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COMPOST: A HUMAN BIOSECURITY MEASURE David Crohn University of California, Riverside §Some slides adapted from Johnson County Soil and Water Conservation.

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Presentation on theme: "COMPOST: A HUMAN BIOSECURITY MEASURE David Crohn University of California, Riverside §Some slides adapted from Johnson County Soil and Water Conservation."— Presentation transcript:

1 COMPOST: A HUMAN BIOSECURITY MEASURE David Crohn University of California, Riverside §Some slides adapted from Johnson County Soil and Water Conservation District, IN

2 Central Coast Agriculture  “America’s salad bowl”

3 Central Coast Agriculture

4 Documented outbreaks, CSPI 2006

5 Spinach Outbreak Kyle Algood, age 2 NY Times  2006: E. coli O157:H7 victims, 26 states affected  At least 200 cases reported by December 23, 2006  31 suffered kidney failure: hemolytic uremic syndromehemolytic uremic syndrome  Three confirmed deaths, another suspected Spinach has also been distributed to Canada and Mexico; one case has been reported in CanadaMexico

6 Compost? Wildlife? Water? Cal Dept Health Services and FDA (March 2007): Compost ruled out

7 Pathogenic E. coli  E. coli O157:H7  waterborne and foodborne outbreaks documented  bloody diarrhea  may cause acute kidney failure, death  Can survive if reintroduced into compost  Low infectious dose  Other pathogenic E. coli  “traveler’s diarrhea”  transmitted by contaminated food, water  may be minor to severe

8 Why the sudden concern?  E.coli 0157:H7 relatively new  Traceback means culprits can be found and held liable

9 Filter strips Riparian vegetation Grassed waterway Cover crops Retention ponds Water quality structures

10 Coordinated management of food safety and water quality

11 November 3, 2006  FDA announces that fresh tomatoes served in restaurants had sickened 183 people in 23 states with Salmonella typhimurium  One of four such outbreaks during the period

12 Salmonella  causes diarrhea, fever, cramps hours after infection  illness lasts 4-7 days  can also cause typhoid fever  40,000 cases reported annually; 1000 deaths annually  0.1% population excretes Salmonella at a given time  most common bacterial pathogen in wastewater  primarily foodborne (beef, poultry, milk, eggs), but also transmitted by water Arrows indicate Salmonella cells invading pig epithelium

13 Shigella  bacteria  causes diarrhea (often bloody), fever, cramps hours after infection  illness lasts 5 -7 days  infect only humans  18,000 cases reported annually  primarily transmitted by direct contact with infected individual  also transmitted by contaminated food, water, recreation  low infectious dose (~10 organisms) Macrophage infected with Shigella

14 Giardia  protozoan parasite  causes diarrhea, abdominal cramps, nausea for 4-6 weeks  1-2 week incubation period  transmitted by contaminated food/water  can be transmitted from animals to humans  antibiotics are available

15 Ascaris  Human roundworm  8-12 week incubation period  causes digestive and nutritional problems, abdominal pain

16 Panic  Lawyers work to minimize liability  Auditors hired to inspect fields  Reject crops if conditions not met

17 Central Coast Agriculture  “America’s salad bowl”  Agriculture can pollute water  Runoff carries sediments which in turn harbor  Nutrients  Pesticides  Pathogens  Pajaro River, Elkhorn Slough impacted with sediments and nutrients  Salinas River impacted with all four  Growers are not exempt from water discharge laws and are operating under a conditional waiver

18 Types of erosion  Sheet  Rill  Gulley Photos: NRCS, Wikipedia

19 Precautionary Principal  When an activity raises threats of harm to human health or the environment, precautionary measures should be taken even if some cause and effect relationships are not fully established scientifically (Wingspread Statement, 1998).  “Is it possible for X to vector disease or to attract disease vectors?” If yes then:  “Is X necessary to grow crops?” If no, then:  Target for audits

20 Precautionary Principal  Buyer’s attorneys and insurance companies hold influence  “Is it possible for wildlife to vector disease? Can they be eliminated?”  “Is compost absolutely necessary to grow crops?”  “That’s good. One less thing.”

21 Measures  Removal of habitat  Vegetation  Standing water  Fences fields to exclude wildlife  Poison

22 Concentrations of Pathogens in Stools of Infected Individuals from Gerba, 1995

23 Survival in the Environment Depends on:  type of microorganism Parasites>viruses> bacteria  temperature

24 Survival of Microorganisms in the Environment

25 Title 14 - Temperature  Turned windrow – 5 turns over 14 days at 55ºC  Monitored at 12 – 24”  Static pile – 3 days at 55ºC with 6 – 12” insulation  Monitored at 12 – 18”  Daily readings for every 120’ or 200 cu yds

26 The Seven HACCP Principals (1) Assess hazards (2) Identify reliable safety measures (Critical Control Points) (3) Assign acceptable performance parameters (critical limits) (4) Monitor, (5) Maintain, (6) Verify, and (7) Document program performance.

27 Critical Control Point (CCP) Identification  CCPs are  opportunities to eliminate a significant hazard  Must be both  essential and  effective

28 The Seven HACCP Principals (1) assess hazards (2) identify reliable safety measures (critical control points) (3) assign acceptable performance parameters (critical limits) (4) monitor (5) maintain (6) verify, and (7) document program performance.

29 Hazard Assessment  Relies on flow diagrams  Comprehensive  Evaluate  likelihood and severity of all potential threats  proposes mitigation strategies for significant threats. Northcutt and Russell (2003) Poultry slaughter example

30 Critical Control Point (CCP) Identification  CCPs are  opportunities to eliminate a significant hazard  Must be both  essential and  effective  These criteria exclude agri- cultural fields that are both expansive and exposed. Northcutt and Russell (2003)

31 Hazard Analysis and Critical Control Points (HACCP)  Critical control points (CCPs) are identified as  opportunities to eliminate a significant hazard  must be both essential and effective  These criteria exclude agricultural fields that are both expansive and exposed.  Interventions in the field are, therefore, referred to as prerequisite programs.  reducing pathogen or other hazards, but are not established with the same rigor, nor are they relied upon to protect consumer health. Like MPs, they mitigate, but do not fully control, hazards.

32 HACCP Prerequisite Programs  Not established with the same rigor as CCP  Mitigate, but do not fully control, hazards  Good Management Practices (GMPs)  In the packinghouse  Good Agricultural Practices (GAPs)  In the field  Water, soil amendment, harvest management  Personnel hygiene  Wildlife Exclude wildlife Eliminate wildlife Eliminate habitat

33 GAP Metrics – Industry standard  “Do not use crop treatments that contain raw manure for lettuce or leafy green produce.”  “Verify that the time and temperature process…”  “Maximize the time interval between the crop treatment application and time to harvest.”  “Segregate equipment used for crop treatment applications or use effective means of equipment sanitation before subsequent use.”

34 Title 14 - Sampling  Compost sampling  1 composite sample for each 5000 cu yd  Composite of 12 samples from different depths  Fecal coliforms (<1000 MPN/dry g)  Salmonella (<3 MPN/4 g)

35 GAP Metrics – Industry standard  Follow CalRecycle requirements for compost process  Requires E. coli O157:H7 analysis

36 Compost Safety  Long track record  Not controversial, but regularly investigated  Used all over the world without problems  Samples do occasionally reveal pathogens  Best available alternative: A biocontrol measure!  Cross-contamination


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