Feed Mill Biosecurity: Reducing Risk in the Feed Manufacturing Process

Dr. Jason Woodworth

Kansas State University

Applied Swine Nutrition Team

Biological Hazards & FSMA

• Under FSMA (final rule published Sept. 17, 2015), food animal production plants (feed mills) will need to develop plans to mitigate specific & identified hazards.

• Hazards are defined as “any biological, chemical (including radiological), or physical agent that has the potential to cause illness or injury in humans or animals.”

• Under this definition PEDV could be considered a hazard, but also metal, plastic, mycotoxins, pesticides, etc.

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What is biosecurity?

• Biosecurity is a holistic concept of direct relevance to the sustainability of agriculture, food safety, and the protection of the environment, including biodiversity. FAO

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How important is feed mill biosecurity?

• With PEDV, a dose as low as 200 infectious particles in feed has been demonstrated to result in pig infection (Schumacher, Woodworth, Zhang, Gauger et al., 2015 )

• An acutely infected piglet can produce 100,000,000 infectious particles per gram of feces

• Thus, 1 gram of feces from an acutely infected pig could contaminate up to 500 tons of feed with each gram of feed being infectious

Controlling/Minimizing Hazards & Risk

• Preventing entry at receiving (Laura)

– Supplier verification and trust

– Strong quality assurance procedures

– Stringent quality control upon arrival

• Preventing entry from people/vehicles (Laura)

– Dedicated flows and “isolation” areas

• Preventing cross contamination during production

– Housekeeping schedules

– Separated ingredient and finished product areas

– Feed flushing and sequencing

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Controlling/Minimizing Hazards & Risk • Mitigation of Hazards in the mill

– Dust collection

– Processing (pelleting/temperature)

– Chemical mitigants

• Preventing cross contamination during load-out and delivery – Dedicated load-out areas

– Truck sanitation

– Sequencing loading and delivery

• Assessments (Tim) – Written & detailed biosecurity plan

– Self and/or 3rd party audits/assessments

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With PEDV in mind…Is feed mill contamination a big issue?

• Study conducted at KSU to determine feed mill surface contamination after processing a PEDV-infected batch of feed.

• 3 replications (days) of a batch of PEDV-inoculated feed mixed, discharged through a bucket elevator and then pelleted.

• 4 sequential PEDV-negative batches processed the same way but not pelleted.

• Environmental swabs collected of equipment and facility surfaces after each batch and analyzed via PCR for detection of PEDV.

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O.H. Kruse Feed Technology Innovation Center at Kansas State University

• Cargill Feed Safety Research Center

• 3 story BSL-2 Lab

– Air filtration through HEPA filters

– Negative air-pressure

– Shower-out procedure

– Multi-step decontamination

Equipment: Scaled feed mill 9

Open footprint for flexibility 10

Environmental contamination after processing PEDV-inoculated feed

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0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

100.0Po

siti

ve C

t fo

r P

EDV,

% Zone 1

Zone 2

Zone 3

Zone 1 = direct feed contact surfaces- equipment interiors Zone 2 = surfaces directly adjacent to zone 1 Zone 3 = structural surfaces- floors, walls

Ct of Environmental Swabs

After PEDV diet

After 1st flush diet

After 2nd flush diet

After 3rd flush diet

After 4th flush diet

Direct Feed Contact

Mixer 29.2 33.9 34.9 35.4 34.8

Elevator 30.8 31.8 32.9 32.5 32.1

No Direct Feed Contact

Metal 31.3 31.7 33.4 32.0 33.2

Concrete 33.7 33.9 33.0 32.6 33.2

Rubber 31.9 32.3 33.0 32.7 32.4

The Challenge: Feed mills are a complex system of specialized equipment

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Feed mills are not necessarily designed with biosecurity in mind

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Mill Manager Purchasing Agent

Receiving

Operator

Maintenance

Supervisor

Production

Operator

Shift Supervisor

Load Out

Operator

Formulator

Feed Manufacturing: A network of many people

Veterinarian

Nutritionist

Preventing cross contamination during production and delivery

• Flushing & Sequencing

• NPB Sequencing study

– Process a non-PEDV batch of feed to “charge” the system

– Process a PEDV-inoculated batch of feed

– Follow with 4 sequential non-PEDV batches of feed

– Replicate entire process 3 times (3 days)

– Measure cross contamination by PCR and bioassay

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Sequencing to reduce PEDV Cross Contamination in Feed

After PEDV diet

After 1st seq. feed

After 2nd seq. diet

After 3rd seq. diet

After 4th seq. diet

PEDV Detected in Feed, # of samples

Mixer 9/9 7/9 0 0 0

Elevator 9/9 7/9 2/9 0 0

Ct of Feed when PEDV was Detected

Mixer 31.7 38.1 - - -

Elevator 30.9 37.8 39.0 - -

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Sequencing to prevent PEDV infectivity 18

Item

Feed inoculum 0 dpi 2 dpi 4 dpi 6 dpi 7 dpi

7 dpi Cecum

PEDV detected in pigs, # of pigs

After non-PEDV feed Neg 0/9 0/9 0/9 0/9 0/9 0/9

After PEDV feed Pos 0/9 9/9 9/9 9/9 9/9 9/9

After Sequence 1 Pos 0/9 1/9 3/9 3/9 4/9 3/9

After Sequence 2 Neg 0/9 1/9 3/9 3/9 3/9 3/9

A total of 3 replications/treatment with 3 pigs/replicate

-Sequencing reduced PEDV detection in feed -However, carry over of infectivity did occur -Concerning that infectivity was demonstrated from feed where RNA was not detected (Ct >45)

“Clean” equipment similar to a commercial mill

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Surface contamination was present even when PEDV was not detected in feed

Feed Surface

After: Mixer Elevator Mixer Elevator

Neg Feed 0/9 0/9 0/9 0/24

After PEDV feed 9/9 9/9 9/9 24/24

After 1st sequence 7/9 7/9 9/9 24/24

After 2nd sequence 0/9 2/9 6/9 24/24

After 3nd sequence 0/9 0/9 4/9 24/24

After 4th sequence 0/9 0/9 4/9 24/24

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PEDV detected in feed or surface swabs, # of samples

Preventing cross contamination during production: Housekeeping

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Mitigation of Hazards

• Dust Collection

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DO NOT add back to the

feed!

Mitigation of Hazards • Thermal processing: PEDV is known to be heat

sensitive.

• 2 Studies conducted at KSU to determine if pelleting will impact PEDV survivability – Study 1: Measured the effects of increasing

conditioning temperature (155, 175, 195° F) and time (45, 90, 180 s) on PEDV survivability.

– Study 2: Measured the effect of increasing conditioning temperatures (100, 115, 130, 145, or 160 ° F) on PEDV survivability.

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Study 1: Effect of Conditioning Time and Temperature on PEDv PCR

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Low Dose PCR Ct Values

Time, sec

Temp, F 45 90 180

155 43 40 45

175 37 40 42

195 40 37 36

Low Dose Feed No processing = 31

High Dose PCR Ct Values

Time, sec

Temp, F 45 90 180

155 30 30 30

175 30 30 30

195 30 31 30

High Dose Feed No processing = 24

No infectivity developed from any of the pelleted diets!

Study 2: Pelleting to prevent PEDV survival

Conditioner temperature, ° F

100 115 130 145 160

PEDV Detected in Feed, % of samples

9/9 9/9 9/9 8/9 8/9

Ct of Feed when PEDV was Detected

32.5 34.6 37.0 36.5 36.7

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A total of 3 samples collected from each diet from each of 3 replications

Study 2: Pelleting to prevent PEDV infectivity 26

Feed 0 dpi 2 dpi 4 dpi 6 dpi 7 dpi 7 dpi

Cecum

PEDV detected in feed or pigs, # of samples

No PEDV 0 0 0 0 0 0 0

100°F 9/9 0 1/9 3/9 3/9 3/9 3/9

115°F 9/9 0 3/9 3/9 3/9 3/9 3/9

130°F 9/9 0 0 0 0 0 0

145°F 8/9 0 0 0 0 0 0

160°F 8/9 0 0 0 0 0 0

A total of 3 samples collected from each diet from each of 3 replications

Chemical Mitigation

• Major benefit: Potential residual benefits that could provide protection through feed delivery and at the farm. – Different than pelleting which is a point in time mitigation

step…recontamination can still occur

• Early research suggests that chemical treatment benefits are

ingredient/matrix specific

• Formaldehyde: – Has been shown to be effective by Dee et al. (2014) and Cochrane et

al. (2015)

• Cochrane et la. (2015) also tested other products

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PEDv contamination post-treatment in swine diet stored at Room Temperature

Sow

Feed

Preventing cross contamination during load-out and delivery

• Flushing and sequencing in load out bins and truck compartments.

• Sequencing deliveries from high to low risk and from clean to dirty farms

Finish

Feed Sow

Feed

Sow

Feed

Finish

Feed

Finish

Feed

Use visual verification to ensure compartments are empty.

Preventing cross contamination during load-out and delivery

Use protective foot ware when exiting trucks at sites

Never enter barns!

Clean and disinfect truck cab area regularly!

Preventing cross contamination during load-out and delivery

Preventing cross contamination during delivery

• Consider dedicated feed transport for nucleus, multiplication, and boar studs

• Wash, disinfect and dry before moving up the biosecurity pyramid

• Include cab and floor mats in cleaning protocols

Exhaust fan dust has been shown to contain infective PED virus.

Preventing cross contamination delivery

Conclusions

• Feed mill biosecurity is an evolving concept that involves many people within a complex system.

• Although contamination levels may be low, feed mills are challenging environments to decontaminate.

• #1 goal is to prevent contamination from occurring.

• Feed sequencing, pelleting, & chemical treatment have been shown to be effective mitigation strategies in relation to PEDV.

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Partners for our 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