Transcript Compost: A Human Biosecurity Measure

COMPOST: A HUMAN
BIOSECURITY MEASURE
§Some slides adapted from
Johnson County Soil and Water
Conservation District, IN
David Crohn
University of California, Riverside
Central Coast Agriculture
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“America’s salad bowl”
Central Coast Agriculture
Documented outbreaks, 1990 - 2004
CSPI 2006
Spinach Outbreak
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Kyle Algood, age 2 
NY Times
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2006: E. coli O157:H7 victims, 26 states affected
At least 200 cases reported by December 23, 2006
31 suffered kidney failure: hemolytic uremic
syndrome
Three confirmed deaths, another suspected
Spinach has also been distributed to Canada
and Mexico; one case has been reported in
Canada
Compost? Wildlife? Water?
Cal Dept Health Services
and FDA (March 2007):
Compost ruled out
Pathogenic E. coli
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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
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Other pathogenic E. coli
 “traveler’s diarrhea”
 transmitted by contaminated
food, water
 may be minor to severe
Why the sudden concern?
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E.coli 0157:H7 relatively new
Traceback means culprits can be
found and held liable
Water quality structures
Retention ponds
Filter strips
Riparian vegetation
Grassed waterway
Cover crops
Coordinated management of
food safety and water quality
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 20052006 period
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Salmonella
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Arrows indicate Salmonella cells
invading pig epithelium
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
Shigella
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Macrophage infected with
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)
Giardia
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protozoan parasite
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causes diarrhea,
abdominal cramps, nausea
for 4-6 weeks

1-2 week incubation period
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transmitted by
contaminated food/water
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can be transmitted from
animals to humans
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antibiotics are available
Ascaris
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Human roundworm
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8-12 week incubation
period
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causes digestive and
nutritional problems,
abdominal pain
Panic
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Lawyers work to minimize
liability
Auditors hired to inspect fields
 Reject
crops if conditions not met
Central Coast Agriculture
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“America’s salad bowl”
Agriculture can pollute water
Runoff carries sediments which in turn harbor
Nutrients
 Pesticides
 Pathogens
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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
Types of erosion
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Sheet
Rill
Gulley
Photos: NRCS, Wikipedia
Precautionary Principal
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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
Precautionary Principal
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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.”
Measures
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Removal of habitat
Vegetation
 Standing water
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Fences fields to exclude wildlife
Poison
Depends on:
 type of
microorganism
Parasites>viruses>
bacteria
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temperature
Rate of Inactivation
Survival in the Environment
0
10
20
Temperature (C)
30
Survival of Microorganisms in the
Environment
Organism
Total coliform bacteria
Fecal coliform bacteria
Salmonella
Shigella
Enteroviruses
Rotaviruses
Giardia
Cryptosporidium
Ascaris
Time
days - weeks
days - weeks
days - weeks
days
months
months
months - year
months - year
years
Title 14 - Temperature
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Turned windrow – 5 turns over 14 days at 55ºC
 Monitored
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Static pile – 3 days at 55ºC with 6 – 12” insulation
 Monitored
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at 12 – 24”
at 12 – 18”
Daily readings for every 120’ or 200 cu yds
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.
Critical Control Point (CCP)
Identification
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CCPs are
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opportunities to eliminate a
significant hazard
Must be both
 essential
 effective
and
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.
Hazard Assessment
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Relies on flow
diagrams
Comprehensive
Evaluate
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likelihood and
severity of
all
potential threats
proposes mitigation
strategies for
significant threats.
Poultry slaughter
example
Northcutt and Russell (2003)
Critical Control Point (CCP)
Identification
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CCPs are
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opportunities to eliminate a
significant hazard
Must be both
 essential
and
 effective
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These criteria exclude agricultural fields that are both
expansive and exposed.
Northcutt and Russell (2003)
Hazard Analysis and Critical Control Points
(HACCP)
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Critical control points (CCPs) are identified as
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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.
HACCP Prerequisite Programs
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Not established with the same rigor as CCP
Mitigate, but do not fully control, hazards
Good Management Practices (GMPs)
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In the packinghouse
Good Agricultural Practices (GAPs)
In the field
 Water, soil amendment, harvest management
 Personnel hygiene
 Wildlife
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Exclude wildlife
 Eliminate wildlife
 Eliminate habitat
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GAP Metrics – Industry standard
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“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.”
Title 14 - Sampling
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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)
GAP Metrics – Industry standard
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Follow CalRecycle requirements for compost
process
Requires E. coli O157:H7 analysis
Compost Safety
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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