OVERVIEW OF THE USDA ARS & FSIS FRANKFURTER STORAGE STUDY

Transcription

1 OVERVIEW OF THE USDA ARS & FSIS FRANKFURTER STORAGE STUDY John B. Luchansky, Ph.D. John B. Luchansky, Ph.D. Agricultural Research Service Eastern Regional Research Center Microbial Food Safety Research Unit

2 Examples of Research on L. monocytogenes and Frankfurters Efficacy of potassium lactate as an ingredient in batter Porto et al., J. Food Prot. 65: , 2002 with HQM USDA/ARS Package Rinse Method for pathogen recovery Luchansky et al., J. Food Prot. 65: , 2002 Effect of re-heating on viability Porto et al., J. Food Prot. 67:71-76, 2004 Use of PFGE to determine the persistence of a 5-strain cocktail Porto et al., J. Food Prot. 69: , 2003 USDA frankfurter storage study Wallace et al., J. Food Prot. 66: , 2003 with FSIS, AMI, NFPA, NTF Localization within naturally-contaminated packages Wallace, Call, Luchansky et al., J. Food Prot., Published Evaluation of frankfurter casings containing a biopreservative Call/Luchansky et al., J. Food Prot., Published 2004 with Hatfield, Viskase & Rhodia

3 USDA Frankfurter Storage Study Sample packages for Listeria monocytogenes during refrigerated storage: Part A = Determine package prevalence Part B = Estimate pathogen levels Part C = Establish pathogen types Wallace et al., 2003 J. Food Prot. 66:

4 USDA Frankfurter Storage Study Part A: Package Prevalence!

5 Distribution of Volunteer Plants 300 processors contacted 12 facilities volunteered to participate: 9 large and 3 small plants as determined by HACCP classification USDA/FSIS regions 1, 2, 3, and 4 8 USDA/FSIS districts in 10 states ~2700 pounds/packages collected from each facility by a 3 rd -party contractor

6 Sample Size Considerations for an Estimated L. monocytogenes Prevalence of ~3% Confidence Error in P = 25% Error in P = 10% 80% 770 samples 4,809 samples 90% 1,269 samples 7,930 samples 95% 1,802 samples 11,258 samples 99% 3,112 samples 19,445 samples Dr. John G. Phillips, Statistician, USDA/ARS, NAA

7 Terms and Conditions - Industry No identification of plant name or location No inspection activities No regulatory actions or recalls No fingerprint data added to PulseNet

8 Terms and Conditions USDA Independent 3 rd party interacts with plants Collects product, shares results with participants Normal production run, regular HACCP monitoring and GMP No special sanitation prior to production Refrigerated transport to ERRC Temperature recorders placed in select shipping boxes

9 Sampling Plan Day 1 = 5 days post-production 500 packages/pounds sampled Remainder of packages stored at 4 and 10 C Storage at 4 C 200 packages tested on days 10, 20, 30, 45, and 60 Product tested on days 120 and 150 for some plants Storage at 10 C 200 packages tested on days 5, 10, 15, 20, 25, and 30 Product not tested on days 20 and 25 for some plants

10 Sampling Strategy: USDA-ARS Package Rinse Method Add 60 ml peptone water per package and rinse package contents Analyze 25 ml - enrich, isolate, & confirm Retain multiple isolates from each positive sample for subtyping Retain 35 ml at -20 C enumerate if possible 3-tube MPN procedure (FDA/CFSAN)

11 USDA/ARS Package Rinse Method Six-fold more effective at recovery of L. monocytogenes than the approved USDA/FSIS product composite enrichment method because the package, the purge, and the product are tested About twice as likely to recover the bacterium from: rinse > purge > product composite Less likely to cause product contamination and more likely to decrease the time required to sample the product because it requires less hands-on manipulation of the product Luchansky et al., 2002 J. Food Prot. 65:

12 Proximate Composition Six packages tested from each plant 2 packages on initial sample day Day 1 = 5 days after production 2 packages after 30 days at 10 C 2 packages after 60 days at 4 C Portions of each package tested for nitrite, total phenolics, NaCl, ph, protein, moisture, ash, fat, carbohydrates, and lactic acid.

13 USDA Frankfurter Storage Study Facility Size Formulation Season Pounds Assayed Plant 42 Large Pork and Beef Spring 2900 Plant 94 Plant 105 Plant 133 Plant 172 Plant 236 Plant 344 Plant 367 Plant 385 Plant 399 Plant 439 Plant 443 Total Packs Tested Large Turkey** Spring 2700 Large Large Beef Turkey Fall Spring Large Beef Winter 2700 Small Pork and Beef Winter 2900 Large Pork, Beef, and Chicken Fall 2500 Small Pork Summer 2900 Small Large Pork and Beef Pork and Beef Fall Summer Large Pork and Beef* Spring 2300 Large Pork and Turkey Winter 2900 August 2000 through July Contains sodium diacetate** and/or potassium lactate* as an ingredient

14 USDA Frankfurter Storage Study Facility Formulation Packages Assayed/Positive Plant 42 Pork and Beef 2900 Plant 94 Plant 105 Plant 133 Plant 172 Plant 236 Plant 344 Plant 367 Plant 385 Plant 399 Plant 439 Plant 443 Turkey** 2 of 2700 = 0.07% Beef 2800 Turkey 437 of 2800 = 16% Beef 3 of 2700 = 0.11% Pork and Beef 2900 Pork, Beef, and Chicken 4 of 2500 = 0.16% Pork 44 of 2900 = 1.5% Pork and Beef 2 of 2600 = 0.08% Pork and Beef 2800 Pork and Beef* 51 of 2300 = 2.2% Pork and Turkey 2900 Package prevalence = 1.6% (543 of 32,800) Range = 0.07 to 16%

15 Evidence against laboratory contamination Non-disposable equipment, supplies, and laboratory surfaces decontaminated frequently Separation of experiments/incubators to recover the organism from experiments/incubators to type it Pattern and frequency of positive packages does not support carryover or cross contamination Negative controls in place Environmental swabs all 30 negative Glove samples - all 147 negative

16 USDA Frankfurter Storage Study Did storage temperature affect recovery rate? Package prevalence all 12 plants 4 C 314 of 19,100 (1.64%) 10 C 218 of 13,700 (1.59%)

17 USDA Frankfurter Study Did seasonality affect recovery rate? Timeframe August 17 of 2000 through July 3 of 2002 Seasonal Distribution Fall 3 of 12 plants 2 positive plants Winter 3 of 12 plants 1 positive plant Spring 4 of 12 plants 3 positive plants Summer 2 of 12 plants 1 positive plant

18 Recovery rate of L. monocytogenes from all packages during storage at 4 C Day Packages / P e rce nt P ositive /150 Sampling Day

19 Recovery rate of L. monocytogenes from all packages during storage at10 C 5 Day Packages Percent Positive Sampling Day

20 Lactic Acid Bacteria Levels Limited number of packages from each manufacturer evaluated 10 1 to 10 3 cfu/package on day to cfu/package on day 30 following storage at 10EC 10 5 to 10 7 cfu/package on day 60 following storage at 4EC

21 Prevalence of Listeria monocytogenes in Ready-to-eat Foods 1.6% (32,800) Franks USDA/ARS ( ) 1.8% (2,162) Sm. Diam. Sausage USDA/FSIS (1999) 2.8% (31,009) All meat & poultry USDA/FSIS ( ) 3.6% (6,820) Sm. Dia. Sausage USDA/FSIS ( ) 7.6% (1,874) Franks composite Lm Risk Assessment 1.8%(31,700) RTE foods NFPA ( ) Levine et al., JFP 64: , Wallace et al., JFP 66: , Gombas et al., JFP 66: April, 2003.

22 USDA Frankfurter Storage Study Part B: Pathogen Levels!

23 USDA-ARS Package Rinse Method: Sampling Strategy Rinse package contents with 60 ml of peptone water to recover L. monocytogenes Analyze 25 ml determine presence and types Retain 35 ml at -20 C enumerate if possible

24 Sampling Strategy: USDA-ARS Package Rinse Method Retain 35 ml at -20 C enumerate if possible Perform 3-tube MPN test (FDA/CFSAN) Tested 157 rinsates representing all plants Rinsates held at -20 o C for 1 to 23 months Plate directly onto MOX agar Tested 100 rinsates from plant 133 after 150 days at 4 o C Rinsates held at -20 o C for 7 days

25 Enumeration using a 3-tube MPN Of the 157 package rinsates analyzed: Most tested negative after storage at -20 o C 50 to 80% reduction within hours/days 4.0 log 10 reduction after weeks/months 3 packages yielded 71, 95, and 191 MPN/package Plant 367 packages held for 30 days at 10 o C, contents rinsed, and rinsates stored at -20 o C for 2 months prior to MPN

26 Enumeration for L. monocytogenes by direct plating 100 packages from plant 133 were tested following storage at 4 C for 150 days 16 of 100 packages tested positive Rinsates were stored at -20 o C for 7 days and then plated onto MOX agar Levels from < 10 up to 9.6 x 10 4 CFU/package

27 Enumeration of L. monocytogenes from Plant 133 Following Storage at 4 C for 150 Days Number of Packages <10 1.E+01 1.E+02 1.E+03 1.E+04 1.E+05 CFU Per Package Rinsates were stored at -20 o C for 7 days

28 USDA Frankfurter Storage Study Part C: Pathogen Types!

29 USDA Frankfurter Storage Study: Pathogen Types How many different types of L. monocytogenes were recovered? Among 1102 isolates typed: >90% displayed ribotype A" all of these isolates were serotype 1/2a

30 Molecular Subtyping Results In most instances, multiple isolates from a single package and/or from a single producer displayed the same ribotype/serotype. In some instances, it was possible to recover isolates displaying more than one ribotype/serotype from a given producer. In rare instances, multiple isolates from a single package displayed a different ribotype/serotype.

31 USDA Frankfurter Storage Study Part D: Concluding Remarks!

32 Risk Management Question Intended to Answer What is the true prevalence of L. monocytogenes in a high-volume, higher risk, RTE meat? Package prevalence = 1.6% (543 of 32,800) Range = 0.07 to 16%

33 Risk Management Question Intended to Answer How many L. monocytogenes are likely to be recovered from naturally-contaminated RTE meat? Levels ranged from 1 to 100,000 cfu/package

34 Risk Management Question Intended to Answer What types of L. monocytogenes are likely to be recovered from naturally-contaminated RTE meat? Some strains predominate/persist within vacuum-sealed packages - most isolates were ribotype A and serotype 1/2a!

35 Caveats! Manufacturers were not selected at random and only a single lot from each was tested Manufacturers were not reflective of all producers in USA A more effective method (ARS package rinse) was used to sample product/packages Numerous packages were sampled on several sampling days over extended storage of the product. Information was not available about the order in which the packages were produced during a given production run Enumeration was problematic because pathogen numbers decreased appreciably in rinsates during frozen storage

36 THANK YOU! Partners: National Food Processors Association American Meat Institute National Turkey Federation USDA/FSIS ERRC Special Projects Team Morgan Wallace and Jeff Call Anna Porto and Laura Wonderling Gaylen Uhlich and Darrell Bayles