Impact of hauling practices on raw milk quality
Emily Darchuk and Dr. Lisbeth Goddik
Image Source: https://mackinsondairy.files.wordpress.com/2014/11/cows-pasture.jpg
Background
Study Objectives
1. Determine the impact of operating trucks for an extended period of time
(24 hrs and up to 10 loads prior to CIP)
2. Impact of seasonality
3. Impact of different cleaning procedures
Hypothesis:
1) Extended use of tanker trucks will negatively impact raw milk quality
2) Impact will be more pronounced in summer
3) Any impact can be mitigated through intermittent cleaning treatments
3
Study Methodology
4
Study Background
A ) Winter Study
• Short duration and high frequency tanker use
• Up to 9 loads per 24 h with 1-5 farms per load
• Average temp: 37°F
B ) Summer Study
A
B
• Short duration and high frequency tanker use
• Loads averaged 7 per 24 h with 1-3 farms per load
• High temp: 97°F
5
Study Design
• Impact of different cleaning procedures
1.
2.
3.
4.
Standard use ( 24 hr CIP)
Water rinse after each load
Water rinse after each load & sanitizer treatment after 12 hrs
Sanitizer treatment after 12 hrs
• Blocked design to account for variability
• Truck effect
• Sample location (front vs back)
• Day effect
6
Areas of Investigation
Producer Milk
Tanker Milk
Provide baseline milk quality data
Show the effect of hauling
Frequency:
•Sample from every farm bulk
tank loaded into truck
Frequency:
•Sample from the front and back
of every load
Testing :
•Bactoscan (IBC)
•Thermophilic Sporeformer (TSC)
•Preliminary Incubation (PI)
Testing:
•Bactoscan (IBC)
•Thermophilic Sporeformer (TSC)
•Preliminary Incubation (PI)
Tanker Surface
Efficacy of cleaning
Frequency:
•Before and after each treatment
Testing:
•Sponge swabs (APC)
•ATP Swab (post cleaning
treatment only)
7
Study Results
8
Measure of Raw Milk Quality: No impact due to hauling
Winter
Sanitizer
Standard Use (Control)
Water Rinse & Sanitizer
Water Rinse
Difference in Log cfu/mL
0.5
0.25
0
-0.25
-0.5
0
1
2
3
4
5
6
7
8
9
1
2
3
4
Load Number
5
6
7
8
9
1
2
3
4
5
6
7
8
9
1
2
3
4
5
6
7
8
Load Number
Load Number
Water Rinse
Water Rinse & Sanitizer
Load Number
9
Summer
Sanitizer
Standard Use (Control)
Difference in Log cfu/mL
0.5
0.25
0
-0.25
-0.5
0
1
2
3
4
5
Load Number
6
7
8
1
2
3
4
Load Number
5
6
7
1
2
3
4
Load Number
5
6
7
1
2
3
4
Load Number
5
9
6
7
Measure of Cleaning Efficacy and Tanker Sanitation
Plant Swab Data
4
3.5
cfu/900 cm2
3
ATP DATA
PASS < 150 RLU
2.5
2
1.5
1
0.5
0
Plant A
Plant B
Winter
Summer
Pre Rinse
Post Rinse
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Discussion of Results
• Temperature
• All loads arrived <45 °F
• Tanker insulation effective in maintaining cold temperature
• <4 °F per 24 hr
• Time
• All loads had short duration within truck (< 5 hr)
• Dilution
• Limited residual milk left in tanker
• Results are based on test methods used, more sensitive methods may
find issues that could impact quality down stream
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Industry Recommendations
• Continue current hauling practices
• No data to suggest addition of rinses would improve raw milk quality
• Rinses could be used as a preventative measure as it does reduce tanker
surface bacteria
• Focus on conducting scheduled cleans and maintenance of trucks and line
• Collect ATP data post CIP for general trending
• Focus on maintaining high quality producer milk
12
Future Research
• Investigate a more sensitive test methods focused on down stream
quality defects
• Conduct worst case scenario hauling study
• DMI supporting continued hauling research at OSU
Contact : [email protected]
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Acknowledgements
• Washington Dairy Products Commission
• Gina Shellhammer- Statistician
• Dr. Lisbeth Goddik and Dr. Joy Waite-Cusic
14
Thank you !
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