Irradiation of Animal Feeds - Sterigenics

Food Safety
Irradiation of Animal Feeds
Irradiation is an effective microbial disinfection
process for animal feeds. It is currently used
in the United States for feeds for research and
lab animals, and under FDA special permission
letters, for dog chews to control microorganisms
such as Salmonella. The irradiation of poultry
feed for control of Salmonella is also approved by
FDA (21 CFR § 579.40).
Microbiological contamination of feed and
feed ingredients is an animal health, human
health and a food trade issue. Feeds are
an important vector of microbial contaminants
that can impair both animal health and various
performance parameters. When the feed is
destined for domestic pets, the presence
of bacteria could affect the health of the pet’s
human family. There have been several cases
of children contracting Salmonellosis from
handling dog chew treats. Additionally, the
presence of microbiological contaminants can
prevent the trade in feeds.
Currently, 21 CFR § 579.22 provides for
the irradiation of lab animal chow to 50 kGy,
and Part 579.40 provides for poultry feed to
25 kGy. There is no prescribed minimum dose
for lab animal chow, but a minimum dose of
2.0 kGy has been prescribed for poultry feed
in the regulation.
Sterigenics Food Safety has prepared a petition
to the US FDA–Center for Veterinary Medicine
to approve the irradiation of animal feed to a
maximum dose of 50 kGy.
Irradiated Animal Feed Products
In the United States, Sterigenics has been
asked to assist feed companies and their
customers to control microbial contamination
of animal feeds. For example, in the past five
years Sterigenics has been asked to irradiate:
animal protein feed components
(from blood, eggs, organ meats and
rendered products)
plant protein feed components
such as Brewer’s Yeast
dog food (dry and semi-moist), including
dog chews (such as pigs ears, bullwinkles,
rawhide and similar items)
aquaculture feeds and pet fish food
various foods for zoo and aquarium
animals and creatures
high value starter diets for young animals
(calf, swine)
feeds for lab animals
birdseed for wild and pet birds
In the case of feeds destined for research
animals, the industry has been able to work
with manufacturers to produce sufficiently
decontaminated, or even sterile feeds.
In other countries, members of the contract
irradiation industry have been asked to irradiate:
baled forage crops (such as Timothy hay)
for race horses (currently commercially
irradiated for trade between Australia
and New Zealand)
second quality grains for animal feeds
birdseed (sometimes commercially
irradiated in Canada as condition of entry)
components of animal medicines (currently
commercially irradiated in Thailand).
In addition, we believe there are other animal
feeds that could benefit from irradiation
treatment that have not yet been identified.
How Does Irradiation Work
Irradiation is a physical process using approved
sources of radiation (generating gamma energy,
accelerated electrons or X-rays) to disinfect
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Irradiation of Animal Feeds
feeds. In this process, sufficient energy is
absorbed by the feed to kill molds, bacteria,
yeasts, insect pests and weed seeds.
Irradiation is intended to disinfect feeds
of microbial contamination, but since insect
pests are generally more sensitive to radiation
than bacteria (depending on life stage and
other factors), they would usually be killed
at any dose commercially used to control
microbial contamination.
Microbiological Effects of Irradiation
on Feed and Feed Components
As a result of decades of research on the effects
of irradiation, Sterigenics has a very complete
understanding of the effect of irradiation on
microbial contaminants. Most important is the
general agreement in the microbiology research
of the effectiveness of irradiation as a means to
control microbial contamination in a wide
variety of products.
If we look at the detail of the research results
on the effect of irradiating dry feeds, however,
we do not, see an overwhelmingly consistent
picture. Feeds and their ingredients vary
considerably in formulation, moisture content,
physical properties and bioburden.
Reported D 10 values for many bacterial
contaminants vary from 0.4 kGy to 2.2 kGy
depending on the organism(s), type of feed and
test conditions such as temperature. Where
log reductions were reported, a dose range of
3.75-7.5 kGy was suggested to result in a 5-8
log reduction in a number of bacteria
(including Salmonella), and fungi. One study
noted significantly lower doses were required
for pelletized feeds versus non-pelletized feeds.
Where the researchers noted effective
sanitization doses, 5-8 kGy was considered to
control coliforms; 8-15 kGy was advised to
control all enterobacteria; 6.5 kGy eliminated
Staphlococcus; and 2-4 kGy controlled Aspergillis.
For sterility of lab animal chow, 25 kGy was
recommended; that dose was also recommended
in other experiments to decontaminate feeds
that were probably quite contaminated.
Our experience with spices, herbs, botanicals
and other dry ingredients (which have a similar
bioburden to many feeds, and also being
relatively dry, have a similar dose response),
tells us that, assuming initial bioburden levels
are not unusually high, a minimum dose of
about 7 kGy is usually sufficient to achieve
a level of decontamination that is acceptable to
spice processors and their customers. However,
we note that some spices, such as black pepper,
known to have higher levels of contamination,
often require a minimum dose of up to 20 kGy.
Effects of Irradiation on Nutrient
Value of Animal Feed
The effect of irradiation on the nutrient value
of the feed should be assessed as part of the dose
determination before commercial processing
begins. It is the manufacturers’ responsibility
to ensure the nutrient value of the feed is not
significantly compromised by the irradiation
processing. Manufacturers of animal feeds
should take note of radiation effects on key
nutrients for the species being fed and
supplement as necessary.
Generally, the need to control microbiological
contamination outranks the nutritional effects
issue in decisions (since the nutrient content
of animal feeds can be easily manipulated), but
there are a few important issues that temper
dose selection considerations.
First, if the feed is destined for young animals
or known-to-be-sensitive species (for example,
starter feeds, aquaculture feeds for young fish
or single diets for valuable zoo animals), where
significant nutritional losses could result in
problems with the fed species, we strongly
advise the customer to test the nutritional value,
focusing on nutrients that are both radiation
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Irradiation of Animal Feeds
sensitive and key nutrients for that species.
We can work with the customer to advise them
about the nutrients that are known to be
radiation sensitive, but we rely on the customer
to know the key nutrients for the fed species.
Not all feed products are significant sources
of nutrients (rawhide treats as an example),
so nutrient assessment is not always a necessity.
We also note that while organoleptic concerns
are very important aspects in dose selection
for human foods, this seems to be less of
a consideration for the irradiation of animal
feeds. We would expect the manufacturer
to ensure irradiation does not affect acceptance
by the fed animal.
Protein and Amino Acids
Crude protein levels and total nitrogen contents
have not been found to be affected by irradiation
treatment in the range of animal feeds tested
at dose levels even as high as 150 kGy.
A number of authors studying a variety of feeds,
including fishmeals, meat rendering products
and cereal-based diets, reported that irradiation
with doses as high as 100 kGy did not affect
biological value. Small losses in protein value
were found in some grain products but not
fishmeal or spray-dried blood protein. Net
protein utilization was generally not affected
by irradiation treatment. Similarly, protein
digestibility and nitrogen digestibility were, in
most cases, unaffected by irradiation treatment.
Total amino acid levels in animal feed rations
are generally not affected by irradiation doses
as high as 100 kGy. However, it is more critical
to look at the effects of irradiation on individual
amino acid concentrations to get a true measure
of irradiation-induced changes. It is well known,
for example, that different livestock and poultry
species have different requirements for
individual amino acids.
In some studies, no changes in amino acid
composition were reported even after irradiation
doses up to 100 kGy. Additional information
is available from Sterigenics on specific amino
acid effects for the reader who wants more
information on this aspect.
Other studies have reported changes, however,
and these differences may be related to variances
in diet composition and varying analytical
techniques. Many studies do not differentiate
between total and available amount of an amino
acid, making comparison of results between
studies more difficult.
Vitamins
The effects of irradiation on vitamins are
dependent on the formulation of the diet, the
dose of irradiation and the particular vitamin.
Conning (1983) suggested that at doses above
25 kGy, vitamin supplementation would be
required for commercial and laboratory animals
to thrive normally on irradiated feeds.
Vitamin A
Vitamin A has been found to decrease in most
animal feeds (including fish meal, pelleted rabbit
feed and various rodent, chick, cat and pig diets)
after irradiation with doses as low as 20 kGy.
Effects appear to be diet dependent. Reductions
of as much as 70% have been reported in
cereal-based rat rations after doses of 45 kGy.
Vacuum packaging may provide some protection
against radiation effects.
Beta carotene (precursor of vitamin A)
The effects of radiation on beta carotene
levels in various animal feeds are not consistent.
A dose of 25 kGy reportedly had no effect
on levels in lab mice diets. In contrast, doses
of 20-50 kGy caused reductions ranging from
13% to 100% in rabbit and chick diets.
Vitamin B
Several forms of the B vitamins have been
studied including B1 (thiamine), B2 (riboflavin),
B5 (niacin), B6 (pyroxidine), B10 (biotin) and
B12 (cyanocobalamin).
Thiamine
The sensitivity of thiamine to radiation
treatment varies with the type of feed. In lab
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Irradiation of Animal Feeds
mice, chick and guinea pig diets, it has been
reported that doses of up to 25-30 kGy caused
no changes in thiamine content. However,
doses as low as3-6 kGy have caused reductions
in fish protein.
Riboflavin
Riboflavin is reportedly one of the most
radiation resistant of the vitamins. No changes
in riboflavin levels were observed in lab mice
diets after a dose of 25 kGy.
Niacin
Niacin is only slightly less resistant to irradiation
than is riboflavin. No reductions in niacin
content were observed in lab mice or rat diets
irradiated with up to 40 kGy, or in fish protein
treated with doses up to 45 kGy.
Pyroxidine
Pyroxidine has a radiation sensitivity similar
to thiamine. While no effects were observed
in lab mice, chick and guinea pig diets treated
with 25-30 kGy, reductions were observed in
fish protein irradiated with doses as low as 3-6
kGy. Doses of 50-70 kGy led to reductions
of 15-21% in a range of feed types. The presence
of antioxidants at particular concentrations may
increase the level of pyroxidine destruction.
Biotin
Biotin generally has a high level of radiation
resistance. No effects were observed in lab mice
diets after a dose of 25 kGy, although a
reduction was observed in wheat grain after
treatment with 2 kGy.
Cyanocobalamin
Radiation generally causes only minimal losses
of Vitamin B12. No change was observed in
lab mice diets treated with 25 kGy and only
a 7% loss was reported in various pig feeds
treated with 50 kGy.
Vitamin C
A dose of 25 kGy led to a loss of 21% of
vitamin C in pelleted rabbit feed. A study on
the effects of irradiation on Vitamin C must
also measure dehydroascorbic acid. Radiation
treatment induces oxidation of ascorbic acid
to dehydroascorbic acid, a form that is equally
biologically active.
Vitamin D
Vitamin D is generally more radiation resistant
than vitamins A or E, particularly in high fat
substrates. However, a dose of 20 kGy was
found to cause a reduction of vitamin D content
in fishmeal.
Vitamin E
Vitamin E is the most sensitive of the vitamins
to radiation treatment. Losses were reported
in fishmeal, rice bran, pelleted rabbit diets
and pig feed after treatments ranging from
20 kGy (fish meal) to 50 kGy (pig feed) and
were as high as 60% (pig feed). However, other
researchers reported that irradiation as high
as 40 kGy did not affect vitamin E levels
in rat and mice feeds.
Results appear to be somewhat dependent
on the type of vitamin E molecule present.
Alphatocopherol, for instance, is less radiation
sensitive than some other forms and has been
recommended as a source of vitamin E
enrichment for irradiated feeds. Results are diet
dependent, but doses as high as 50 kGy have
reportedly not caused alphatocopherol losses
in pig, guinea pig or cat diets and only slight
reductions in fish protein and chick diets.
Alphatocotrienol has been suggested as the
most sensitive of the E vitamers to radiation
treatment, with 89% being destroyed following
a dose of 15 kGy in rice bran.
Vitamin K and folic acid
A dose of 40 kGy led to a decrease of 76% in
the level of vitamin K in rat and mouse feed.
Doses of 20-30 kGy did not affect folic acid
levels in chick or guinea pig cereal-based diets,
but did cause a reduction in cat diets. A loss
of 17% was reported in various pig diets after
treatment with 50 kGy.
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Irradiation of Animal Feeds
Pantothenic acid
Pantothenic acid has a radiation resistance level
similar to that of the most radiation resistant
vitamins. However, slight losses have been
observed in wheat at levels as low as 0.2 kGy.
No effects were observed after treatment of lab
mice diets with a dose of 25 kGy. Similarly,
a dose of 50 kGy led to only a 2% loss in sow,
creep and hog feeds.
Lipids
The effects of irradiation on dietary lipids are
dependent on lipid concentration, fatty acid
composition, packaging, formulation of the diet
and irradiation dose. Changes in fatty acid
profiles and free fatty acid levels have been
reported depending on the feed and
irradiation dose.
Peroxide value, a measure of the oxidative
rancidity of the fat, has generally been shown
to increase after irradiation treatment. In
fishmeal irradiated with a dose of 14 kGy,
peroxide levels almost doubled. However, in the
same study, irradiation had no effect on levels
in ready-mixed pig feeds or at a dose of 7 kGy.
Increased levels were observed, however, in
commercial cat diets irradiated with 25 kGy,
poultry diets irradiated with 30-60 kGy and
wheat irradiated with 5-500 kGy. Neither
oxidized fatty acids or unsaturated fatty acid
levels were affected by doses of 7-14 kGy
applied to fishmeal or ready-mixed pig feed.
A dose of 15 kGy resulted in increased levels
of free fatty acids and a reduction in
phospholipids in rice bran.
Negative effects on organoleptic properties
associated with dietary lipids have been reported
after irradiation of wheat.
Fiber
Irradiation at high doses has been suggested
as a means to break down the fiber contained in
animal feeds, making them more digestible.
Results will depend on the actual dosage and
the composition of the feed being studied.
Irradiation has been found to reduce crude fiber
content in various types of feeds. Feed blocks
irradiated with doses of 100 kGy also exhibited
reductions in hemicellulose and neutraldetergent
fiber concentrations. Organic matter
digestibility and in vitro digestible energy both
increased. Gross energy, cellulose, acid-detergent
fiber and acid-detergent lignin were not affected
by the irradiation treatment. Only slight
changes were observed in acid detergent fiber
and lignin in alfalfa hay, corn cobs, wheat bran
and straw after irradiation treatment.
Digestibility of crude fiber in pellets irradiated
with a dose of 50 kGy decreased.
While radiation treatment may lead to
a reduction in feed particle size and enhance
digestibility of the feed, there may also be
a reduction in mean retention time in the
digestive tract of the animals so that less
nutrients are absorbed.
Anti-nutritional Factors
Some animal feeds naturally contain chemical
compounds that are detrimental to animal
growth and development. In some instances,
these factors can be fully or partially eliminated
by irradiation treatment. Safflower oilcake, for
example, contains the proteinase inhibitors
trypsin and chymotrypsin. A dose of less than
1 kGy was sufficient to inactivate trypsin while
chymotrypsin was still active after a dose of
10 kGy.
Effects of Irradiated Feeds
on Animal Performance
Several studies have been conducted looking at
the effects of various types of irradiated feed on
the performance of livestock, poultry and lab
animals.
Poultry
An analysis of several irradiated poultry feed
studies indicates that doses of irradiation up
to approximately 25 kGy have no effect on
growth parameters such as weight gain, feed
utilization, consumption or efficiency, or egg
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Irradiation of Animal Feeds
number, weight or fertility. However, above
25 kGy, some detrimental effects have been
observed, in part because of degradation of
Vitamins A and D.
Pigs
While poultry generally are fed a cereal-based
diet, the rations fed to pigs are more varied,
ranging from fishmeal to cereals to meat
rendering byproducts. Doses up to 50 kGy,
however, have generally not been found
to affect growth rate, feed intake or efficiency,
weight gain, reproductive characteristics
or piglet growth.
Sheep
Feeding merino sheep wheat and rice straw
that had been irradiated with doses ranging
from 250 kGy to 750 kGy resulted in reductions
in voluntary feed intake, digestibility, nitrogen
balance and rumenal volatile fatty acid
production. Feed particle size was reduced by
the radiation treatment but this advantage was
offset by a reduction in mean retention time
of the feed in the digestive tract of the animals.
Rats and mice
Weight gain and reproductive characteristics
of mice and rats were reportedly not affected by
consumption of irradiated feed at 25 or 45 kGy.
Effects on feed intake are less consistent. In
contrast, heat treatment of diets has been found
to reduce growth rates. In other experiments,
no effects of feeding fish meal that had been
treated with a dose of 8 kGy on organ weight,
hematological, histological, enzymological
or fertility characteristics were found.
References
1. Adler JH, Eisenberg E, Lapidot M, et al:
Treatment of animal feeds with ionizing
radiation: 2. Effects of gamma radicidation
on the biological value of poultry feed.
Food Preservation by Irradiation. Vol.2.
International Symposium on Food Preservation
by Irradiation; Wageningen (Netherlands); 21-25
Nov 1977. International Atomic Energy Agency,
Vienna (Austria): 243-54, 1978.
2. Al Masri MR: Nutritive value of some feed
blocks, as influenced by gamma irradiation.
Agribiological Research 48:171-78, 1995.
3. Badshah, Amal, Aurangzeb, Sattar A,
Nizakat Bibi: Effect of irradiation and other
processing methods on in-vitro digestibility
of rapeseed protein. J Sci Food Agric
61:273-75, 1993.
4. Bhatty RS, Macgregor AW: Gamma
irradiation of hulless barley: Effect on grain
composition, beta-glucans and starch.
Cereal Chem 65:463-70, 1988.
5. Coates ME, Ford JE, Gregory ME, et al:
Effects of gamma irradiation on the vitamin
content of diets for laboratory animals.
Lab Anim 3:39-49, 1969.
6. Conning DM: Evaluation of the irradiation
of animal feedstuffs. In Recent Advances in Food
Irradiation. Elsevier Biomedical Press.
247-83, 1983.
7. Cox C, Nikolaiczuk N, Idziak, ES: Poultry
feed radicidation: 2. Long and short term
poultry feeding trials with irradiated poultry
feeds. Poultry Sci 53:619-24, 1974.
8. Eggum BO: Effect of radiation treatment
on protein quality and vitamin content of animal
feeds. Decontamination of Animal Feeds by
Irradiation. Advisory Group Meeting on Radiation
Treatment of Animal Feeds; Sofia (Bulgaria);
17-21 Oct 1977. International Atomic Energy
Agency, Vienna (Austria): 55-67, 1979.
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Irradiation of Animal Feeds
9. El-Moneim A, Afify RM, Shousha MA:
Effect of low-dose irradiation on soybean
protein solubility, trypsin inhibitor activity, and
protein patterns separated by polyacrylamide
gel electrophoresis. J Agric Food Chem
36:810-813, 1988.
10. El Saadany RMA, El Saadany FM,
Foda YH: Degradation of corn starch under the
influence of gamma irradiation. Starch
28:208-11, 1976.
11. Farag MDEH: The nutritive value for chicks
of fullfat soybeans irradiated at up to 60 kGy.
Anim Feed Sci Technol 73:319-28, 1998.
12. Ferrando R, Pantaleon J, Fromageot D:
Comparative study of classical sterilization
and radappertization on a feed for the rat.
Ann Nutr Aliment. 22:25-27, 1968.
13. Food and Drug Administration: Irradiation
in the Production, Processing, and Handling
of Food. Final Rule. Federal Register 51 FR
13376-13399, April 18, 1986.
14. Ford DJ: The effect of methods of
sterilization on the nutritive value of protein
in a commercial rat diet. Brit J Nutr 35:267-76,
1976.
15. Observations on the influence of irradiation
on fat and vitamin A in dry laboratory cat diets.
Decontamination of Animal Feeds by Irradiation.
Advisory Group Meeting on Radiation Treatment
of Animal Feeds; Sofia (Bulgaria); 17-21 Oct
1977. International Atomic Energy Agency, Vienna
(Austria): 77-81, 1976.
16. Horvatic M, Gruner M: Effect of gamma
irradiation on methionine and tryptophan
content in soya protein products. Nahrung 37:
147-52, 1993.
17. Ito H, Iizuka H: Present status of radiation
treatment of animal feeds in Japan.
Decontamination of Animal Feeds by Irradiation.
Advisory Group Meeting on Radiation Treatment
of Animal Feeds; Sofia (Bulgaria); 17-21 Oct
1977. International Atomic Energy Agency, Vienna
(Austria): 15-31, 1979.
18. Joseph A, Dikshit M: Effect of irradiation
on the proteinase inhibitor activity and
digestibility (in vitro) of safflower oilcake.
Journal of the American Oil Chemists’ Society
70:935-37, 1993.
19. Kennedy TS: Studies on the nutritional
value of foods treated with gamma radiation.
I. Effects on some B-complex vitamins in egg
and wheat. J Sci Food Agric 16:433-37, 1965a.
20. Kennedy TS: Studies on the nutritional
value of foods treated with gamma radiation.
I. Effects on some B-complex vitamins in egg
and wheat. J Sci Food Agric 16:81-84, 1965b.
21. Kume T, Takehisa M: Effect of gamma–
irradiation on lysinoalanine in various
feedstuffs and model systems. J Agric Food Chem
32:656-58, 1984.
22. Leeson S, Marcotte M: Irradiation of
poultry feed. 2. Effect on nutrient composition.
World’s Poultry Science Journal 49:120-131, 1993.
23. Ley FJ: Radiation processing of laboratory
animal diet. Radiat Phys Chem 14:677-82, 1979.
24. Matin MA, Amin MR, Rahman S, et al:
Nutritional value of poultry feed
decontaminated by irradiation. Indian Vet J
62:251-54, 1985.
25. McManus WR, Manta L, McFarlane JD,
et al: The effect of diet supplements and gamma
irradiation on dissimilation of low-quality
roughages by ruminants: 3. Effects of feeding
gamma-irradiated base diets of wheaten straw
and rice straw to sheep. J Agric Sci 79:55-66,
1972.
26. Metta VC, Johnson BC: Biological value
of gamma irradiated corn protein and wheat
gluten. Agric Food Chem. 7:131-33, 1959.
27. Mossel DAA: Perspectives for the use
of ionizing radiation in the decontamination
(Salmonella radicidation) of some frozen
proteinaceous foods and dry mixed feed
ingredients. In Food Irradiation. Proceedings
of an FAO/IAEA Symposium. Karlsruhe,
Germany. June 6-10, 1986: 365-80, 1986.
28. Nadudvari I: Experience of radiation
treatment of laboratory and farm animal feeds
in Hungary. Decontamination of Animal Feeds by
Irradiation. Advisory Group Meeting on Radiation
Treatment of Animal Feeds; Sofia (Bulgaria);
17-21 Oct 1977. International Atomic Energy
Agency, Vienna (Austria): 33-41, 1979.
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Irradiation of Animal Feeds
29. Roushdi M., Fahmi AA, Sarhan M: Effect
of gamma rays on corn grains. III. Effect of
post-irradiation storage on some technological
properties of corn grains and fatty acids.
Starch/Staerke 33: 163-65, 1981b.
30. Roushdi M, Harras A, El Meligi A, et al:
Effect of high doses of gamma rays on corn
grains. I. Influence on the chemical composition
of whole grains and the technological process
of starch and by-product isolation. Cereal Chem.
58: 110-112, 1981a.
31. Sandev S, Karaivanov I: The composition
and digestibility of irradiated roughage.
Decontamination of Animal Feeds by Irradiation.
International Atomic Energy Agency, Vienna
(Austria)Advisory Group Meeting on Radiation
Treatment of Animal Feeds; Sofia (Bulgaria);
17-21 Oct 1977: 83-87, 1979.
32. Shin TS, Godber JS: Changes of
endogenous antioxidants and fatty acid
composition in irradiated rice bran during
storage. J Agric Food Chem 44:567-73, 1996.
33. Tipples KH, Norris FW: Some effects
of high levels of gamma irradiation on the lipids
of wheat. Cereal Chem. 42:437-51, 1965.
34. Vijayalaxmi: Cytogenetic studies in monkeys
fed irradiated wheat. Toxicology 9:181-84, 1978.
35. Wang GJ, Marquardt RR, Guenter W, et al:
Effects of enzyme supplementation and
irradiation of rice bran on the performance
of growing Leghorn and broiler chickens.
Anim Feed Sci Technol 66:47-61, 1997.
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