The Role of Environmental Monitoring for Controlling Pathogens in Food Manufacturing Plants

Transcription

1 The Role of Environmental Monitoring for Controlling Pathogens in Food Manufacturing Plants A Presentation at the British Columbia Food Protection Association s Speakers s Evening February 24, 2004 Richmond, British Columbia Paul A. Hall, Ph.D. Sr. Director Microbiology and Food Safety Kraft Foods N.A. Glenview, IL

2 Producing Safe Food is our First Priority Consumer Protection & Trust Consumer trust Food Safety is critical to that trust Business Survival Our brands are most important assets Industry Responsibility Committed to food safety across the food chain Industry-wide agreement not to compete in the area of food safety

3 * Adapted from Sofos, et al., 1998 Methods to Reduce the Risk from Pathogens in Food* Prevent inadvertent contamination Inhibit growth Remove contamination

4 Top Line Summary Public health is best protected by control of Pathogens via: Aggressive environmental monitoring Effective corrective actions Proper equipment design Adherence to GMPs and SSOPs Proper handling practice Refrigerate perishable RTE products at <40 F (<4.40º C) Consume perishable RTE products quickly Appropriate intervention strategies Formulation (e.g. lactate salts/sodium diacetate) Post-packaging treatments

5 Pathogen Control Approaches/ Interventions HACCP and Prerequisite Programs Sanitation and GMP s Environmental Monitoring Program Ingredient Specifications Product Formulation Vendor Qualification & Quality Expectations Auditing and Certification Programs New Processing Technologies Improved Detection Methods Good Agricultural Practices/On-Farm Controls

6 Pathogen Control - Listeria monocytogenes as an Example Certain foods pose an increased risk of being associated with listeriosis These foods have the following properties: Have the potential for contamination with LM Support the growth of LM to high numbers Are ready-to to-eat foods Require refrigeration Stored for extended periods of time

7 Prevalence of Listeria monocytogenes * in Sliced Lunchmeats and Franks Percent Positive Sliced Lunchmeats Franks Year * FSIS Results of ready-to to-eat products analyzed for Listeria monocytogenes

8 Incidence of Foodborne Illness : Listeria* Incidence per 100,000 Population National Health Objective: *Preliminary FoodNet Data on the Incidence of Foodborne Illnesses --- Selected Sites, United States, 2002

9 Environmental Monitoring Prerequisite controls are the foundation upon which a solid HACCP program is built and include: GMP s Sanitation Practices Employee Training Equipment Design and Maintenance An effective monitoring program is a critical component to measuring the overall effectiveness of the microbiological controls that are in place. Use of proper indicator organisms or specific target pathogens depend upon the specific product/process/plant under consideration.

10 Environmental Monitoring Techniques Visual Inspection Direct Surface Testing Swab Sponge Contact Plate Rinse ATP Bioluminescence Air Sampling

11 Indicator Organisms What They Measure Potential presence of pathogens Faulty production or handling practices Insufficient thermal kill Insufficient cleaning and sanitation Inappropriate equipment or facility design Improper human handling Product recontamination Quality of a food or ingredient

12 Indicators Advantages Can identify microbial harborage points Are usually present more frequently that specific pathogens Are cost effective Can be used for developing trend analysis and statistical process control charts

13 Categories of Indicators Microbial numbers Aerobic Plate Count Direct Microscopic Count Metabolic products of microorganisms ATP ph Trimethylamine Specific microbial groups Total coliforms Total enterobacteriaceae Generic Escherichia coli Listeria species

14 Choice of Indicator The choice of a microbiological indicator depends on a number of considerations Type of product/process (e.g. wet/dry) History of food product (association with known pathogens) History of the plant environment Points in the process to be monitored Expected background flora Pre-op vs. operational monitoring Safety vs. spoilage Others

15 Indicators vs. Specific Pathogens Under certain conditions it may be desirable to look for specific pathogens in the environment. Examples: Dry powder operations Dairy powders Spices Dried vegetables/vegetable powders Cereal/grain products Troubleshooting Selection of the specific pathogen(s) depends on the history of the product or process. Examples: Salmonella for dairy powders and spices E. coli O157:H7 for ground beef

16 Environmental Monitoring Locations Where should sampling take place? Food contact surfaces Non-food contact surfaces Environment (air, water, personnel) It is often useful to use the zoning concept in order to track environmental data.

17 Environmental Monitoring Zone 1 Zone 2 Zone 3 Zone 4

18 Environmental Monitoring Zoning Concept Zone 1 Direct and in-direct food contact surfaces Conveyors Slicers Pipes directly over open product zones Zone 3 Other surfaces within the ready-to-eat room Floors Drains Walls Other Equipment Zone 2 Surfaces adjacent to Zone 1 areas Equipment Guards Equipment Framework Zone 4 Remote areas from the RTE manufacturing locations Loading Dock Employee Cafeteria Warehouse

19 Environmental Monitoring Frequency The frequency of environmental monitoring will depend on a number of factors Type of product/process Frequency of cleaning and sanitation (pre-op vs. operational) Maintenance (planned or unplanned) Other factors Generally, weekly is the minimum recommended frequency depending on the situation Daily or multiple times throughout the day may be appropriate for given situations Each plant should establish their own baseline of environmental data

20 Environmental Monitoring Data Examples - Vegetable Processing Operation Pre-Operational and Operational Swabs Time Total Count Data Total Count Per Square Cm. 0 < min 2,400 1 hour 1,100 2 hours 3,000 3 hours 4,700 4 hours 10,000 5 hours 300,000 6 hours 7,300,000 7 hours 75,000,000 8 hours 86,000,000

21 Environmental Monitoring Data Examples - Process Cheese Wet Mix Location Timing Aerobic Plate Count Coliform Count Whey Tank Su <10 <10 Mw 4.8x10 3 <10 Ew 3.1x x10 2 WPC Tank Hold Tank Su <10 <10 Mw 1.5x x10 3 Ew 2.2x x10 4 Su <10 <10 Mw 1.1x x10 3 Ew 8.5x x10 6

22 Project Forward - Listeria Control Program PROJECT FORWARD 3-Stage Approach to Address Preventative & Corrective Actions Sanitation / Environmental Practices Intensive Environmental swabbing Footwear / clothing Traffic patterns Sanitation Maintenance Facility / Equipment Design Facility layout Floors Design for Sanitation Personnel Training GMPs Maintenance Sanitation Behavior based food safety

23 Listeria Equation PROJECT FORWARD Traffic Patterns GMPs Dry, Uncracked, Clean Floors Sanitary Design Sanitation Procedures = Listeria Control Mismanagement of any of the components may increase the risk of cross contamination.

24 Logic Behind Environmental Control Program PROJECT FORWARD Listeria Control Equation is based on premise that environmental monitoring is effective in understanding the plant environment to control Listeria Systematic, disciplined approach to seek out, find and eliminate the undesirable conditions which could support harborage or transference of indicator organisms Focus improvement efforts (capital and resources) as directed by results follow the data

25 Environmental Monitoring Approach PROJECT FORWARD Timely assessment of control of RTE environment Biased intensive sampling during production to validate all components Large surface areas sampled for Listeria genus Sampling is randomized (by the day of the week and shift) Every RTE processing line must be sampled weekly Sampling plans need to be flexible and tailored to each specific line and facility

26 Environmental Monitoring Listeria Control as an Example Environmental monitoring requires a reasonably high level of testing. Positive Listeria spp.. findings will decline with continued emphasis and focus on specific areas. Advise begin testing areas remote to the RTE areas as well as floors of RTE areas before testing adjacent to production or on product contact surfaces This helps to establish a better understanding of Listeria sources in the plant

27 Logic Behind Environmental Control Program PROJECT FORWARD To verify effectiveness of the program, we monitor all components in the Listeria equation Of ~100 RTE meat production lines 50% no positive contact surfaces 84% single occurrence These results indicate the level of Listeria is very low in our environment Low levels in the environment are not likely to result in product contamination

28 Low Levels in the Environment Enumeration Data PROJECT FORWARD Counts of >10 per area swabbed only seen on floor after 2 shifts, or in niches Environmental samples of product contact surfaces tested for Listeria have been enumerated. Positive samples that were enumerated contained less than the detection limit of the methods (MOX and MPN) Data supports concept that random positive product contact surfaces contain few Listeria (<10) that can be transferred to product

29 Corrective Actions PROJECT FORWARD In the event of a positive Listeria species environmental sample, Kraft requires follow- up/ corrective actions. Typical corrective actions include: Review of cleaning records Review of environmental data of the area as well as adjacent areas

30 Corrective Actions (cont d) PROJECT FORWARD Review of line records, for mechanical downtime Audit and interview employees concerning practices during sanitation, set-up, and production Inspections of the area and equipment for potential harborage points Complete a targeted clean

31 Benefits of Aggressive Environmental Monitoring / Corrective Actions PROJECT FORWARD Percent Positive 1.8% 1.48% 1.6% 1.4% 1.2% 1.0% 0.8% 0.6% 0.4% 0.2% 0.0% 1.05% 0.54% Zone 1 Positive Percent Listeria spp. Positive Annual 0.23% 0.16% Year Graph 1 values calculated with the formula (total zone 1 composite + total follow up positive) / (total zone 1 composite samples * 5) + (total follow up samples) Results Reduced Zone 1 + s + 85% since 99

32 Project Forward Validation Program PROJECT FORWARD To measure monitoring program effectiveness, a validation program is in place to assure that the samples taken represent the actual conditions of the entire environment at a given time. Includes multiple sampling points during: Pre-op Operation 2nd shift operation One day for two consecutive weeks Completed once every six months

33 Environmental Monitoring Listeria Control as an Example Environmental monitoring of the entire manufacturing area and adjacent areas is the best possible mechanism to keep the level of risk as low as possible. Only environmental testing allows for systematic, targeted and actionable information to significantly reduce the risk of cross contamination. Essential to any microbiological control program is a documented root cause analysis and preventative/corrective

34 Environmental Monitoring Root Cause Analysis The primary purpose of environmental monitoring is to Provide of a measure of microbiological control effectiveness (trend analysis). Provide investigational data for root cause analysis. Programs will vary by company policy, but they must define what action will be taken and be flexible enough to adapt to changes in the operation and process or to changing regulatory requirements. There are numbers of follow-up actions that should be taken as part of root cause investigational testing.

35 Environmental Monitoring Root Cause Analysis If target organisms (e.g. Listeria spp.) are detected, prompt corrective action steps must be taken and documented Increased frequency of swabbing (e.g. daily from weekly). Increased number of sites (single site samples vs. composite site samples). Conduct by-pass testing isolate potential sources of contamination

36 Corrective and Preventative Actions Traffic Patterns Plan traffic flow to segregate raw and ready to eat materials Establish and maintain separate areas for maintenance and charging of electric carts Control carts, people and equipment that move bulk products (forklifts, carts, hand trucks) Install footbaths and door foamers in plants that have wet environments Require that contractors/visitors to RTE areas follow the same procedures as the work force Install redundant hand washing and sanitation facilities at entry y to each RTE room; post proper washing and sanitation procedures at the entry point

37 Corrective and Preventative Actions GMPs Train and retrain all personnel in GMPs specifically for cross-contamination contamination especially for maintenance and sanitation employees Assign tools and carts to RTE areas to avoid cross- contamination Eliminate brooms from wet RTE areas and replace with rubber-nubbed tools for moving product on the floor

38 Corrective and Preventative Actions Dry, Uncracked,, Clean Floors Keep the plant environment as dry as possible Keep floors clean and crack free Eliminate all leaks in equipment Pipe all water sources (condensates, cooling waters) to a drain

39 Corrective and Preventative Actions Sanitary Design and Sanitation Procedures Determine the efficacy of current periodic cleaning of floors, walls, w and ceilings Clean and maintain HVAC units Clean drains in RTE areas on the same schedule as the room itself Work with suppliers to develop more cleanable processing equipment and transportation equipment such as forklifts Color-code all cleaning supplies to differentiate equipment- cleaning supplies from floor and drain cleaning supplies Minimize use of high pressure hoses Designate storage areas for clean housekeeping equipment

40 Environmental Monitoring Choice of Test Method The choice of test method to be used for environmental monitoring will vary by the type of monitoring being conducted. However, the data being generated is only as good as the method and technique used. Great care must be used to validate the methods to be used for environmental monitoring. Also, the testing laboratory performing the analysis should be validated and certified.

41 Environmental Monitoring Choice of Test Method Listeria spp.. Environmental Sponge Samples BAX PCR Method + ve ve USDA Cultural Method + ve ve In this comparison the BAX PCR screening method for Listeria spp.. Was significantly more sensitive over the USDA cultured method while offering significant time to result savings.

42 Logic Behind Environmental Control Program PROJECT FORWARD Finished product testing has significant limitations. Probability of Missing Contamination Number of Samples Tested % Contamination in Lot 10% 2% 1% 0.5% 3 73% 94% 97% 99% 10 35% 82% 90% 95% 60 <0.5% 30% 55% 74% 120 <0.5% 8.5% 30% 55% 180 <0.5% 2.6% 16% 41% 240 <0.5% 0.8% 9% 30%

43 Environmental Monitoring A Word About Error Rates Testing error rates are an important consideration when conducting analysis. It is imperative to use the best methods, techniques, and controls available to drive error rates down to lowest level possible. Error rates are not only a measure of the testing laboratory, but of the sampling and handling techniques involved.

44 Split Sample Comparison for Qualitative Microbiology August July 1998 % Error % Error % Error Salmonella Pos. Sample Salmonella Salmonella Total Neg. Samples Benchmark Laboratories Total Population ,142 Source: Silliker,, J., American Society for Microbiology, Food Microbiology Division ion Lecture, 1999, Chicago, IL.

45 Logic Behind Environmental Control Program PROJECT FORWARD Statistics demonstrate that finished product testing has severe limitations Finished product sampling is not preventative and does not help identify root cause of contamination Disciplined approach to monitoring promotes knowledge and awareness of the environmental conditions that could result in product contamination If there is an effective kill step in the process, and if there is no Listeria in the environment, there will be no Listeria in the finished product Public health protection is better served with an aggressive environmental program

46 Verifying the Effectiveness of a Practical Microbiological Control Program Conclusions In-process monitoring is the most effective means to measure the success of a microbiological control program. Monitoring verifies that sanitation, GMP s,, and pre-requisite requisite programs are working as they should be. Environmental monitoring is an essential tool for measuring effectiveness of microbiological control programs and as a root cause investigational tool. It is essential that proper test methods and sampling procedures be validated in order to ensure the lowest error rates possible. Proper follow-up actions must be documented to ensure that the process is back within control.

47 Thank You! Questions?