Listeria Environmental Monitoring programs: Getting into the details

Transcription

1 Listeria Environmental Monitoring programs: Getting into the details Martin Wiedmann Department of Food Science Cornell University, Ithaca, NY Phone: Thank you to Drs. John Butts and Laura Strawn for pictures and helpful discussions

2 No. outbreaks Listeria Outbreaks and Incidence, Outbreak Incidence Incidence (per million pop) Era Outbreaks per year Median cases per outbreak Pre-PulseNet Early PulseNet Listeria Initiative WGS Data are preliminary and subject to change

3 Take home messages The processing plant environment is an important source of Listeria monocytogenes Environmental sources are a concern even for products without a CCP that controls L. monocytogenes found in raw materials Good environmental monitoring programs plans are set up to find pathogens, not to show that there are no problems If it s there and you don t find it, FDA likely will Environmental monitoring programs are much more complex and difficult to design and implement than finished product testing Programs are not one-size fits all and need to be designed individually for each facility Sampling will not control food safety hazards, the actions taken after positive results will Positive results need to be followed up with root cause analysis Results need to be used for immediate corrective actions as well as long term improvements (equipment design etc.)

4 Outline Background: How does Listeria survive and move in processing facilities Why to test and purpose of testing Environmental monitoring programs - When, where, and how? Follow up and corrective and preventive actions

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7 Outline Background: How does Listeria survive and move in processing facilities Why to test and purpose of testing Environmental monitoring programs - When, where, and how? Follow up and corrective and preventive actions

8 Pathogen Environmental Monitoring Programs the big picture Classical environmental monitoring program to verify control Increasingly being replaced with programs that include Traditional Verification sampling Process Control Investigative sampling (e.g., investigations to measure effectiveness of sanitation methods) Indicator Sites (includes sites close to a known risk area and Post Rinse Sites of both equipment and facility)

9 Listeria Equation (Environmental pathogen and spoilage equation) Controlled Traffic Patterns + GMP s + Sanitary Design Equip & Building + Clean Dry Uncracked Floors + Effective Sanitation Procedures = Listeria Control (Environmental pathogen and spoilage control)

10 HACCP lessons learned Foodborne disease outbreaks and finished product contamination events linked to facilities with HACCP plans Issues often with pre-requisite programs Pre-requisite programs often were lacking monitoring, documentation, verification and validation Need to focus on and strengthen pre-requisite programs Food Safety Modernization Act

11 FSMA Preventive controls These measures are required to ensure that hazards requiring a preventive control will be minimized or prevented. They include Process controls (traditional CCPs, for example pasteurization) Food allergen Sanitation controls Supply-chain controls Recall plan.

12 Oversight and management of preventive controls Monitoring Corrective actions and corrections Verification

13 Verification activities Product testing and environmental monitoring are possible verification activities Only required as appropriate to the food, facility, nature of the preventive control, and the role of that control in the facility s food safety system. Environmental monitoring generally would be required if contamination of a ready-to-eat food with an environmental pathogen is a hazard requiring a preventive control

14 FSMA and Environmental Monitoring Purpose Verify the effectiveness of sanitation programs Verify that hygienic zoning is working to: Protect product from cross-contamination or recontamination Prevent microbial harborage Understand normal environmental conditions vs. something has changed or something unusual is going on Not a specific preventive control, though records are required for a food safety plan Must be tailored to each facility May include pathogens or indicator organisms A useful program diligently tries to find the organism Adapted from Food Safety Preventive Controls Alliance

15 Goals of a microbial environmental monitoring program Verification sampling : Verify food safety procedures, such as Cleaning Sanitation Sanitary equipment design Hygienic zoning Preventive Control Investigation Identify problem areas harboring pathogen sources ( niches ) and locate potential contamination sources Characterize transmission pathways Validate (?) preventive controls (e.g., sanitation procedures for a specific piece of equipment) ( Seek and destroy investigation ) Early Warning that will predict potential loss of control ( Indicator sites ) Indicators sites are typically in zone 3 and 4

16 Outline Background: How does Listeria survive and move in processing facilities Why to test and purpose of testing Environmental monitoring programs - When, where, and how? Follow up and corrective and preventive actions

17 Designing environmental sampling plans general points Effective environmental sampling plans can prevent food contamination before it occurs Sampling plans need to be developed individually for each plant Layout, production schedules, facility design For many products Listeria and Salmonella as key targets Environmental sampling for other pathogens and spoilage organisms may also be relevant For verification testing that targets Listeria or pathogens, follow-up corrective and preventive actions need to be clearly defined (in writing)

18 Where to test the zone concept 18

19 Examples of zones Zone 1 (direct food contact surface) Zone 4 (outside) Zone 3 (floor) Zone 2 (outside surface)

20 Where to test Niches: Hollow rollers, table legs, etc.; floor wall junctures; floor cracks; difficult to clean areas; seals on doors, etc. Sampling of niches more likely to identify source Transfer points: Hands, door handles, floor, pallet jacks, trash cans Sampling of transfer points requires follow up to identify source Some areas could be both Key boards verification sites and indicator sites

21 Other sampling consideration Must select samples to find positives Subtleties of sampling are much more important with environmental samples as compared to finished product samples Need to set up a system that encourages collection of samples that yield positive results

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23 Where to sample if Our company goal for 2016 is zero Listeria environmental positives Our company pays a bonus if facilities have <1% Listeria positive samples (Food Safety KPI)

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33 When to test?

34 Production Dry clean Break Disassemble Rinse Production Foam Verify Control Break Production Break Production Break When to Sample? Sampling Objective Effectiveness of Sanitation Production Setup Sanitize Inspect Looking for LS Rinse Growth Niches Sanitize Break Assemble 34

35 When to test? Pre-op Less likely to yield positive samples More easy to interpret, will identify sanitation weaknesses Mid-op: in some countries testing must occur at least 4 h after start of production (new FDA draft guidance takes a similar approach) More likely to yield positive; good approach for verification Sample site positive may not be the site where the pathogen survives Positive sites typically will require pre-op follow-up sampling to identify pathogen source/niche Post rinse before soap: Seek and destroy, identify growth niches

36 When to test - days All days need to have similar likelihood of being samples Gold standard is use of random number generators to select days (and shifts if only one shift a day is sampled) A computer picks the day when sampling occurs: random sampling People pick ad-hoc when to sample: convenient sampling (even though the results may look random) True random sampling is much better than convenient sampling Convenient sampling more likely to occur at less busy days, which also may have lower risk of food safety issues

37 How often to test? Can range from daily/multiple times a day to weekly or maybe even monthly (in very small operations) Sites are typically pre-determined, but may be randomly rotated so that not all sites are sampled every times For example, only 50 of 100 predetermined sites may be sampled every time (sampling with replacement may be preferred) A set of high priority sites may be sampled every time Sampling frequency and sample numbers should be determined through a risk-based approach 1 sample for every 100 m 2 recommended by some

38 How to collect samples Different approaches for different tests

39 How to collect samples Sterile sampling techniques (sponges with gloves or handles) For pathogen sampling sponges are typically used rarely use swabs, only for very difficult to reach areas

40 Test methods Traditional methods: Often time consuming With traditional methods Listeria spp. testing is faster than L. monocytogenes testing Detection of surface molecules and other antigens Antibody-based methods (e.g., ELISA) Recombinant phage protein Nucleic acid amplification methods Polymerase chain reaction (PCR) Other nucleic acid amplification methods

41 Other testing methods Index organisms: commonly defined as markers whose presence relates to the possible occurrence of ecologically similar pathogens (e.g., Listeria spp.) Indicator organisms: commonly defined as markers whose presence relates to the general microbiological condition of the food or environment (i.e., hygienic quality) (e.g., coliforms, Enterobacteriaceae, SPC) ATP testing: rapid test for presence of organic material determines relative cleanliness of the surface monitors cleaning; requires at least 1,000 bacteria for a positive test

42 How do you know your sampling plan is Plant ID working? Prevalence data for 7 cheese plants routine sampling Prevalence (from routine) A 5.1% (34/664) E 11% (88/795) F <0.3% (0/334) G 9.1% (19/209) H 23% (24/106) I 0.4% (1/222) J 0.9% (1/106)

43 Validation of the sampling plan Completed after min. 6 months of sampling Routine sampling under supervision Additional sample sites performed by individuals with experience in environmental sampling who did not take the routine samples Sites were selected from zones 2-4

44 Validation results Plant ID Prevalence (from routine) Prevalence (from validation ) A 5.1% (34/664) 1.3% (2/150) E 11% (88/795) 10% (6/60) F <0.3% (0/334) 6.0% (3/50) G 9.1% (19/209) 2.4% (2/85) H 23% (24/106) 4% (2/50) I 0.4% (1/222) <2.0% (0/50) J 0.9% (1/106) 14% (7/50)

45 Outline Background: How does Listeria survive and move in processing facilities Why to test and purpose of testing Environmental monitoring programs - When, where, and how? Follow up and corrective and preventive actions

46 What to do with testing results Review testing results every time results are reported This should include review of at least last 4-8 sampling results to identify trends (e.g., site that has positives with intervening negatives) Take corrections on each positive sample and document action Organize testing results in one location (folder, three-ring binder or ideally electronically) Include documentation of corrections in same location Conduct regular (quarterly, yearly; depends on testing frequency & volume) review of testing results Tabulate and evaluate long-term trends

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48 06/29 07/13 07/27 08/10 08/24 09/08 09/21 10/05 10/19 11/02 11/16 11/30 12/14 12/28 01/11 01/25 02/08 02/22 2/28 03/14 03/28 04/11 04/25 05/09 05/23 06/06 % Lss+ Area Environmentals 100% 80% 60% 40% 20% 0% Date Identify trends in a given area or common location Determine overall effectiveness (%Listeria species or Listeria like free) 48

49 Guidelines for Corrective and Preventive Actions Corrections based on positive samples need to be plant specific and may differ by zone Positive samples should be followed up with additional investigations and root cause analyses beyond vector swabbing Deep cleaning is conducted in-conjunction with the Seek & Destroy Process as equipment parts are cleaned and sanitized followed by in intervention heat treatment to assure elimination of the contaminate. Preventive actions must go beyond deep cleaning and may include: Cleaning and sanitation procedures and SSOPs may need to be changed Master sanitation schedule may need to be revised and updated; cleaning and sanitation frequencies may need to be adjusted Maintenance may be needed and preventive maintenance program may need to be improved Equipment may have to be modified and/or replaced Level of daily and periodic disassembly modified

50 Correction Plan for small dairy plant: Flow Chart for Zone 3 & 4 Pre-operational sites in pilot plant area swabbed each month for Listeria spp. Drop additional site from monthly testing. Make report of findings. Audit area as necessary. Positive Add Notes to final report of investigation and any action taken. Evaluate site for possible contamination sources, niches, and transfer pathways. Perform investigative sampling before additional cleaning and sanitizing. Focused cleaning & sanitizing at positive site. Negative Positive 2 consecutive monthly Negative samples Positive Create an isolation area at positive site and cease use of area until 3 consecutive negatives Apply interventions as appropriate to assure transient and fixed equipment is eliminated as a source after investigative sampling. Continue daily sampling. Add additional site from contamination query to consecutive monthly testing Negative Positive Perform extra cleaning and conc. sanitizing. Retest after confirmation with plant manager that proper clean-up has been achieved. Identify and record at least 5 further vector sites for sampling. Sample additional sites pre-operational.

51 Root cause analysis how to make sure the same problem does not happen again From:

52 Fishbone diagram From

53 The frequency for Non-daily scheduled sanitation tasks to disassemble and clean mating surfaces must be established Provided by John Butts

54 Hollow pulley Solid pulley From This Previous Design To This Sanitary Redesign Provided by John Butts

55 From This Previous Design To This Sanitary Redesign Provided by John Butts

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57 Scheduled disassembly and cleaning required Provided by John Butts

58 Some Possible Action items Make sure business risks due to food safety (and specifically L. monocytogenes) issues are known and communicated in your company Make sure your company s leadership shows commitment to food safety and does not unintentionally send the wrong messages Assure that your company has a robust pathogen and microbial environmental monitoring programs that drive both short term corrective actions and long term improvements Review sampling plans Develop strategy to validate your sampling plans Assure that you use sampling results to drive short term and long term changes If you have a classical environmental monitoring program, consider reorganizing sampling into a Verification Monitoring Program, Preventive Control Investigations, and indicator sites