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NEW SANITISING TECHNOLOGIES – WITHOUT CHEMICALS
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Dr. Marie‐Astrid OttenhofTechnical Director, Schreurs & Sons
OBJECTIVES• What made us look for an alternative?
• Reasons for selecting Electrolysed OxidisedWater (EOW)
→ What were we thinking?
• How does EOW work?
• Advantages & disadvantages
• Another alternative… without chemicals
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SCHREURS & SONS• 3rd generation farming business, specialisingin:
• Most of the produce is washed on the farm
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CHLORINE DIOXIDE (ClO2)
• This was used as a trial sanitiser for a triple wash bath system
• ClO2 was a preformed gas
• Dispersed into solution
• Agitation used for washing produce can cause gas to come out of solution… with OH&S consequences…
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ALTERNATIVE SANITATION SYSTEMS
• Dr Robert Premier (Global F.S. Pty Ltd)
Evaluation of Vegetable Washing Chemicals (VG09086) – June 2012
• Compared efficacy of wide array of sanitisingchemicals on leafy veg including:
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PAA Chlorine Chlorobromo
Organics Gas based EOW
ALTERNATIVE SANITATION SYSTEMS
• Washing produce under running potable water can reduce the bacterial level by ~2 log
• Project measured sanitiser efficacy as % change in bacterial count vs water washed produce (control)
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% CHANGE IN SPINACH TPC – WATER VS SANITISER WASHING
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Unipolar 60ppmUnipolar 45ppmUnipolar 20ppmTsunami 40ppm
Tsunami 100ppmSummit 40ppm
Summit 100ppmProxitane 40ppm
Proxitane 100ppmNylate 5ppmCitrox 2.5%
Citrox 1%Citrofresh 2.5%
Citrofresh 1%Chlorine 100ppm
Aussan 2.5%Aussan 1%
Adoxysan N14 40ppmAdoxysan N14 100ppm
Acetic acid 4%Acetic acid 2%
100806040200
Trea
tmen
t
percentage change
Food = spinachIndividual Value Plot of percentage change from water
AND THE WINNER IS…
• EOW → had superior efficacy
–Microbial perspective
– Product shelf life
– No chemical(s) to be added
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HOW DOES EOW WORK?• EOW is created by electrochemical disassociation of water and natural salts
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• A cocktail of sanitiser molecules is generated, incl. HClO, OCl‐, Cl2, H2O2and O3
• The concentration of sanitisermolecules is dependent on the current
EOW UNITS SUPPLIED BY UWT
• UWT = Unipolar Water Technologies
• Originally designed process to treat sewage and industrial effluents
• Technology has been validated in accordance with the Dept of Health VIC guidelines 2013 to inactivate at least 4 log bacteria and viruses
• EOW effective against array of human pathogens
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EOW UNIT
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12 cell unit footprint = ~ 1m x 3m
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START‐UP• Fill recirculating wash bath with water and switch on pumps
• Add ~250g dissolved table salt to assist in electrolysis
• Hit ‘START PLANT’ button
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VARIABLES OF INTEREST• Power supply (amps) – required to start electrolysis
• Water flow (l/min) –flow required through electrodes and bath
• Conductivity (µS/cm) – indicative of salt concentration, target >1100µS/cm
• Chlorine level (ppm) – only measurable sanitiserfrom chemical cocktail produced
• Chlorine Setpoint (ppm) – dependant on HACCP plan
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EXAMPLE OF DATA CAPTURED…
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Date Time Maximum FLOW Rate
Minimum CL2
Minimum EC
Maximum AMPS
1/7/2017 5:39:49 133 3 4 1111/7/2017 5:44:49 135 2 1318 1111/7/2017 5:49:49 135 5 1340 1111/7/2017 5:54:49 134 9 1350 1111/7/2017 5:59:49 134 13 1352 1111/7/2017 6:04:49 133 18 1352 11/7/2017 6:09:49 133 19 1343 11/7/2017 6:14:49 134 19 1344 11/7/2017 6:19:49 133 20 1253 11/7/2017 6:24:49 133 19 1241 11/7/2017 6:29:49 133 19 1260 11/7/2017 6:34:49 133 18 1256 11/7/2017 6:39:49 133 17 1212 11/7/2017 6:44:49 133 16 1137 11/7/2017 6:49:49 133 16 1087 11/7/2017 6:54:49 133 15 1037 611/7/2017 6:59:49 133 11 995 1111/7/2017 7:04:49 133 14 1065 1111/7/2017 7:09:49 134 16 1116 1
... WHEN GRAPHED
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0
20
40
60
80
100
120
0
5
10
15
20
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5:39
:49
5:49
:49
5:59
:49
6:09
:49
6:19
:49
6:29
:49
6:39
:49
6:49
:49
6:59
:49
7:09
:49
7:19
:49
7:29
:49
7:39
:49
7:49
:49
7:59
:49
8:09
:49
8:19
:49
8:29
:49
8:39
:49
8:49
:49
8:59
:49
9:09
:49
9:19
:49
CURR
ENT (AMPS)
CHLO
RINE CO
NCE
NTR
ATION (P
PM)
TIME
Minimum CL2
Maximum AMPS
WHILST THE SYSTEM IS RUNNING• Conduct 3 chlorine test strip checks across production day
Start | Middle | End
• Staff monitor screen regularly
• Warning light comes on when out of spec
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• Chlorine probes calibrated every 4months
SHUT DOWN• Before dumping water, start backwash:
• This cleans electrodes by reverse electrolysis
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ADVANTAGES OF EOWNo chemicals are needed (except table salt to assist electrolysis)
Countries across the globe are beginning to ban chlorine based sanitisers
Any chemical formed reverts back to the same chemical prior to electrolysis in due time
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ADVANTAGES OF EOWCan be used for direct food applications without rinsing
More effective clean versus conventional sanitisers
The system automatically records the chlorine level at a pre‐determined frequency
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Date Time Maximum FLOW Rate
Minimum CL2
Minimum EC
Maximum AMPS
1/7/2017 6:04:49 133 18 1352 11/7/2017 6:09:49 133 19 1343 11/7/2017 6:14:49 134 19 1344 11/7/2017 6:19:49 133 20 1253 1
ADVANTAGES OF EOW
Is automated and continuously produces certain amount of sanitisers
Shelf life of sensitive produce such as baby leaf appears to be better (quality and age) compared to other sanitisers
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ADVANTAGES OF EOWIt is cost efficient to run and operate
Low power consumption 1.0 – 1.5kWh/kL
Runs at ambient temperature and pressure
Cleaning is automated – reverse electrolysis and no chemicals
Short cleaning cycles minimise down time
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DISADVANTAGES
• Initial cost
• If wash water needs changing, the changeover can take ~30‐45min
– Solution: have a tank with electrolysed oxidisedwater ready to go to assist start up dosing
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ANOTHER ALTERNATIVE… WITHOUT CHEMICALS
COLD PLASMA –MORE ELECTRICITY INDUCED
SANITATION
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COLD PLASMA• New, non thermal food processing technology
• Application of electric current to air or a gas
• Reactive gases produced have antimicrobial activity
• Has been used on meats, poultry, fruits and vegetables
COLD PLASMA USES• Proposed for decontamination of fruits & veg... without changes to sensory attributes
• Growing demand for fresh produce• Challenge to food industry to supply safe food with minimal processing
HOW BEST TO DESCRIBE COLD PLASMA?
• Fourth state of matter
• Commonly used method to generate and sustain a low temperature plasma = apply electric field to a neutral gas
Mishra et al. (2016) Cold Plasma: Emerging as the New Standard in Food Safety, Research Inventy: International Journal of Engineering and Science, Vol. 6, Issue 2
HOW DOES IT HAPPEN?• When gas is passed through electrodes, electrons are stripped off the gas and combine with other gases to form sanitising compounds
Mishra et al. (2016) Cold Plasma: Emerging as the New Standard in Food Safety, Research Inventy: International Journal of Engineering and Science, Vol. 6, Issue 2
WHAT DOES IT LOOK LIKE?• Atmospheric plasmas containing high levels of bactericidal molecules (> 100 ppm ozone, nitric oxides, peroxides, etc.) are generated
• Done with minimal power under room‐temperature conditions in seconds to minutes
WHAT DOES IT LOOK LIKE?• Little or no product heating, increases <5°C
• Generate bactericidal molecules in situ efficiently solely from air
• Have teamed up to study cold plasma in the horticultural industry including vegetables
• Contact Project Leader Dr Sukhvinder Pal at the NSW DPI
– http://www.coldplasma.net.au/
THANK YOU
• Dr ROBERT PREMIER – GLOBAL F.S. Pty Ltd
• UNIPOLAR WATER TECHNOLOGIES
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QUESTIONS?
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REFERENCE MATERIAL• ELECTROLYSED OXIDISED WATER:
– Premier, R. (2012) Evaluation of Vegetable Washing Chemicals (VG09086)
– http://unipolar.com.au/
• COLD PLASMA:– Mishra, R. et al. (2016) Cold Plasma: Emerging as the New Standard in Food Safety, Research Inventy: International Journal of Engineering and Science, Vol. 6, Issue 2
– http://www.coldplasma.net.au/
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