Transcript No Slide Title

Phytosanitary Treatments for
Fresh Fruits and Vegetables:
The Irradiation Option
2011 AUSVEG Convention
Brisbane, 14 - 16 April, 2011
Speaker Session
Peter B Roberts
Radiation Advisory Services
Lower Hutt, New Zealand
This Presentation – Why Now?

Interstate Certification Assurance National
Protocol (ICA-55)
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A protocol for the use of irradiation as a
phytosanitary treatment for fresh fruits and
vegetables within Australia
Possibility that use of dimethoate and
fenthion will be further restricted or revoked
This Presentation

Irradiation as an industrial process
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Food irradiation in brief

An assessment of irradiation as a
phytosanitary treatment

Trade in irradiated fruits

The future
Irradiation

The major uses of irradiation are for non-food
applications

to sterilise medical products
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over 50% of single-use medical products are irradiated
to cross-link polymers
to sterilise imported items that may harbour human or
plant pathogens, as required by AQIS
These applications have been used since the
1950s
The techniques are very well understood
Food Irradiation
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A physical process, like heating, cooling, drying , canning
and pasteurization
It uses high energy ionising radiation from gamma-rays, xrays or an electron beam
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Gamma rays are produced by a radioactive isotope, usually cobalt60
An electron beam is produced by an electrical machine (an
accelerator). Electrons can be converted into X-rays
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No radiation is produced while the accelerator is switched off
Gamma and x-rays are very penetrating (pallet-sized loads)
Electrons penetrate packages a few centimetres thick
The Process
Hint – think microwaves
Radiation
Source
Food
Cobalt-60
Caesium-137
Electron beam
≤ 5MeV
Ionising Radiation
X-ray
≤ 10 MeV
The food is carried through the radiation beam on a conveyer
Key Facts

Irradiation with the approved radiation sources
cannot make food radioactive

The energy absorbed in the food brings about
changes in the chemicals present in the food or its
contaminants
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The “amount” of radiation absorbed by the food is
the DOSE. Dose is measured in Gray (Gy).
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1 Gy = 1 Joule absorbed per kg food. 1 kGy = 1000 Gy
The Chemical Changes
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All food processing technologies cause some
change to the food.
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At low doses changes in hormone levels can occur
(effects on ripening and maturation)
At higher doses, changes to the DNA of living cells
can cause sterility or death
Like all processing technologies, some changes to
food ‘structure’ and its constituents can occur
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The trick is to ensure benefits occur at lower doses than
detrimental effects
Applications
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Improving food safety
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Food free of disease-causing pathogens
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Reducing food wastage
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E Coli 0157:H7: campylobacter, salmonella, listeria
Control maturation, inhibit sprouting, reduce
storage decay
Assisting international trade
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Phytosanitary use, insect disinfestation for
quarantine purposes
Food Irradiation is 
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Versatile (more applications than other processes)
Well-researched
Suitable for most foods; benefits occur at lower
doses than loss of quality
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Foods that auto-oxidize easily and which tend to go
rancid naturally are usually unsuitable ( avocados, oily
fish, many dairy products)
BUT It is used to a very limited extent – why?
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Between 500,000 to 1,000,000 tonnes irradiated per year
A Barrier to Food Irradiation 
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Conventional wisdom says that consumers are
scared of a technology associated with radiation
The retail trade is very cautious because they fear
consumer reaction
Food producers are very cautious because they
can’t see a market
No-one wants to be involved in an “information”
campaign
But is conventional wisdom right ????
Irradiation – A Phytosanitary
Treatment for International Trade
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The irradiation dose used is usually 150 – 400 Gy
Such doses have a minimal effect on the quality of
most fruits and vegetables
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Given proper treatment from harvest to retail, product
quality is usually higher than competing treatments
The end point for quarantine control is loss of
ability to emerge from larval stage or adults
incapable of reproduction; the insects are sterile
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Doses that guarantee to kill ALL insects quickly are too
high for most fruits to withstand without loss of quality
Irradiation Advantages
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It is a broad spectrum treatment (all insects,
all host produce)
It is free of toxic chemical residues
It is a cold treatment (no heating means fruit
can be more mature at harvest and often
results in better fruit quality and shelf-life)
It is penetrating (treatment in the final
package; fruit size and shape are
unimportant)
Irradiation Advantages
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It is rapid (approximately an hour)
Treated produce can be released into trade
immediately
It is simple, depending only on conveyer
speed and source power to set the dose. It is
insensitive to temperature, humidity,
pressure, etc
It is cost competitive
Regulatory issues
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Before irradiated fruits and vegetables can
be imported, two regulatory tests must be
met
The national health authority must approve its
use as a safe process for food
 Biosecurity authorities in the exporting and
importing countries must agree an irradiation
protocol that will manage the pests of concern
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Is Irradiated Food Safe to Eat?
YES
 The evidence is overwhelmingly that irradiated
food is toxicologically safe, and presents no special
nutritional or microbiological problems
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Codex Alimentarius issued a General Standard for
Irradiated Food (1983, revised 2003).
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Any food irradiated up to an overall average dose of 10
kGy is safe and wholesome.
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Note phytosanitary use has a maximum dose of 1 kGy
An Agreed Protocol for Irradiation as
a Phytosanitary Treatment?
YES
 The International Plant Protection Convention
(IPPC) has issued ISPM 18, Guidelines for the Use
of Irradiation as a Phytosanitary Treatment (2003)
 ISPM 28 (2009) has recommended that 150 Gy be
regarded as the generic dose to ensure sterility of
all Tephritid fruit fly on all hosts
 The USDAS-APHIS accepts 400 Gy as a generic
dose to deal with all insect species (except
Lepidoptera) on all hosts
International Approvals - Health
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23 countries have approved irradiation up to
1 kGy for all fruit and vegetables
12 countries have approved irradiation up to
1 kGy for specified fruits and vegetables
28 countries have approved irradiation as a
disinfestation treatment
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7 other approvals are for delay of ripening or
maturation control
Approvals in Australia and New
Zealand
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Food Standards Australia New Zealand is a joint
standard setting body
It approved Standard 1.5.3 for the Irradiation of
Food in 1999
Under the Standard applications must be made for
specified foods and uses
A maximum dose of 1 kGy may be used for insect
disinfestation of 9 fruits
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Breadfruit, carambola, custard apple, longan, litchi,
mango, mangosteen, papaya, rambutan
Trade in Irradiated Fruits
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In 2004, New Zealand became the first country to
accept and import irradiated fruit from another
country (Australian mango)
Before shipments proceeded Biosecurity NZ 
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checked that mango irradiation was permitted under
FSANZ Standard 1.5.3
completed a thorough pest risk assessment and a study
of management options for the pest of concern, with
irradiation as the primary option
issued an Import Health Standard under MAFBNZ
standard 152.02 (Biosecurity Act 1993)
Trade in Irradiated Fruits
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The USA established trade between Hawaii and
the continental USA in papaya from 1995 and
later in sweet potato and a few other fruits.
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Today about 4,500 tons of irradiated fruit is traded
between Hawaii and the mainland
Irradiated fruits from Florida are also sent to other US
States
More recently (2007 onwards) the USA has
imported several types of irradiated fruit from
four developing countries
Irradiated Imports into NZ (tonnes)
2004-06
2007
2008
2009
2010
Mango
256
228
261
585
1095
Papaya
0
13
1
0
0
Litchi
0
10
21
57
110
Total
256
251
283
642
1205
Irradiated Imports into US (tons)
Country
India
Thailand
Vietnam
Mexico
Fruit
2008
Mango
275
Longan (mainly)
1700
Dragonfruit
0
Guava
257
Grapefruit
0
Mango
0
Sweet Lime
0
Manzano Pepper
0
Total 2232
2009
130
1890
100
3521
67
0
0
0
5708
2010
195
1800
850
9121
101
239
600
257
13,163
The Live Insect Issue
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Irradiation below 1 kGy guarantees insect sterility,
not mortality.
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Not all are killed and a live insect is occasionally
found in shipments by the receiving country
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For other methods, a live insect signals treatment
failure and a requirement for rejection or further
treatment of the shipment (usually MeBr)
The Live Insect Issue
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Occasional live insects have been found in
irradiated shipments to NZ
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These are managed through a new procedure
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The insect is identified
If the dose on the phytosanitary certificate is sufficient
for sterilisation of the identified insect (refer to a MAF
Biosecurity table or the import health standard) then the
shipment is cleared for import
The Consumer Issue
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When irradiated mangoes were first introduced
into NZ, there was a flurry of protest in cyberspace
from ‘anti-irradiation’ activists and supporters of
minimal processing of food
This resulted in minor negative publicity in
mainstream media
The negative publicity soon evaporated
Irradiated Australian mangoes are now sold, at a
premium, in major supermarkets with volumes
increasing
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This is the typical experience wherever
irradiated food has been introduced
Consumers will purchase and re-purchase
high quality irradiated foods
Labeling
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Some consumers (20%?) will never purchase
irradiated foods for a variety of reasons
FSANZ Standard 1.5.3 requires that
irradiated foods be labeled in order to ensure
these consumers retain their right-to-choose
Labeling of irradiated foods has disarmed
much of the criticism of the process.
The Future
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The USA has been actively encouraging
developing countries to send irradiated fruits to the
USA
The rapid expansion in imports to the USA seems
likely to continue
As the NZ and US experience is made known, and
the familiarity is gained with how to deal with the
occasional live insect, trade between other
countries is likely to begin
The Future in New Zealand
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Processes are in place that would allow the
expansion of imports of irradiated fruits
from countries with a strong national plant
protection organisation
The recent experience has been positive for
both quarantine officials and retailers
Trade is likely to grow, but probably quite
slowly, fruit-by-fruit and country–by-country
The Future in Australia
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An Interstate Certification Assurance
protocol for irradiation as a phytosanitary
measure has been approved (ICA-55)
This would allow irradiation to be used as a
replacement for insecticide treatments such
as dimethoate and fenthion
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Methyl bromide should not be seen as a
sustainable or safe long term option
The Future in Australia
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It is probable that irradiation will be trialed for
fruit trade between states in the relatively near
future
The stage appears set for an increase in exports
using irradiation, initially to NZ but later to other
countries (the US is an obvious candidate)
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This could include strawberries irradiated to higher
doses to achieve substantial increases in shelf-life
Australia may also expect other countries to
request access for their irradiated fresh produce
Conclusions (1)
1. Irradiation is a practical, efficient and
effective phytosanitary treatment of fresh
fruit and vegetables
2. 28 countries have approved irradiation of
fresh fruits and vegetables for
disinfestation purposes
3. International trade to New Zealand in
irradiated fruit treated to meet quarantine
requirements began in 2004
Conclusions (2)
4. Presently over 13,000 tonnes of irradiated fruits
are imported annually into New Zealand and the
USA.
5. The trade has grown fairly quickly and appears
set to continue to expand
6. Experience has shown that consumer resistance
is overestimated and the issue of live insects in
occasional shipments can be managed
7. Irradiation offers the prospect of decreasing
reliance on toxic insecticide and fumigation
treatments
Thank You
For a copy of the presentation or
further information contact
[email protected]