Heat Treatments Paul Fields Cereal Research Centre, Winnipeg - - PowerPoint PPT Presentation

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Heat Treatments Paul Fields Cereal Research Centre, Winnipeg - - PowerPoint PPT Presentation

Jan 27, 2023 303 likes •936 views

Heat Treatments Paul Fields Cereal Research Centre, Winnipeg pfields@agr.gc.ca www.agr.gc.ca/science/winnipeg/cgs_e.htm Overview History and biology of heat treatments Basics of a heat treatment Heat treatment at Quaker Oats

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SLIDE 1

Heat Treatments

Paul Fields

Cereal Research Centre, Winnipeg pfields@agr.gc.ca www.agr.gc.ca/science/winnipeg/cgs_e.htm

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SLIDE 2

Overview

  • History and biology of heat treatments
  • Basics of a heat treatment
  • Heat treatment at Quaker Oats
  • Treatment using propane heaters
  • Treatment using portable steam heaters
  • Spot treatments with heat
  • Heat with other methods
  • Heat safety
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SLIDE 3

History of Heat Treatments

  • 1762, France: 69oC / 156 oF for 3 d, moth
  • 1860, England: 57oC / 135 oF for grain
  • 1910, USA: heat treatment of mills
  • 1920, USA: 30 mills use heat in OH, PA
  • 1932, France: MB as insecticide
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SLIDE 4

History of Heat Treatments

  • 1950’s: Quaker Oats using heat
  • 1983: EDB banned
  • 1990’s: increased interest in heat
  • 1992: MB found ozone unfriendly
  • 1994: Dursban in Cheerios
  • 2005: MB to be phased out
  • 2006: MB one-year extension US, Canada
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SLIDE 5

Temperature Effects

Temperature (°C) Temperature (°F)

  • 30
  • 20
  • 10

10 20 30 40 50 60 70

  • 20

20 40 60 80 100 120 140

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SLIDE 6

Mechanism of Heat Death

  • 40-50 oC / 105 to 120 oF dehydration

important

  • Above 50 oC / 120 oF
  • Cell membranes “melt”
  • Damage to enzymes
  • Change in salt balance
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SLIDE 7

Time/temperature to control insects

  • 24 h at 38ºC / 100oF
  • 12 h at 43ºC / 110oF
  • 5 min at 50ºC / 120oF
  • 1 min at 55ºC / 130oF
  • 30 sec at 60ºC / 140oF
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SLIDE 8

Mortality of adults exposed to heat

Mortality (%) Insect

50oC / 120 oF, 20 s 50oC / 135 oF, 32 s

Cigarette beetle 35 99 99 97 98

98

94 100

97

98 Flat grain beetle 45 Lesser grain borer 45 Rice weevil 60

Red flour beetle 60

Granary weevil 70 Merchant grain beetle 85

Confused flour beetle 90

Saw-toothed grain beetle 97

Kirkpatrick and Tilton 1972

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SLIDE 9

Differences Between Insects

  • Below 50oC / 120oF differences
  • Above 50oC / 120oF all very similar
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SLIDE 10

Overview

  • History and biology of heat treatments
  • Basics of a heat treatment
  • Heat treatment at Quaker Oats
  • Treatment using propane heaters
  • Treatment using portable steam heaters
  • Spot treatments with heat
  • Heat with other methods
  • Heat safety
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SLIDE 11

Heat Disinfestation

  • 50oC / 120oF for 24 h
  • has been used in US-Canada since 1950’s
  • Need heat-tolerant equipment
  • Can be done by plant personnel
  • Need heat source
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SLIDE 12

Protect unheated areas

Spray with approved contact insecticide to prevent insects from moving into cool areas

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SLIDE 13

Clean-up

Remove harborages for insects

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SLIDE 14

Steam Heat

Fixed heaters Mobile boilers Fixed boilers Portable heaters

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SLIDE 15

Gas Heaters (propane or natural)

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SLIDE 16

Electric Heaters

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SLIDE 17

Variation in floor temperatures during heat-treatment

  • f a flour mill

Dowdy 1999

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SLIDE 18

Ways to move heat

Wire and plastic duct Fabric duct

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SLIDE 19

Air circulation important

Fans or circuits may overheat

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SLIDE 20

Measuring Temperatures

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SLIDE 21
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SLIDE 22

Measuring Temperature

  • Measure hourly, several locations/floor
  • Determines if too hot or too cool
  • Be consistent from treatment to treatment
  • Keep records
  • Infra guns can lose calibration in heat
  • No glass thermometers in food plants
  • Have spare batteries
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SLIDE 23

Overview

  • History and biology of heat treatments
  • Basics of a heat treatment
  • Heat treatment at Quaker Oats
  • Treatment using propane heaters
  • Treatment using portable steam heaters
  • Spot treatments with heat
  • Heat with other methods
  • Heat safety
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SLIDE 24

Heat Treatment at Quaker Oats (Peterborough, Canada)

  • Sprinklers with 85 or 100oC

185 or 210 oF heads

  • Buys equipment to handle heat
  • Uses steam heaters
  • Building mix of old and

new; wood, brick and concrete

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SLIDE 25

Heat Treatment at Quaker Oats

  • Friday Morning
  • Shut down lines
  • Clean up
  • Leave machines open
  • Remove heat sensitive ingredients/equipment
  • Loosen belts
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SLIDE 26

Heat Treatment at Quaker Oats

  • Friday Afternoon
  • Close doors and

windows

  • Start heaters
  • Finish cleaning,

removal of materials

Steam heater with powerful fan

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SLIDE 27

Heat Treatment at Quaker Oats

  • Friday Evening
  • Monitor air temperature at

eye level in 4 corners of each room once an hour

  • Check building during

temperature monitoring

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SLIDE 28

Heat Treatment at Quaker Oats

  • Saturday
  • Shut off fans in areas that have obtained

50oC / 120oF for 24 h in all 4 corners

  • Continue to monitor temperature
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SLIDE 29

Heat Treatment at Quaker Oats

  • Sunday Morning
  • Open windows and doors for cool down
  • Replace heat sensitive materials
  • Tighten belts
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SLIDE 30

120 oF 140 oF 100 oF

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SLIDE 31

Heat Treatment at Quaker Oats

  • Lines shut down for 48 h
  • Treatment done by plant staff
  • Need 50-55oC/120-130oF for 24 –30 h
  • Done 4-6 times a year
  • Use down-time for inventory
  • Use steam heat from cooking boilers
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SLIDE 32

Overview

  • History and biology of heat treatments
  • Basics of a heat treatment
  • Heat treatment at Quaker Oats
  • Treatment using propane heaters
  • Treatment using portable steam heaters
  • Spot treatments with heat
  • Heat with other methods
  • Heat safety
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SLIDE 33

Temp-Air Propane Heaters: Mill 1

Propane, forced air heater

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SLIDE 34

Insect Bioassay: Red Flour Beetle; eggs, larvae and adults

Insects pulled at end of treatment, many locations Insects pulled every 1 to 2 hours, one location

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SLIDE 35

Mill 1: Temp-Air

  • Mill Shut down: 60 hours
  • Heater type: propane, 7 heaters used
  • Heaters On: 30.5 hours, 20 million BTU/hr
  • Cost of propane: $6,000 CND
  • Temperature Highs: 58-73 oC /136-163 oF
  • All insects dead at one location after 8.5 h
  • 100% mortality of red flour beetle adults in 20
  • f 20 locations
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SLIDE 36

Temperature: Mill 1 with Propane

Temperature (0C)

20 30 40 50 60 70 12:00 18:00 06:00 12:00 18:00 06:00 Sunday, August 31 Saturday, August 30

Temperature (0F)

80 90 100 110 120 130 140 150 160

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SLIDE 37

Problems Mill 1

  • Fans cut-out due to circuit breaker becoming too hot

(breakers in heated area, changed breakers to higher amperage during heat treatment)

  • Some caking of flour in equipment (minor problem)
  • One air hose line burst (air pressure should have

been off during treatment)

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SLIDE 38

Roo-Can Steam Heaters: Mill 2

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SLIDE 39

Roll heaters into mill

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SLIDE 40

Steam Heating: 18 heaters used

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SLIDE 41

Mill 2: Roo-Can

  • Mill Shut down: 30 hours
  • Heaters: steam, 18 heaters used, 3 million BTU/hr
  • Heaters On: 21 hours (3h shorter than initial plan)
  • Cost of Steam: $300 CDN
  • Temperature Highs: 46-74 oC / 114-165 oF
  • All insects dead at one location after 13 h
  • 100% mortality of red flour beetle adults in 21 of 25

locations

  • Mill management “More time, or more heaters would be

required to get control in all locations”

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SLIDE 42

Temperature: Mill 2 with Steam

Temperature (0C)

20 30 40 50 60 70 12:00 18:00 06:00 12:00 18:00 06:00 Sunday, September 7 Saturday, September 6

Temperature (0F)

80 90 100 110 120 130 140 150 160

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SLIDE 43

Problems: Mill 2

  • Some leaking of condensate on one floor

(pump failure in basement)

  • Some rented fans stopped working due to
  • verheating
  • Not total kill of insects in bioassays, or in mill
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SLIDE 44

Flour beetles caught in dome traps.

Methyl bromide fumigation on July 26-27.

Flour beetles as percent of pre-treatment (%) Pre-Treatment Post-Treatment 15 July 22 July 25 July 29 July 5 Aug 8 Aug 18 Aug 25 Aug 2 Sept 9 Sept 16 Sept 23 Sept

Roller Floor

136 104 60 20 1.1 4.3 2.1 1.5 0.7 0.4 0.7 2.6

Sifter Floor

134 60 106 7.5 1.4 4.3 Site

10 Dome traps used/floor

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SLIDE 45

Flour beetles in dome traps.

Mill 1: Temp-Air heat treatment took place on August 29-31.

Flour beetles as percent of pre-treatment (%) Pre-Treatment Post-Treatment

25 Jul 1 Aug 8 Aug 18 Aug 25 Aug 29 Aug 8 Sept 15 Sept 22 Sept 29 Sept 6 Oct 17 Oct

Roller Floor 67 74 105 71 110 201 13 9 17 15 27 17 Sifter Floor 37 65 77 68 140 245 4.5 5.7 7.4 5.7 6.2 7.6

Site

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SLIDE 46

Conclusions

  • Good control of insects by heat treatments
  • No major damage to equipment
  • Good method to locate insect problems in

mill

  • Mills shut down 30 to 60 hours
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SLIDE 47

Overview

  • History and biology of heat treatments
  • Basics of a heat treatment
  • Heat treatment at Quaker Oats
  • Treatment using propane heaters
  • Treatment using portable steam heaters
  • Spot treatments with heat
  • Heat with other methods
  • Heat safety
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SLIDE 48

Spot or Portable Heating

  • Spot heating of equipment
  • Heat finished product
  • Trailer
  • On production line with longwave radiation
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SLIDE 49

tarpaulin heat ducts roll stand

Spot Heat Treatment of Roll Stand in Swedish Flour Mill

Input: 93 oC / 200 oF Outside propane heater Roll stand: 60 oC /140 oF Duration: 4 h

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SLIDE 50

Long wave radiation

  • 27 MHz wavelength
  • penetrates 15- 20 inches

(microwave only 4 inches)

  • 900 lbs/hr
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SLIDE 51

Heat Final Product

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SLIDE 52

Heat and other control methods

  • Heat and DE
  • Heat, phosphine and CO2
  • Heat and ProFume (sulfuryl fluoride)
  • Heat increased effectiveness of Tempo
  • Heat and sampling
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SLIDE 53

Overview

  • History and biology of heat treatments
  • Basics of a heat treatment
  • Heat treatment at Quaker Oats
  • Treatment using propane heaters
  • Treatment using portable steam heaters
  • Spot treatments with heat
  • Heat with other methods
  • Heat safety
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SLIDE 54

Why do insects die at 500C / 1200F, and we just get hot under the collar?

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SLIDE 55

Size Matters

Subi is 40,000,000 X heavier than a red flour beetle

Subi at work in England Red flour beetle

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SLIDE 56

Insect body temperature = environment temperature

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SLIDE 57

Sweat

  • 99% water
  • Salt
  • Urea

2.5 M glands

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SLIDE 58

Types of Heat Stress

  • Heat Exhaustion
  • Heat Cramps
  • Heat Stroke
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SLIDE 59

Tips to Avoid Heat Stress

  • Drink lots of cool fluids often
  • Drink even if you are not thirsty
  • Wear loose clothing
  • Take breaks from heat
  • Elderly, heart problems, overweight low

sodium diet at risk

  • Avoid alcohol
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SLIDE 60

Conclusions

  • 50oC / 120oF for 24 h
  • Has been used in US-Canada since 1950’s
  • Need heat-tolerant equipment
  • Can be done by plant personnel
  • Various heat sources available
  • No regulatory approval needed
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SLIDE 61

Thank-you for your attention