Presentation on theme: "Listeria Monitoring & Testing in RTE seafood plants"— Presentation transcript:
1 Listeria Monitoring & Testing in RTE seafood plants What to test, how to test, & how to take appropriate action
2 Goal of Listeria testing and monitoring testing program is to FIND Listeria Listeria testing provides an opportunity to identify problems before they lead to finished product contamination, recalls, & regulatory actions
3 What to test? Raw materials Finished Products Processing plant environment (all areas including raw, in-process, and finished product areas)Food contact surfacesNon-food contact surfaces
4 What to test for? Listeria monocytogenes Listeria species The specific type (species) of Listeria that can cause human diseaseListeria speciesIncludes different species of Listeria, such as Listeria monocytogenes as well as Listeria innocua and others, which do not cause human disease
5 Why test for Listeria monocytogenes? It is the specific type that causes human diseaseListeria monocytogenes specific testing is generally conducted when finished products are tested since only L. monocytogenes is considered an adulterantListeria testing may not always be a good indicator for presence of L. monocytogenesSometimes only 5-10% of Listeria species positive samples harbor L. monocytogenesIf finished product would be tested for Listeria spp. and would be found positive follow-up testing for L. monocytogenes would be required
6 Why test for Listeria species More common than Listeria monocytogenes, thus more appropriate for routine monitoringTest results may be available more rapidly than for Listeria monocytogenesTesting may be cheaper than Listeria monocytogenes testingListeria species testing generally used for environmental samples
7 Raw material testingMay be important for raw materials to be used for cold smoking, which is a process that does not kill ListeriaMay be used to test raw materials from new suppliersMay be used to continuously monitor raw materials from suppliers
8 Finished product testing Finished product testing is NOT an essential part of a L. monocytogenes control programSometimes conducted at request of customersFinished product testing requires specific definition of lots:L. monocytogenes positive lots in commerce have to be recalledIn a test and hold program (which is recommended), L. monocytogenes positive lots have to be reprocessed or destroyed
9 Environmental Listeria testing An essential part of each Listeria control program
10 Why environmental Listeria testing and monitoring? Finished product contamination can most commonly be traced back to Listeria found in the processing environmentFinding of environmental samples positive for Listeria does not require product recallRegulatory agencies are developing directives and guidance encouraging regular environmental Listeria testing
11 Goals of an environmental Listeria testing program Identify problem areas harboring Listeria and locate contamination sourcesConfirm effectiveness of problem-solving procedures
12 Critical considerations for environ-mental Listeria monitoring program Design of environmental testing programWhen to test (before start-up; mid-shift; end of shift?)Where to test (product contact surfaces, cart wheels, drains?)How often to test (weekly, monthly?)Response to a positive sample
13 Environmental Listeria monitoring plan Each environmental monitoring plan should be specific to the individual processing facility.Listeria spp. testing is recommended for non-product and product contact surfaces
14 Where to test? Food contact surfaces Non-food contact surfaces Food contact surface positives may have to be followed up with finished product testingNon-food contact surfacesSites in coolers (floors, walls, cooler coils, condensate collectors etc.)Tubs, conveyances, underneath tablesFloors, floor mats, walls, & drains in production areas
15 Testing of non-food contact surfaces Initial weekly sampling is recommended for most wet areas where Listeria can growSome sampling sites should be constant (i.e., same site should be sampled regularly), but others can varyAdditional samples may need to be taken in proximity of positive samples
16 Where to test – the zone concept Plant is divided into different zones; zones are defined based on relative potential for finished product contamination a site or area represents; sampling and corrections triggered by positive samples differ by zones.Zone 1: Finished product contact surfacesZone 2: Non-food contact surfaces in finished product areaZone 3: Product contact surfaces in raw product handling areasZone 4: Areas remote from finished product handling (e.g., non-product contact surfaces in the raw product handling areas)
17 When to test? Pre-op Mid-op Less likely to yield positive samples More easy to interpret, will identify sanitation weaknessesMid-opMore likely to yield positiveWill provide information on spread of Listeria during processing
18 What to do with testing results Review testing results every time results are reportedThis should include review of last 4-8 sampling results to identify trends (e.g., site that has positives with intervening negativesTake corrections on each positive sample and document action
19 What to do with testing results (cont’d) Organize testing results in one location (folder, three-ring binder)Include documentation of corrections in same locationConduct regular (quarterly, yearly; depends on testing frequency & volume) review of testing resultsTabulate and evaluate long-term trends
20 Guidelines for corrective actions Corrections based on positive samples need to be plant specificEach positive sample should be followed up with additional investigationsTrend towards increased frequency of Listeria spp. needs to be investigated to determine reason and action needs to be taken to reduce frequency
21 Guidelines for corrective actions (cont’d) Additional samples should be taken from environmental area that showed positive resultsAdditional positive samples after corrections need follow up with intensified cleaning and re-testingProblems areas may have to be shut down temporarilyConsider if a test and hold program is needed
22 How is environmental testing performed? Sponges are used to collect samples from selected environmental sitesKits for sterile sample collection are available from testing laboratoriesHands-on training in proper sampling technique should be performed by professionalEnvironmental samples should represent constant areas (e.g., 2 x 2 ft)Product contact surface samples should be collected from areas as large as possible
23 How is environmental testing performed? (cont’d) After sample collection, sponge is deposited in sterile plastic bag and sealedSponges are sent to laboratory for testing
25 Pic 3#; mention that sample should be taken mid-op, and not pre-op on clean surface
26 Example – Medium sized plant pro-ducing hot & cold smoked products Plant only tests environmental samples (non-product contact surfaces and product contact surfaces)All testing is for Listeria spp.
27 Testing planSamples from 10 non-food contact surfaces are tested weekly; samples taken before production starts6 sites in finished product area (1 floor sample near slicer; 1 sample from underneath tables used for product packaging, 2 employee contact surfaces, 1 floor drain, 1 sample from cart wheels4 sites in raw material handling area (1 raw material cooler floor, 1 brining cooler floor, 1 floor drain, 1 underneath table used for raw material prep)
28 Testing plan (cont’d)Samples from 5 product contact surfaces are tested weekly; samples taken at least 3 h after production started1 sample from blade of slicing machine1 sample from scale used to weigh product before packaging1 sample from skinning machine conveyer belt1 sample from trimming knife1 sample from totes used to move cold-smoked products
29 Corrections – non-product contact surfaces Raw material sites with positive results for 2 consecutive weeks will receive more stringent cleaning and sanitizer rotation until at least 3 of 4 consecutive tests are negativeFinished product area sites with a positive result will receive immediate attention and re-testing.If re-test is positive line may be shut down (or go to test and hold procedure for finished products) and additional cleaning and sanitizing, including line disassembly will be implemented until three consecutive daily samples are negative.
30 Corrections – product contact surfaces Sites with a positive result will receive immediate intensified cleaning and sanitizing, as well as daily sampling. If 2 consecutive samples are positive the area is shut down and extensive sanitation procedures are implemented. Swabs are taken before start-up and at two-hour intervals until 3 consecutive negative samples demonstrate that the contamination source has been eliminated; at that point routine testing can be resumed.
31 SummaryListeria testing plan may include raw and finished product testingEnvironmental Listeria testing is necessary to control this pathogenTesting plant needs to be developed individually for each operationPositive testing results need to be followed up with corrections, which need to be documented
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