MYCOTOXIN RESEARCH AT ESR
Peter Cressey
Institute of Environmental Science and
Research
November 2010
Specialist Science Solutions
Manaaki Tangata Taiao Hoki
protecting people and their environment through science
Geography and Mycotoxins – New
Zealand and Australia
TROPICAL
SUB-TROPICAL
TEMPERATE
© ESR 2008
Imports of Some Potentially
Mycotoxin-containing Foods (ex-FBS
2003)
200%
% of Domestic Supply
New Zealand
150%
Australia
100%
50%
0%
Wheat
© ESR 2008
Maize
Rye
Peanut
Spices
Background - Mycotoxins
• Toxic secondary metabolites of
fungi, particular species of
Fusarium and Aspergillus
• Major mycotoxins of concern
internationally include;
aflatoxins, ochratoxins,
trichothecenes (T-2, HT-2,
nivalenol, deoxynivalenol),
fumonisins, zearalenone, ergot
alkaloids, patulin
• Most important host plant
species are cereals and
seeds/nuts (except for patulin –
apples)
© ESR 2008
Mycotoxins reported in domesticallygrown food
New Zealand
Australia
Aflatoxins
X

Ochratoxins


Trichothecenes


Fumonisins
??

Zearalenone


Ergot
??
??
Patulin


© ESR 2008
The Food Regulatory System in New
Zealand and Australia
JOINT FOOD STANDARDS
© ESR 2008
The Food Regulatory System in New
Zealand and Australia
IMPLEMENTATION AND ENFORCEMENT
AUSTRALIAN
STATES AND
TERRITORIES
© ESR 2008
Previous Food Standards - Mycotoxins
(Australian) Food Standards Code
• Aflatoxin – 0.015 mg/kg in peanuts and peanut
products, 0.005 mg/kg in all other foods
• Ergot – Not detectable in 2.25 litre of grain
• Phomopsin – 0.005 mg/kg in any food
New Zealand Food Regulations
• Aflatoxin – 0.015 mg/kg in peanuts (shelled) and
peanut products, 0.005 mg/kg in all other foods
© ESR 2008
Joint Food Standards - Mycotoxins
• Aflatoxins
-
Peanuts and peanut products
Tree nuts and tree nut products
0.015 mg/kg
0.015 mg/kg
• Phomopsins
-
Lupin seeds
0.005 mg/kg
• Ergot
-
Cereal grains
500 mg/kg
Guiding Principle:
“MPCs will be established for primary commodities
which provide, or may potentially provide, a significant
contribution to the total dietary contaminant intake”
© ESR 2008
Mycotoxin Standards - Rationale
• Aflatoxins – potent mutagens/carcinogens,
peanuts/nuts major source of exposure – ALARA
• Phomopsins – (rodent) liver toxin/carcinogen,
lupins only recognised source – ALARA
• Ergot – highly toxic at high exposure, but
generally controlled by modern agriculture and
processing. Concerns appear to relate to
importation of rye from the Northern Hemisphere
Phomopsins and ergot were regulated in the
previous Australian standards, but not the
previous New Zealand Regulations
© ESR 2008
Mycotoxins for which no Standard was
set
• Ochratoxins – “insufficient data available to
establish whether there is a risk to public health”
• Fusarium toxins – “further survey work is now
being conducted……risk assessment on these
toxins therefore will be finalised when this data
become available”
• Patulin was not considered
© ESR 2008
Other Mycotoxin Activity – New
Zealand
• Older surveys on aflatoxins (1977, 1991, 1999,
2000), ochratoxins (2000), trichothecenes (19892002), zearalenone (1986-1996), patulin (1981,
1998)
• Aflatoxin M1 is included in the annual dairy
residue survey
• 2005/2006 – Risk profiling of mycotoxins in New
Zealand food supply – the current state of
knowledge
• Identified priority data gaps
© ESR 2008
Industry Focus
• Both countries moving to a system where the
food producer/processor/importer/retailer is
responsible for identifying and managing risks
associated with food
• Food Control Programmes/Food Safety
Programmes will be audited to determine
compliance
• Some evidence for this happening for mycotoxins
in some industries (ENZA – patulin, PCA –
aflatoxins)
© ESR 2008
Mycotoxin Research at ESR
• Detection/Measurement
• Risk assessment/risk prioritisation
• (Influence of processing)
© ESR 2008
Measurement of Mycotoxins at ESR
Focus on:
• Aflatoxins. Regulatory and research.
Immunological methods → HPLC → LCMS/MS/MS
• Ochratoxin A. Research. HPLC
• Patulin. Research. HPLC
• Deoxynivalenol. Research. HPLC
Intention to move to multi-mycotoxin LC-MS/MS/MS
methods
© ESR 2008
Mycotoxin Activity – New Zealand
• Older surveys on aflatoxins (1977, 1991, 1999,
2000), ochratoxins (2000), trichothecenes (19892002), zearalenone (1986-1996), patulin (1981,
1998)
• Aflatoxin M1 is included in the annual dairy
residue survey
• 2005/2006 – Risk profiling of mycotoxins in New
Zealand food supply – the current state of
knowledge
• Identified priority data gaps
© ESR 2008
Mycotoxin Risk Ranking or ‘What can I
do without data?’
• The risk profiling exercise carried out in 20052006 sought to prioritise mycotoxins for further
action on the basis of risk
• However, in many cases little information was
available to generate New Zealand-specific risk
estimates
• So, how can be make quanitative decisions with
quantitative data?
© ESR 2008
Risk Assessment
•
•
•
•
Hazard Identification (toxicology, epidemiology)
Hazard Characterisation (toxicology, epidemiology)
Exposure Assessment
Risk Characterisation
© ESR 2008
Hazard Identification (Strength of
Evidence)
Human Health
endpoint
Tox
Epi
Aflatoxins
Primary Liver
Cancer
High
Medium-High
Ochratoxins
Nephrotoxicity
Medium
Medium-Low
Trichothecenes
Gastroenteritis
Haematotoxicity
High
High
Fumonisins
Gastroenteritis
Cancer
Neural tube
defects
Medium
Medium
Zearalenone
Hormonal effects Medium
Low
Ergot alkaloids
Ergotism
High
High
Patulin
???
MediumLow
Low
© ESR 2008
Hazard Characterisation
Type of
exposure limit
Value (mcg/kg Authority
bw/day)
Aflatoxins
Cancer
potency
0.01 (for 10-6
excess risk)
JECFA
Ochratoxins
PTDI
PTWI
TDI
0.0012-0.0057
0.014
0.005
Canada
JECFA
Nordic
Trichothecenes
DON
NIV
T2/HT2
PMTDI/TDI
t-TDI
PMTDI/TDI
1
0.7
0.06
JECFA/EU
EU
JECFA/EU
Fumonisins
PMTDI/TDI
2
JECFA/EU
Zearalenone
PMTDI/t-TDI
0.5/0.2
JECFA/EU
Ergot Alkaloids
-
-
-
PMTDI
0.4
JECFA
©Patulin
ESR 2008
Foods Typically Contributing to Dietary
Exposure
Aflatoxins
Peanuts, maize
Ochratoxins
Bread, cereals, dried fruit,
wine
Trichothecenes
Maize, wheat, beer
Fumonisins
Maize
Zearalenone
Maize, wheat
Ergot Alkaloids
Rye, wheat, barley, triticale
Patulin
Apple juice and apple
products
© ESR 2008
Dietary Exposure Assessment
• Little information available on mycotoxin
exposure in New Zealand
• Available estimates based on fragmentary data
• But, some good estimates available from
comparable countries (i.e. temperate climate, nett
grain importers)
• Can use these data to estimate limits on dietary
exposure
© ESR 2008
Percent of critical limit
Risk Characterization – Lower Limit
© ESR 2008
100
90
80
70
60
50
40
30
20
10
0
AFLA
OTA
DON
NIV
FUM
ZEA
EA
PAT
Risk Characterisation – Upper Limit
200
180
160
140
120
100
80
60
40
20
0
AFLA
© ESR 2008
OTA
DON
NIV
FUM
ZEA
EA
PAT
Risk Ranking (Qualitative)
Risk Group
Mycotoxins
High
(Aflatoxins), Ochratoxin A
Medium
(Fumonisins), Deoxynivalenol,
nivalenol
Low
T2/HT2, Zearalenone, Ergot
Alkaloids, Patulin
© ESR 2008
How do we make Risk Decisions in the
Absence of Data?
Safety Limit - PTWI
What is the level of
population
exposure?
Exposure
© ESR 2008
Exposure/Risk Assessment Refinement
© ESR 2008
Ochratoxin A (OTA) in New Zealand
• In 2005, few New Zealand specific data available
• Plentiful data from climatically similar areas
(Europe)
• Also a range of safety limits defined for OTA
• Used data to define best and worst case
estimates for OTA exposure in New Zealand
© ESR 2008
OTA – Screening Exposure Assessment
200
180
160
140
120
Percent of
100
safety limit
80
60
40
20
0
Best
Worst
OTA exposure
© ESR 2008
OTA Screening Exposure Assessment
• Worst case estimates indicate potential for New
Zealanders to exceeding the safety limit (PTWI)
for OTA
• OTA became a priority for further action in New
Zealand
• Involved identification of priority foods and
design of surveys to determine the OTA content
of foods
© ESR 2008
OTA prevalence
Percent of samples containing OTA
100
2000
2007
2009
50
0
Bread
© ESR 2008
Cereals
Coffee
Dried
Fruit
Spices
New Zealand – Ochratoxin A
Concentrations in Selected Foods
90
Percent of positive samples
80
70
60
50
40
30
Spices
Dried Fruit
20
Coffee
10
Cereals
0
< 0.2
Bread
0.2 - 3.0
OTA Concentration (ppb)
© ESR 2008
>3.0
New Zealand – OTA Exposure
• Initial calculation of chronic exposure based on:
-
Concentration data from 2007 and 2009 surveys
Consumption data from simulated diets (bread, cereals
and coffee), nutrition surveys (dried fruit) and import
data (spices)
• Estimated exposure for adult male – 2.7 ng/kg
bw/day (19 ng/kg bw/week)
• Equates to 17% of PTWI (JECFA – 112 ng/kg
bw/week)
• Doesn’t consider extreme consumers or children
© ESR 2008
Aflatoxins – What Foods are Important
in New Zealand?
Foods of concern are those that are commonly
eaten and/or commonly contaminated with
aflatoxins and/or may contain very high
concentrations of aflatoxins
• Corn/maize (2008)
• Peanuts and peanut products (2010)
• Tree nuts and tree nut products (2010)
• Dried fruit (2009)
• Spices (2009)
© ESR 2008
© ESR 2008
Snack bars
Ginger
Curry powder
ayenne/Chilli/Paprika
Dried apricots
Prunes
Dried vine fruit
Figs
Corn chips
Breakfat cereals,
Mixed nuts
Pistachios
Cashews
Brazil nuts
Almonds
Peanut sauces
Peanut butter
Peanuts
Percent of samples
Aflatoxin (total) prevalence
100
50
0
New Zealand – Aflatoxin
Concentrations in Selected Foods
100
90
80
70
Snack bars
Ginger
Curry powder
ayenne/Chilli/Paprika
Dried apricots
Prunes
Figs
Breakfat cereals, cornflakes
Mixed nuts
Pistachios
Brazil nuts
Peanut sauces
Peanut butter
Peanuts
60
50
40
30
20
10
© ESR 2008
>5.0
AFT
Concentration
1.0-5.0
<1.0
0
What Does this Mean with Regards to
Risk
• Aflatoxins are present in a number of foods
consumed by New Zealanders
• Differing prevalence and concentrations
• Some foods more commonly eaten than others
• Some foods eaten in larger portions than others
Dietary exposure assessment allows integration of
all these factors – are currently carrying out
dietary exposure assessment for aflatoxins
© ESR 2008
Influence of Food Processing
The normal processing of crops to produce foods
eaten by humans can have a significant impact
on the mycotoxin content e.g.
• Roasting of peanuts can reduce the aflatoxin
content by 50-80%
• Wet milling of maize reduces aflatoxin levels to
less than 1% of the levels in the raw grain
• Cleaning of wheat removes 44% of OTA
contamination
• Breadmaking reduces DON levels by up to 60%
© ESR 2008
Influence of Food Processes – OTA in
breadbaking
35
30
OTA (mcg/kg)
25
20
15
10
5
0
Dough before
fermentation
© ESR 2008
Dough after
fermentation
Baked bread
Toasted bread
© ESR 2008