Pre harvest Interventions to Reduce Carriage of E. coli O157.

Transcription

1 Pre harvest Interventions to Reduce Carriage of E. coli O157. Guy H. Loneragan Epidemiologist Feedlot Research Group West Texas A&M University Mindy M. Brashears International Center for Food Industry Excellence Texas Tech University 51 st International Congress of Meat Science and Technology Baltimore, Maryland, August 9 th, 2005

2 Outline of presentation The need for pre harvest intervention Carriage and carcass contamination Issues with pre harvest control Relationship between fecal and hide carriage Where to focus effort Pre requisites requisites Pre harvest interventions Results of various products Focus on in field testing

3 E. coli O157 and human exposure While not the only source of E. coli O157, cattle appear to be the primary reservoir. Human exposure: Beef via contamination of carcasses at harvest Non beef sources Cattle origin of bacteria?

4 Human illnesses Human Incidence, per 100, CDC cases / 100,000 people 2010 National Target Presumably due to decrease in exposure of population

5 E. coli O157 Even though illnesses have declined, prevalence among cattle remains high. Seasonal peak No evidence prevalence changed Yet USDA:FSIS positives have decreased. 1.2 % positive ground beef

6 E. coli O157 Due largely to efforts of packing plants Appropriate that effort has been placed within this segment of the industry Structure of the US beef industry Point of constriction at packing plants Cow/Calf Seed Stock Stocker Feedlot Packer Processor Retailer Consumer Foodservice 800,000 2,700 85% 35 95% 280,000,000

7 Importance of pre harvest carriage Recent body of literature has associated pre harvest carriage with likelihood of carcass contamination with E. coli O157. Elder et al. PNAS 2000 Pre harvest prevalence (feces or hide) associated with post harvest contamination.

8 Importance of pre harvest carriage Arthur et al. JFP 2004 Pre harvest prevalence associated with post harvest contamination. reducing the number of bacteria and pathogens on the hide can have a large impact on the levels of pathogens on the carcass.

9 Importance of pre harvest carriage Ransom et al., ISVEE 2003 Visited feedlots prior to shipment then followed pens through the packing plant. Dichotomized pre shipment fecal prevalence < 20 or > 20% of fecal samples positive Sampled at various time points along the chain. Samples Hide (in plant), % Colon, % Pre evisceration, evisceration, % Post evisceration, % Hot box, % E. coli O157 fecal Prevalence > 20% < 20%

10 Importance of pre harvest carriage The accumulated data provide compelling evidence that pre harvest carriage of E. coli O157 impacts carcass contamination. Hides likely source of carcass contaminants Feces source for hide contamination Interventions that reduce carriage should reduce the likelihood for carcass contamination. Recently, several potential interventions have been evaluated in the field. More in development

11 Issues with pre harvest control Studies using naturally infected cattle most closely mimic commercial production. Estimates of hide carriage in harvest ready cattle are best data upon which to make sound recommendations. However, not all studies have measured hide carriage Ignore studies with only feces results? Are fecal and hide carriage associated?

12 Issues with pre harvest control Included data from 6 studies performed over the past 2 years. Evaluated pen level hide prevalence as a function of fecal prevalence Logistic regression techniques 2572 samples from 1286 animals 13.1% of feces and 13.9% of hides were positive. Range: 0.0% to 91.7% (feces) / 68.0% hides

13 100 Issues with pre harvest control Hide prevalence, % Lower 95%CL Model Upper 95%CL Fecal prevalence, %

14 Bottom line Reduced pathogen load on hides entering plants results in a product less likely to have E. coli O157. Improves the efficiency of in plant interventions. Fecal prevalence provides predictive information about hide carriage

15 Where to focus pre harvest effort Aim: reduce the pathogen load entering plants Will improve the efficiency of in plant interventions. Cow/Calf Seed Stock Stocker Feedlot Packer Processor Retailer Consumer Foodservice 800,000 2,700 85% 35 95% 280,000,000

16 Where to focus pre harvest effort Aim: reduce the pathogen load entering plants Will improve the efficiency of in plant interventions. Cow/Calf Stocker Feedlot Packer Processor Seed Stock Retailer Consumer Foodservice 800,000 2,700 85% 35 95% 280,000,000

17 Two aspects for successful implementation of pre harvest control Prerequisites for success of program: Clean Feed Clean Water Well drained housing Appropriate pest control Targeted intervention technology: Dependent upon implementation of prerequisites E. coli O157 solutions: The pre harvest commitment; Produced by NCBA

18 Two aspects for successful implementation of pre harvest control Prerequisites for success of program: Clean Feed Clean Water Well drained housing Appropriate pest control Targeted intervention technology: Dependent upon implementation of prerequisites E. coli O157 solutions: The pre harvest commitment; Produced by NCBA

19 Dietary Interventions Biological e.g., DFM (probiotics or CE), other Chemical e.g., chlorate, neomycin, chlorination Immunomodulation Vaccine Physical (beyond focus of presentation) Hide cleaning Preventing re contamination

20 Direct Fed Microbials (DFM) Lactobacillus spp. Good bacteria e.g., e.g., found in yogurt Few strains effective (Brashears et al, (Brashears et al, JPF 2003). 650 candidate strains Narrowed down to one strain (NP51) Marketed as Bovamine Culture Complex Probiotic, NPC Has GRAS status

21 Feedlot studies of NP51 Results based on fecal prevalence 35 Fecal Prevalence % reduction % reduction % reduction % reduction

22 Feedlot studies of NP51 Results based on hide carriage 35 Hide Prevalence % reduction % reduction % reduction 2004 not evaluated

23 Feedlot studies of NP51 4 year average Log cfu Feces 3.2 Control 14.3 Hides 0.9 NP Average reduction: 62.5% feces 72.7% hides Fecal load in positive animals reduced by greater 99.5% 10 15% 15% of Nation s fed cattle consuming this product

24 Feedlot studies of PROBIOS FS Chr.. Hansen % pens cattle % pens positive Control PROBIOS FS 3.3 Fed for last 14 days on feed. Average reduction: 56% feces Hides not evaluated Has GRAS status. Limited use 0 Control PROBIOS FS

25 Immunomodulation 2 pre licensure products evaluated in feedlots Bioniche and Ft. Dodge AH Initial results encouraging Bioniche Potter et al., Vaccine,, 2004 Feces 8.8 Hide Reduction: Feces 58.7% Hides not evaluated Ft. Dodge Feces Hides Keith Belk, CSU Hide 20 Reduction: Feces 70.1% Hides 50.4%

26 Immunomodulation Dave Smith, Rodney Moxley,, Terry Klopfenstein, Galen Erickson, Susanne Hinkley,, Robert Peterson Fecal prevalence, % External controls 1 dose 2 doses 3 doses 2003 study Vaccinated 0, 1, 2, 3 times 67 73% 73% efficacy Herd immunity demonstrated RAJ colonization, % Study 1 Study studies Small and large pens studies Colonization at RAJ junction 76 97% vaccine efficacy

27 Neomycin E. coli O157 prevalence Reduction: Feces 98.2% Hides 95% Theuninck Cargill Feces Hides E. coli O157 prevalence Reduction: Feces 100% Hides 78.9% Belk CSU Feces Hides

28 Neomycin and E. coli O157 control Rapid effect on hides: Residual neomycin Hide carriage is more dynamic than previously thought No doubt it is the most effect product tested to date Used in feed or water for 2 to 3 days and 1 day1 withdrawal. No label claim for E. coli O157 control: Extra label in feed/in feed/in water use prohibited Issues with antibiotic use in food animals Perception and unknown consequences

29 Waterer Chlorination study Conducted in a large commercial feedlot Prevalence Control Chlorinated P = 0.70 P = 0.45 P = Feces Hides Side Hide Midline Source of data: Dr. Duane Theuninck Cargill

30 Feedlot TASCO 14 study Conducted in a large commercial feedlot Prevalence Control TASCO14 P = 0.94 P = 0.46 P = Feces Hides Either 61.0 Source of data: Dr. Duane Theuninck Cargill

31 Other DFM Others Competitive exclusion using non pathogenic E. coli Sodium chlorate Suicide substrate for facultatively anaerobic bacteria such as E. coli and Salmonella Waiting for regulatory approval In field testing soon (we hope). Others e.g., bacteriophage.

32 The need for pre harvest interventions Most efforts to control E. coli O157 have been in the packing plant Natural point of control Pre harvest carriage can still overwhelm system Carriage reduction will improve the efficiency of in plant interventions.

33 Issues with pre harvest control Initial focus will be on confined cattle operations. 2,700 operations account for >85% of fed cattle Prerequisites for control Clean feed, clean water, housing, pests

34 Pre harvest interventions Several interventions show promise in feedlot settings No intervention will be 100% Available products Bovamine from NPC; PROBIOS FS from Chr. Hansen Products in the approval pipeline or approval needed Vaccine, sodium chlorate, CE, neomycin Pre harvest control of E. coli O157 is in effect today and will become a more common practice in the future.

35 Data sources Duane Theuninck Keith Belk Justin Ransom Dave Smith et al. Collaborators Mindy Brashears Mike Galyean, Mike Brown Paul Defoor Doug Ware Acknowledgements WTAMU students Lindsay Chichester Tammy Platt Lacey Proffit DJ Kunze TTU students Spring Younts Dahl Will Winter Tyler Stevens Jason Mann

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