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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 District, IN Slide 2 Central Coast Agriculture Americas salad bowl Slide 3 Central Coast Agriculture Slide 4 Documented outbreaks, 1990 - 2004 CSPI 2006 Slide 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 Slide 6 Compost? Wildlife? Water? Cal Dept Health Services and FDA (March 2007): Compost ruled out Slide 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 travelers diarrhea transmitted by contaminated food, water may be minor to severe Slide 8 Why the sudden concern? E.coli 0157:H7 relatively new Traceback means culprits can be found and held liable Slide 9 Filter strips Riparian vegetation Grassed waterway Cover crops Retention ponds Water quality structures Slide 10 Coordinated management of food safety and water quality Slide 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 2005- 2006 period Slide 12 Salmonella causes diarrhea, fever, cramps 12-72 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 Slide 13 Shigella bacteria causes diarrhea (often bloody), fever, cramps 24-48 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 Slide 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 Slide 15 Ascaris Human roundworm 8-12 week incubation period causes digestive and nutritional problems, abdominal pain Slide 16 Panic Lawyers work to minimize liability Auditors hired to inspect fields Reject crops if conditions not met Slide 17 Central Coast Agriculture Americas 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 Slide 18 Types of erosion Sheet Rill Gulley Photos: NRCS, Wikipedia Slide 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 Slide 20 Precautionary Principal Buyers 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? Thats good. One less thing. Slide 21 Measures Removal of habitat Vegetation Standing water Fences fields to exclude wildlife Poison Slide 22 Concentrations of Pathogens in Stools of Infected Individuals from Gerba, 1995 Slide 23 Survival in the Environment Depends on: type of microorganism Parasites>viruses> bacteria temperature Slide 24 Survival of Microorganisms in the Environment Slide 25 Title 14 - Temperature Turned windrow 5 turns over 14 days at 55C Monitored at 12 24 Static pile 3 days at 55C with 6 12 insulation Monitored at 12 18 Daily readings for every 120 or 200 cu yds Slide 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. Slide 27 Critical Control Point (CCP) Identification CCPs are opportunities to eliminate a significant hazard Must be both essential and effective Slide 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. Slide 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 Slide 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) Slide 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. Slide 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 Slide 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. Slide 34 Title 14 - Sampling Compost sampling 1 composite sample for each 5000 cu yd Composite of 12 samples from different depths Fecal coliforms ( Slide 35 GAP Metrics Industry standard Follow CalRecycle requirements for compost process Requires E. coli O157:H7 analysis Slide 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