Survival of PEDV in Feed, Feed Ingredients, and Interventions:
Feed Mitigation Strategies
Dr. Cassie JonesAllen D. Leman Swine Conference
Prevention of Biological Hazards in Feed• Why is PEDV mitigation important?
• Food Safety Modernization Act– Most feed mills will need to establish Animal Food
Safety Plans to identify and control hazards• Agents that have the potential to cause illness or injury or in
humans or animals • Include microbiological pathogens, such as viruses
Swine Health Monitoring Project, 2015
Prevention of Biological Hazards in Feed• Why is PEDV mitigation important?– Our charge in feed manufacturing:
Control animal food safety hazards to fulfill our role in preserving farm-to-fork food safety.
Prevention of Biological Hazards in Feed• Prevention
– Exclusion (biosecurity)• Ingredients• People• Transportation
• Proactive mitigation– Point-in-time
• Thermal• Irradiation (UV, UVC, ionizing)• Dilution
– Residual• Chemicals
– Acids and alkalis– Formaldehyde– Medium chain fatty acids– Essential oils
Depending on your risk and aversion to it, multiple strategies may be combined
Prevention of Biological Hazards in Feed• Prevention– Exclusion (biosecurity)• Ingredients• People• Transportation
– Resources• Feed Mill Biosecurity session tomorrow morning (Room 8)
– Jason Woodworth– Laura Greiner– Tim Snider
• AFIA’s “Developing Biosecurity Practices for Feed & Ingredient Manufacturing”
Prevention of Biological Hazards in Feed• Proactive mitigation– Point-in-time• Thermal• Irradiation (UV, UVC, ionizing)• Dilution
– Residual• Chemicals
– Acids and alkalis– Formaldehyde– Medium chain fatty acids– Essential oils
Cargill Feed Safety Research Center• O.H. Kruse Feed Technology Innovation Center at
Kansas State University– Cargill Feed Safety Research Center
• 3 story BSL-2 Lab– Salmonella, E. Faecium, PEDV– Pellet mills, coolers, and bagging capacities– Containment mode
• Equipped with sanitation features• Air flow alarms• HEPA filters• Decontamination
Point-in-Time Mitigation• Thermal mitigation of PEDV by pelleting– Exp. 1 • Low dose and high dose (20 and 13 Ct) • 3 pellet mill conditioner retention times (45, 90, 180 s)• 3 conditioning temperatures (155, 175, 195°F)
Point-in-Time Mitigation• Thermal mitigation of PEDV by pelleting– Exp. 1
Low Dose PCR Ct Values (20 Ct) Time, secTemp, °F 45 90 180
155 43 40 45175 37 40 42195 40 37 36
Low Dose Feed No processing = 31
High Dose PCR Ct Values (13 Ct) Time, sec Temp, °F 45 90 180
155 30 30 30175 30 30 30195 30 31 30
High Dose Feed No processing = 24
No infectivity developed from any of the pelleted diets
Point-in-Time Mitigation• Thermal mitigation of PEDV by pelleting– Exp. 2• Single dose (11 Ct)• Single conditioner retention time (30 s)• 5 conditioning temperatures (100, 115, 130, 145, and 160°F)• Replicated manufacturing conditions
– 3 pigs/room – one from each manufacturing rep
Point-in-Time Mitigation• Thermal mitigation of PEDV by pelleting– Exp. 2 (3 replications)
PCR Ct Values Time, secTemp, °F 30
100 32.5115 34.7130 37.0145 36.5160 36.7
Point-in-Time Mitigation• Thermal mitigation of PEDV by pelleting– Exp. 2 (3 replications)
Number of Pigs Infected with PEDV by Bioassay
Feed 0 dpi 2 dpi 4 dpi 6 dpi 7 dpi7 dpi
CecumNo PEDV 0 0 0 0 0 0 0100°F 9/9 0 1/9 3/9 3/9 3/9 3/9115°F 9/9 0 3/9 3/9 3/9 3/9 3/9130°F 9/9 0 0 0 0 0 0145°F 8/9 0 0 0 0 0 0160°F 8/9 0 0 0 0 0 0
Infectivity developed in diets pelleted below 130°F
Point-in-Time Mitigation• Thermal mitigation of PEDV by pelleting– When is feed NOT conditioned to at least 130°F?• Intentional extremely low conditioning temperatures (rare)• Start-up• Plugged dies
– Other potential mitigation strategies may be necessary to consider IN ADDITION to pelleting
Point-in-Time Mitigation• Irradiation of PEDV –Dose-dependent• 99.97% virus inactivation at 50 kGy– 44 kGy recognized by NASA for sterilization of frozen
packaged meats• 90% virus inactivation at 10 kGy– 3 and 4.5 kGy recognized by FDA 21 CFR 179.26 for
pathogen control in eggs and refrigerated uncooked meat products, respectively
–Potential for ingredients–Not practical for large-scale feed production
Goyal et al.
Point-in-Time Mitigation• Dilution of PEDV– Sequencing or flushing are recognized cleanout
procedures for CGMPs of medicated feed– One batch of PEDV-negative feed mixed, conveyed
through bucket elevator, discharged– One batch of PEDV-positive feed followed– Four subsequent sequences of PEDV-negative feed
followed• Feed and environmental samples at multiple locations
collected after each batch
Point-in-Time Mitigation• Dilution of PEDV
Number of Pigs Infected with PEDV by Bioassay Time Point
Location
AfterPEDVDiet
After Sequence
1
After Sequence
2
After Sequence
3
After Sequence
42 dpi (fecal) 9/9 1/9 1/9 ? ?
7 dpi (cecum) 9/9 3/9 3/9 ? ?
Number of Feed Samples When PEDV was Detected by PCR Time Point
Location
AfterPEDVDiet
After Sequence
1
After Sequence
2
After Sequence
3
After Sequence
4Mixer 9/9 7/9 0 0 0
Bucket Elevator 9/9 7/9 2/9 0 0
Point-in-Time Mitigation• Dilution of PEDV – Why is infectious RNA still present in the next batch?
Baselin
e
After Neg.
Diet
After PEDV Diet
After Flush
1 Diet
After Flush
2 Diet
After Flush
3 Diet
After Flush
4 Diet
After Syn
ergize
After Bleach
After 48 h Hea
t0.0
20.0
40.0
60.0
80.0
100.0
Positi
ve C
t for
PED
V, %
Problem with Point-in-Time Mitigation• Does not eliminate potential for cross-
contamination–Within mill: Conveyors, coolers, bins, load-out– Transportation: Trucks, unloading–Within farm: Bins, feed lines, feeders
Residual Mitigation• Proactive mitigation– Point-in-time• Thermal• Irradiation (UV, UVC, ionizing)• Dilution
– Residual• Chemicals
– Acids and alkalis (Goyal et al.)– Formaldehyde (Dee et al.)– Medium chain fatty acids– Essential oils
Residual Mitigation• Chemical treatments
1. Untreated control2. Commercial formaldehyde (Termin-8)3. Essential oil mixture (garlic, turmeric, capsicum, oregano, and rosemary,
1:1 blend, 2% wt/wt)4. Medium chain fatty acid mixture (caproic acid, caprylic acid, and capric
acid, 1:1 blend, 2% wt/wt)5. Organic acid mixture (lactic acid, propionic acid, formic acid, benzoic acid,
1:1 blend, 3% wt/wt)6. Sodium bisulfate (1%)7. Sodium chlorate (1%)
• Four feed matrices: swine diet, avian blood meal, porcine meat and bone meal, and spray dried porcine plasma
PEDv contamination post-treatment in swine diets stored at room temperature
0 5 10 15 20 25 30 35 40 452628303234363840
Untreated control Medium chain fatty acid Essential oilOrganic acid Sodium bisulfate Sodium chlorateCommercial formaldehyde
Day
Qua
ntita
tive
CT V
alue
s
Ingredient × day, P < 0.0001Treatment × day, P < 0.0001Ingredient × treatment, P < 0.0001
PEDv contamination post-treatment in avian blood meal stored at room temperature
0 10 20 30 40242628303234363840
Untreated control Medium chain fatty acid Essential oil Organic acidSodium bisulfate Sodium chlorate Commercial formaldehyde
Day
Qua
ntita
tive
CT V
alue
s
Ingredient × day, P < 0.0001Treatment × day, P < 0.0001Ingredient × treatment, P < 0.0001
PEDv contamination post-treatment in porcine meat and bone meal stored at room temperature
0 10 20 30 40242628303234363840
Untreated control Medium chain fatty acid Essential oilOrganic acid Sodium bisulfate Sodium chlorateCommercial formaldehyde
Day
Qua
ntita
tive
CT V
alue
s
Ingredient × day, P < 0.0001Treatment × day, P < 0.0001Ingredient × treatment, P < 0.0001
PEDv contamination post-treatment in spray dried porcine plasma stored at room temperature
0 10 20 30 4026
28
30
32
34
36
38
40
Untreated control Medium chain fatty acid Essential oil Organic acidSodium bisulfate Sodium chlorate Commericial formaldehyde
Day
Qua
ntita
tive
CT V
alue
s
Ingredient × day, P < 0.0001Treatment × day, P < 0.0001Ingredient × treatment, P < 0.0001
Untreated controls stored at room temperature
0 10 20 30 40242628303234363840
Swine diet Blood meal Porcine meat and bone meal Spray dried animal plasma
Day
Qua
ntita
tive
CT V
alue
s
• Time, formaldehyde, medium chain fatty acid, and essential oil treatment all enhance the degradation of PEDV RNA in feed ingredients– Varies within the feed matrix– Not necessarily indicative of infectivity
• Stability of PEDV varies over time depending upon matrix• Ongoing: – Evaluation of appropriate concentrations, combinations, and
effectiveness of MCFA by bioassay– Evaluation of MCFA in various ingredients by VI, bioassay– Evaluation of various dry and wet applications for surface
decontamination
Residual Mitigation
• Diets pelleted with a 30 s conditioning time above 130°F were non-infectious.– Considerations required for plugs, start-up of pellet mills
• Irradiation may be effective, but is only practical for ingredients• Sequencing diets dilutes PEDV, but infectivity remains
– Particularly on equipment surfaces• Formaldehyde, MCFA, essential oils demonstrate some ability
to reduce PEDV RNA, but is ingredient dependent– Effectiveness against infectivity must be validated and feasible
concentrations determined• Multiple preventive and proactive strategies may need to be
employed to maximize PEDV control
Take Home Messages
Partners in PEDV Research• K-State Applied Swine Nutrition Team– Drs. Schumacher, Dritz, Woodworth, Tokach, DeRouchey,
and Goodband; Jordan Gebhardt• K-State Grain Science– Drs. Jones, Stark, and Huss; Roger Cochrane
• K-State VDL– Drs. Hesse, Bai, Haus, Anderson, and their team
• Iowa State University VDL– Drs. Main, Zhang, Gauger, and their team
• National Pork Board, USDA