A Novel Plasma Treatment System for Disinfection of Pharmaceutical Products

1
A Novel Plasma Treatment System for Disinfection
of Pharmaceutical Products

• Eoin Byrne
• Dublin Institute of Technology
• School of Food Science and Environmental Health
• Supervisors Dr. Vasilis Valdramidis and Dr. PJ
  Cullen

Dr. Kevin Keener
Dr. J.P. Mosnier, J. Connolly
2
Outline

• Introduction
• Disinfection
• Plasma
• PK-1 Device
• Methodology
• Results
• Discussion
• Conclusion

3
Disinfection

• Removal of microbes from inanimate surface
• Used in water processing, food and pharmaceutical
  industries
• Most types of non-sterile products are not
  disinfected before packaging

4
Plasma

• Ionised Gas
• Fourth state of matter
• Highly Conductive
• Constitutes 99 of the universe although limited
  occurrence on Earth

5
Types of Plasma

• Thermal (Hot) Plasma
• Non-thermal (Cold) Plasma
• Can be generated in atmospheric conditions
• Generation of non-thermal plasma
• Radio Frequency
• Microwave Frequency
• Dielectric Barrier Discharge
• Type of gases
• Helium gas
• Nitrogen/Oxygen Mixtures

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Plasma

• Mode of Microbial Inactivation
• Production of radical species
• Production of ultraviolet light
• Physical damage to microbial cell

Scanning electron micrograph image of E. coli
after plasma treatment (X10,000)
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PK-1 Device

• PK-1 is a Dielectric Barrier Discharge Device
• Previously demonstrated microbial inactivation in
  food treatment
• Application for in-package treatment
• Uses two electrodes coated with PVC
• Low power consumption

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Objectives

• Investigate the effect of plasma on microbial
  resistance
• Assess the microbial survival during storage
• Investigate the effect on microbial inactivation
  of helium and air

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Methodology
1.
2.
3.
Surface inoculation of agar-agar plates and
placement in plastic bags
Inoculum preparation (18 hours)
Centrifugation (X3 10,000 rpm)
4.
5.
Plasma treatment 5min ? storage _at_ 1.5, 3, 18, 21
and 24 hours
Serial dilutions and plating on TSA agar followed
by incubation at 37oC/48 hours
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Methodology Step 3

• Agar-agar plates inoculated with Listeria innocua
• Samples placed into plastic resealable bags and
  filled with helium gas or air

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Methodology Step 4
Diagram of the in-package system during plasma
treatment
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Methodology an example
Example of plasma streaming during treatment of
an apple
13
Plasma diagnostics
Optical emission spectrum of air/helium DBD
plasma measured under low resolution conditions
ICCD images of air/helium plasma in a dielectric
barrier discharge
14
Results
Effect of helium generated plasma
Effect of air generated plasma
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Results
Graph showing log reduction of L. innocua after
plasma treatment using air
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Results
Graph showing log reduction of L. innocua after
plasma treatment using helium
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Discussion

• Difference between the consistency of the plasma
  treatment using helium or air
• Most microbial inactivation occurred within 1.5
  hours
• A 2 log reduction in the population of
• L. innocua using the PK-1 device is possible

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Conclusion

• The PK-1 device is capable of microbial
  inactivation after packaging
• Helium produces a more consistent inactivation
  curve during plasma treatment than air
• The PK-1 system has potential in pharmaceutical
  industry

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A Novel Plasma Treatment System for Disinfection
of Pharmaceutical Products

• Eoin Byrne
• Dublin Institute of Technology
• School of Food Science and Environmental Health
• Supervisors Dr. Vasilis Valdramidis and Dr. PJ
  Cullen

Dr. Kevin Keener
Dr. J.P. Mosnier, J. Connolly