Industry guidance on monitoring and control of microbial ... · and control of microbial contamination in the aviation fuel ... IATA limit values as such are not appropriate ... Procedures

Industry guidance on monitoring and control of microbial contamination in the aviation fuel supply chain

DLA Energy Worldwide Energy ConferenceGaylord Convention CenterApril 11th 2017

Leon O’Malley, Ph.D

Laboratory Manager

ECHA Microbiology Ltd.

United Kingdom

©ECHA Microbiology Ltd. 2017Results that count

Presentation overview

� Microbiological Contamination

◦ Overview of problem

◦ Options for control

� Monitoring

◦ Field based monitoring

◦ Ideal properties of

testing methods

◦ Available test method overview


Microbiological Contamination


The Microbial Growth Triangle


WATER

MICROBES

FOOD;

• Fuel & Oil• Additives• Other Contaminants

MICROBIAL GROWTH

SPOILAGE &

CORROSION

Control !!

Types of Microorganisms

All types may be involved in a single

incident, simultaneously

or in succession.


10 mm bar

Bacteria Yeasts Molds

Fungi

Manifestation of the Problem

©ECHA Microbiology Ltd. 2017

Results that count

Pitting Corrosion by SRB in Fuel Pipe

Biofilm on Tank Surfaces“Leopard Skin” SpottingOf Fuel Coalescer Elements

Slime in Jet A-1 Storage Tank

Monitoring


Risk Based Routine Monitoring

◦ IATA recommends limit values for microbiological contamination in aircraft fuel tanks.

◦ IATA limit values as such are not appropriate in the fuel supply chain;

e.g. A heavy contamination from a sump sample in a supply tank is not necessarily a confirmation that fuel supply is unfit for service.

JIG Bulletin 83 / Technical Information Document recommends;

1. Evaluate “normal” background levels; • e.g. Initial testing program over 1 - 2 years.

2. Monitor for change;

• Routine testing at defined sample points and frequencies according to risk assessed from;• Initial testing.

• Operational experience.• Operating conditions (temperature, humidity, risk of water

ingress etc.).






Item Sampling location Sampling Frequency

High risk facilities Moderate risk facilities

Low Risk facilities

Fixed Storage Tanks

Storage Tank sump

drain line or dead

bottom sample

Monthly 3 - 6 monthly

advisable.

Annual monitoring after

initial (at least) quarterly

screening for 12 months

to determine background

contamination level

Product Recovery Tanks

Storage Tank sump drain line or dead bottom sample

Monthly 3 monthly. Quarterly where visual

inspection is not possible

Defuelling Vehicle Vehicle Tank sump drain line

Monthly 3 monthly 6 monthly for vehicles

routinely used for

defuelling


� When interpreting results always consider;

◦ Trends,

◦ Operational data / experience


Monthly test of tank bottom fuel by ASTM D7978

Visual Assessment is the Primary Check

• Best Samples are Tank Bottoms, Filter Sump, Low Point etc.

• However, significant microbial contamination may not always be seen!


“Cling film” like lacy material

(bacterial polysaccharide) at fuel - water

interface.

Fungal Growth at the

fuel-water interface for Jet A-1 fuel

Spore (hydrophobic)

Further Contamination

Ideal Properties of a (Field) Microbiological Test Method

� Reliable � Reproducible◦ ASTM Precision Statement

� Sensitive ◦ Detection Limits

� Wide Range of Detection◦ Bacteria, Yeasts, Moulds

(SRB)

� Cost effective� Rapid◦ Relatively Speaking


Training required?

IATA Recommended Test Kits for Aircraft Operators

Fuel and Water Phase

� ASTM D7978 (MicrobMonitor2)◦ Growth Method in Nutrient Gel

� ASTM D7463 (Hy-Lite Jet A-1) ◦ ATP detection by Bioluminescence

� ASTM D8070 (Fuelstat Resinae PLUS)◦ Immunoassay type method

Water Phase only

� Dip –slides◦ San-AI Biochecker FC (Bacteria and Fungi)

◦ Easicult TTC (Bacteria)

◦ Easicult M (Fungi)

◦ Only approved for WATER samples!

©ECHA Microbiology Ltd. 2017

Results that count

ASTM D7978 (ECHA Microbiology MicrobMonitor2 ®)

� Technology

◦ Growth of Microorganisms in Nutrient Gel

and Counting of Resultant Colonies

� Detects

◦ Bacteria, Yeasts, Mold Growth, Spores

� Equipment

◦ Basic Incubator

� Speed

◦ 1 to 4 days

� Units

◦ CFU/L


ASTM D7463 (Merck Hy-Lite® Jet A-1)

� Technology

◦ ATP Detection in Water Phase or Water

Drops by Extraction Method

� Detects

◦ Bacteria, Yeasts, Mold Growth (not Spores)

� Equipment

◦ Meter

� Speed

◦ < 10 minutes

� Units

◦ Relative Light Units


Laboratory Reference Methods

� Filtration methods IP 385 and ASTM D6974 (technically similar) are considered by IATA to be the reference methods.

� Microscope methods can be used for investigation

◦ eg Light Microscopy or fluorescent microscopy using stains/probes (FISH).

� Molecular based profiling methods to assess microbiological

diversity


Molecular Methods


Culture Sequencing

Standardized method between labs

Many elements may differ e.g. DNA

extraction, PCR primers

etc.

Bacteria and Fungi Bacteria (and Fungi possible, but needs the

correct target gene)

Identification requires many manual isolation

steps

Less time required (Once methodology optimised)

Live Microorganisms Live and Dead Microorganisms

Limited Spectrum of Microorganisms

Wider Spectrum of Microorganisms

Percentage of so-called “unculturables”?

Comparison of Culture and Sequencing Techniques

� Culturing can detect a significant proportion of microbial

contaminants

� Power of molecular methods for investigative work


Cultivation DGGE Pyrosequencing

a-proteobacteria 13.8 % 3.9 % 6.6 %

b-proteobacteria 21.1 % 19.2 % 45.0 %

g-proteobacteria 42.8* % 53.9 % 32.1 %

Bacilli 11.8 % 15.4 % 5.1 %

Total 89.5 % 92.4 % 88.8 %

* High Pseudomonas

White et al (2011) AEM Vol 77 (13) p. 4527

Denaro et al (2005) Wright-Patterson Air Force Base/Uni of Dayton

Direct PCR Cultivation Both

61.9% 4.8% 33.3%

References

Aviation Fuel Industry Guidance

Aircraft fuel tanks

� IATA Guidance Material on Microbiological

Contamination in Aircraft Fuel Tanks

◦ 5th Edition December 2015.

Aviation Fuel Supply Chain - US

� API RP 1595 Design, Construction, Operation,

Maintenance, and Inspection of Aviation Pre-Airfield

Storage Terminals.

◦ 6 month check of storage tank bottoms by microbial test.

� A4A 103 Standards for Jet Fuel Quality Control at Airports.

◦ Microbial testing recommended if there are indicators of

microbial growth (e.g. during tank inspection).


References

Aviation Fuel Industry Guidance

Aviation Fuel Supply Chain – RoW (EI/JIG)

� EI / JIG 1530 Quality Assurance Requirements for the

Manufacture, Storage and Distribution of Aviation Fuels to

Airports.

� JIG Guidelines for Aviation Fuel Quality Control & Operating

Procedures for Into-plane Fuelling Services (JIG 1), Airport

Depots (JIG 2) and Smaller Airports (JIG 4).

� JIG Bulletin 83 and Technical Information Document issued

October 2015


Thank you for your attention!!


Documents

Industry guidance on monitoring and control of microbial ... · and control of microbial contamination in the aviation fuel ... IATA limit values as such are not appropriate ... Procedures