag.
  2. Place one of the freezer packs at the bottom of the Styrofoam box. Use newsprint or a similar material to prevent direct contact between the pack and the swabs to be sampled.
  3. Thoroughly wash and dry hands.
  4. Open the package containing the pre-moistened sterile swab but do not remove the swab. Put on the sterile gloves and remove the sterile swab from the package.
  5. Rub the swab firmly and thoroughly over the surface to be sampled, without lifting the swab. Swab the surface area up and down until the whole target surface is covered, i.e., 900 cm2 (see Figure A), then turn over the swab and swab the surface area from right to left until the whole target surface is covered (see Figure B).
    Figure A: Up and down motion covering
    30 cm by 30 cm surface area
    Diagram - Vertical Swabbing Technique. Description follows.
    Description for Vertical Swabbing Technique

    Diagram of the Vertical Swabbing Technique When Taking an Environmental Sample for Listeria

    The image shows how to swab by vertical motion when taking an environmental sample for Listeria. The surface area selected should be 30 cm by 30 cm and is swabbed up and down until the whole target surface is covered.

    Figure B: Right to left motion covering
    the same 30 cm by 30 cm surface area.
    Diagram - Horizontal Swabbing Technique. Description follows.
    Description for Horizontal Swabbing Technique

    Diagram of the Horizontal Swabbing Technique When Taking an Environmental Sample for Listeria

    The image shows how to swab by horizontal motion when taking an environmental sample for Listeria. The surface area selected should be 30 cm by 30 cm and is swabbed in a right to left motion until the whole target surface is covered.

    Note: For surfaces which are difficult to swab because of their contour (i.e. conveyor belts), it may not be possible to swab a defined area using the above procedure. In this case, swab the area to be sampled using the same technique described above (up and down/ left to right) and then turn over the swab and swab the surface area in a diagonal pattern, until 900 cm2 is covered in total (e.g. 20 cm x 45 cm). This allows the sampling of every plane of the surface that will likely come into contact with the food (see Figure C).

    Figure C: Swabbing of irregular surfaces – Up and down/right to left and diagonal motions.
    Diagram - Swabbing Technique. Description follows.
    Description for diagram of the Swabbing Technique

    Diagram of the Swabbing Technique When Taking an Environmental Sample for Listeria on Irregular Surfaces

    The image shows how to swab irregular surfaces when taking an environmental sample for Listeria. The surface area selected is swabbed up and down then right to left and then turn over the swab and swab the surface area in a diagonal pattern.

  6. Release the swab into the appropriately labelled Whirlpak® sample bag. Do not let the swab touch the outside of the bag.
  7. Seal the bag making sure not to contaminate the sample.
  8. Place the bag in the Styrofoam box.
  9. Sanitize the sample site using a 70% ethanol spray solution following environmental swabbing (Note: some establishments might want to perform their own FCS sanitation after CFIA swabbing).
  10. Change gloves for the next sampling site and complete swabbing all selected sites.
  11. Once all samples have been taken, place the sample in the middle of the Styrofoam box and use fillers to prevent the shifting of the samples during shipping and to prevent direct contact between the packs and the samples. Add the other freezer pack on top.
  12. Include a complete LSTS submission form inside an empty Whirlpak® bag. Seal and label the box.
  13. Send to the laboratory indicated in the sampling guidelines within 1 working day.

Environmental sampling is conducted under directed sampling plans and generally linked to the sampling of a finished product. When taking a product sample (consisting of 5 sample units) ensure that the product selected for sampling was produced on this specific line and was processed the same day that the production line was swabbed.


Policy on Listeria monocytogenes in Ready-to-Eat Foods
Health Canada, Compendium of Analytical Methods. MLFP-41

Note: The following documents are intended for internal use. CFIA staff can access these documents using the internal tools noted below.

Food Products Submission Form (LSTS Citrix program)
Training Manual for Microbiological Sampling (RDIMS 2105712)

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