]]]]]]]]]]]]]]]]       FOOD IRRADIATION          [[[[[[[[[[[[[[[
                   Information Letter No. 746
       Health and Welfare Canada, Health Protection Branch
                           4 June 1988

            [Kindly uploaded by Freeman 10602PANC]

[The  present  paper  excerpts   those  substantial  portions  of
Information Letter No. 746 which  deal with the health aspects of
food irradiation.   Material dealing  with statutory, regulatory,
definitional and other considerations has been omitted.
   The material presented is consistent with the proposition that
         ... irradiation of  any food commodity  up to an overall
         average dose of 10 kGy presents no toxicological hazard;
         hence toxicological  testing of  foods so  treated is no
         longer required.
                         World Health Organization,
                         Wholesomeness of Irradiated Foods (1981)
though the  Canadian regulatory  authorities prefer  to ``examine
each submission  [for permission to  irradiate a  foodstuff] on a
case-by-case  basis to  determine if  additional or  new toxicity
testing is required''.
   I am most grateful to Mr  Jaroslav Franta of the Committee for
Accuracy in Nuclear Issues in  the Media, 2252 Kaufman, Montreal,
Quebec,  Canada  H4K  2G3, for  providing  me  with a copy of the
original document. -- Oleg Panczenko]

                      [Pages 1-18 omitted.]

[Page 19]

Toxicology and Safety of Irradiated Foods

[Apology for the technical level of this section omitted.]

(18)  ...  [A]  respondent expressed  concern  that  some  of the
studies on irradiation [of food] had been conducted by Industrial
Bio-Test  Laboratories  (IBT),  an  American  firm  implicated in
improperly conducting many of  the safety studies performed under
contract to  its clients.   Finally, a  respondent contended that
only 1%  (5) of  the 413 studies  available to  the United States
Food  and Drug  Administration  (U.S.F.D.A.) appeared  to support
[Paragraph omitted.]
[Page 20]
   With regard to a limited number of studies on irradiated foods
conducted by IBT,  these have been  discounted in connection with
the recent review on the safety of irradiated foods undertaken by
Branch toxicologists,  insofar as  there were  available numerous
replacement  short  and  long-term  studies  performed  by  other
reputable  institutions  investigating   the  toxicity  of  these
particular foods and others.
   With regard to the numbers of studies that support safety, the
U.S.F.D.A.  (1986)  indicted  in   its  recent  Federal  Register
document that:
     "Only 5 of  the 441 studies reviewed  ... were considered by
     agency reviewers to be properly conducted, fully adequate by
     1980 toxicological standards, and able to stand alone in the
     support of safety."
   The operative  phrase is the  last one.   The Federal Register
article goes on to say:
     "Although most of  the studies were  generally inadequate by
     present day standards  and could not  stand alone to support
     safety,  many  contained individual  components  which, when
     examined either  in isolation  or collectively,  allowed the
     conclusion that consumption of foods treated with low levels
     of irradiation did not appear to cause adverse toxicological
   It is important to recognize that these studies were conducted
for a myriad of reasons via many different protocols designed for
many  different  purposes.   A  substantial  percentage  of these
studies were conducted  in an era  prior to the "standardization"
of several types of toxicity testing protocols.  Although some of
these studies  may well be  classified as inadequate  in light of
present standards, the  fact remains that  the essential findings
and interpretations are valid and useful.
[Page 21]
   It  should  be   noted  that  other   agencies,  such  as  the
U.S.F.D.A., and expert scientific and toxicological panels around
the world such  as the Joint  Food and Agricultural Organization/
International  Atomic  Energy  Agency/World  Health  Organization
(FAO/IAEA/WHO) Expert  Committee on Food  Irradiation (1981), the
United Kingdom Advisory  Committee on Irradiated  and Novel Foods
(1986), and  the United  States Council  for Agricultural Science
and  Technology   (CAST;  1986)   have  reviewed   the  extensive
toxicological data base  and have attested  to the overall safety
of irradiated foods at doses of practical commercial importance.
[Paragraph omitted.]
(19) One respondent indicated  that two relatively recent Russian
studies demonstrated damage to the kidneys and testes of rats fed
irradiated food.
   In the  first paper by  Levina and Ivanov  (1978), the authors
reported     an      increase     of     membranous-proliferative
glomerulonephritis  in   kidneys  of   rats  fed   an  irradiated
laboratory diet  for 20  months.  The  study (original scientific
paper  translated  into  English) has  been  evaluated  by Health
Protection Branch toxicologists.  No  quantitative data [page 22]
were presented to asses the potential toxic effects of irradiated
diet on kidneys.  Neither were  individual animal or summary data
   The results did not define the frequency of kidney lesions for
any of the experimental groups.  Historical control data were not
provided and  the strain  of rats employed  in this  work was not
defined.  It was concluded that the toxicological significance of
these findings cannot be evaluated from the available data.
   In the second  paper by Ivanov and  Levina (1981), the authors
reported an  increase of  degenerative changes  (enlarged testes;
differences  in  size  and  weight  of  right  and  left  testes;
degeneration  of  seminiferous tubules;  proliferation  of Leydig
cells; signs  of aspermatogenesis;  coagulation necrosis)  in the
testes of  21-month-old rats  fed gamma-irradiated  (0.25-56 kGy)
laboratory diet for a period of 20 months. An English translation
of the report was evaluated  by Branch toxicologists.  The report
did not specify the  strain of rats used,  the composition of the
diet,  animal housing  conditions and  the exact  radiation doses
used  (only range  given).   The histological  findings  were not
adequately  defined or  documented.  Individual  lesions observed
were not defined quantitatively.  It  was thus concluded that the
results   were   inadequate   to   determine   the  toxicological
significance  of  the  reported findings.   It  should  be noted,
however,  that degenerative  and  atropic testicular  lesions are
relatively common  in older rats  (Goodman et  al., 1979; Cotchin
and Roe, 1967).
(20) The same respondent cited  a study (Bhaskaram and Sadasivan,
1975)   in    which   malnourished   children    in   India   fed
freshly-irradiated wheat (fed within 2  to 3 weeks of irradiation
at a dose of 0.75 kGy) showed an increase in abnormal white blood
cells   (polyploidy).   Also   [page  23]   cited  was   a  study
(Vijayalaxmi, 1978) in  which polyploidy was  observed in monkeys
fed wheat irradiated at 0.75 kGy within 20 days of feeding.
   Branch  toxicologists have  assessed  the significance  of the
studies  undertaken  at  the  National  Institute  of  Nutrition,
Hyderabad,  India  and  consider that  the  following  points are
relevant  in connection  with evaluation  of the  study involving
undeI/{;]rished Indian children:
(a)  Malnourished children are not considered to be the best test
     subjects  available, since  malnutrition  alone is  known to
     induce chromosomal aberrations.  Furthermore, the background
     incidence  of  chromosomal  aberrations  among  malnourished
     children may vary because it may be affected by the type and
     degree of malnutrition.  No data on the background incidence
     of chromosomal  aberrations in  malnourished Indian children
     were provided.
(b)  The fact the  study reported increased  polyploidy (1.8%) in
     the    lymphocytes    of     malnourished    children    fed
     freshly-irradiated  (0.75  kGy) wheat,  but  none  (0.0%) in
     children fed  unirradiated wheat is  unusual.  Armendares et
     al., (1971) reported that malnourished Mexican children (age
     1-60  months)  exhibited  a  high  incidence  of chromosomal
     aberrations   (12-21%)  in   lymphocytes  relative   to  the
     background   incidence   of   chromosomal   aberrations   in
     lymphocytes of well-fed children (2-4%).
   Health Protection  Branch toxicologists have  noted other work
which is  of relevance  in addressing  the polyploidy  issue.  In
particular,  Brynjolfsson (1986)  has  summarized the  results of
eight experiments  conducted in  China in  which foods irradiated
from 0.1 -  8.0 kGy were fed  to a total  of 439 human volunteers
for a  7 to  15 week period.  These experiments,  which have also
been  cited in  a  recent [page  24]  report of  the  Council for
Agricultural  Science  and Technology  (1986),  were  reported to
reveal no increase in  the incidence of polypoidy.  In a study by
Renner  et  al.  (1982)  no  chromosomal  aberrations,  including
polypolidy, were observed  in the bone marrow  of male and female
Chinese hamsters fed  irradiated cooked chicken  (7.0 kGy, stored
5-8 days), dried dates (1.0 kGy)  or cooked fish (2.5 kGy, stored
7-10 days) for a period of  6 days.  Although an earlier study by
Renner (1977) showed  that a commercial  diet, freshly irradiated
at 30-45 kGy and fed to Chinese hamsters for a period of 1 day or
6 weeks, did  increase the incidence of  polyploidy cells in bone
marrow  3-5 times  that  of controls  (controls  0.06 -  0.08% vs
treated 0.20  - 0.32%)  the same  diet irradiated  at dose levels
below  20  kGy   caused  no  increase   in  polyploidy  of  other
chromosomal aberrations.
   Based  on  all of  the  above considerations,  the  Branch has
concluded that consumption of wheat  irradiated up to the maximum
absorbed dose permitted  in Canada for  this commodity (0.75 kGy)
would not pose a hazard to the consumer.
(21) The  results of 12  United States  Department of Agriculture
(U.S.D.A.)  sponsored studies  were  cited by  one  respondent in
which chicken  was exposed "to  the same levels  of radiation (56
kGy) being considered  for future approval  of meat and poultry".
The  respondent  indicated  that   there  were  several  findings
indicating the  toxicity of  irradiated chicken  fed to  mice, in
particular, the following noted in one of the studies:
1.   A "statistically significant" increase  in testicular tumors
     in mice fed Cobalt-60 (gamma) irradiated chicken meat (Group
[Page 23]
2.   Survival  of  both  sexes  in   this  group  (Group  G)  was
     significantly  reduced,  at  least  in  certain  sub-groups,
     compared to the controls.
3.   Many lesions (including  cancer) which occurred infrequently
     and for which  statistical analyses could  not be performed,
     were often found most frequently in this group (Group G).
4.   Thus, while  there is no  evidence of a  highly toxic effect
     from  diet G,  the preponderance  of evidence  suggests some
     degree of toxicity was present.
   The respondent  also expressed concern  about "the significant
adverse effect  in Group G  mice involving  immune kidney disease
("glomerulonephropathy")".  Finally, the  respondent mentioned "a
statistically significant dose-related increased rate of death in
the offspring of flies fed gamma-irradiated chicken", this effect
cited as being "consistent with chromosomal damage".
   It should be indicated that  the branch has not considered nor
is presently considering submissions  for the irradiation of meat
and  poultry  at 56  kGy.  This  is a  sterilizing  dose  and the
particular  studies  cited  by  this  respondent  were undertaken
primarily  to  asses  the feasibility  and  safety  of preserving
military rations in which the  radiation treatment was applied to
a canned, frozen product  containing added salt.  Most commercial
interest in irradiating chicken  has been and is  likely to be in
irradiating fresh  or frozen  whole birds  or comminuted [ground,
pulverized] chicken meat at doses sufficient to reduce Salmonella
contamination.  The doses are below  10 kGy, usually ranging from
3-7 kGy.
   Concerning   the   first  finding   mentioned   above,  Health
Protection   Branch  toxicologists   have  reviewed   this  study
thoroughly [page 26] and  Branch statisticians have subjected the
testicular interstitial cell tumour incidence data to statistical
analysis.   As  a  result,  it   was  found  that  there  was  no
statistically   significant  difference   in  the   incidence  of
interstitial  cell  tumors   in  the  male   mice  of  gamma-  or
electron-irradiated  meat  groups when  compared  to  the control
(frozen  meat) group.   A committee  of Health  Protection Branch
Pathologists examined  microslides of testicular  tissue from the
animals  considered to  exhibit possible  tumorigenicity.  Branch
pathologists agreed with the  conclusions reached by other review
groups, namely, that  the observed benign  testicular tumors were
not  treatment-related.  The  Health Protection  Branch concludes
that the available evidence does not support the view that benign
testicular interstitial cell tumours,  observed in male CD-1 mice
in the  evaluated study are  related to consumption  of gamma- or
electron-irradiated chicken meat.

Note: To  assist  the  reader in  the  following  discussion, the
      following designations  for the  various diets  employed in
      the mouse irradiated chicken study were used:
      Group N (laboratory chow)
      Group F (35% frozen chicken meat; 65% laboratory chow)
      Group   T  (35%   thermally-processed  chicken   meat;  65%
              laboratory chow)
      Group G (35% gamma-irradiated  chicken meat; 65% laboratory
      [Page 27]
      Group   E  (35%   electron-irradiated  chicken   meat;  65%
              laboratory chow)

   The second issue related to decreased survival of mice.  While
survival  was similar  in all  experimental  groups at  15 months
treatment, it decreased considerably after 15 months on test.  At
the end  of the  test period (24  months) the  survival among all
groups of  mice fed laboratory  chow/chicken meat  was lower than
those fed only laboratory chow (Group N). But in this experiment,
it  is really  appropriate  to consider  Group  F as  the control
group, because  this diet unlike  Groupe [sic]  N contained (35%)
chicken meat.  While the females in the "non breeder" (i.e. those
animals used only  in the chronic/carcinogenicity  study) Group G
had a lower percentage survival  than the other comparable groups
(F,  T  and E),  the  various parameters  measured  for assessing
toxicity (i.e.  body weights, hematology,  blood chemistry, gross
pathology) did not  support a treatment-related  effect.  It must
also  be noted  that the  percentage survival  of females  in the
"breeder" (i.e.  those animals used  to produce  F1 progenies for
the   multi-generational    study   and   then    used   in   the
chronic/carcinogenicity study) Group G  was the highest among the
other comparable groups (F, T and E).  One must consider that the
"breeder" Group G  mice may have consumed  more diet (to maintain
pregnancy)  that the  "non-breeder"  Group G,  and  if irradiated
chicken was  responsible for  decreased survival,  one would have
also expected higher mortality in the "breeders".  Furthermore in
similar studies  with rats and  dogs, survival  was not adversely
affected by  consuming diets containing  irradiated chicken meat.
Thus,  there   is  scientific   justification  to   consider  the
percentage  survival in  the female  "non-breeder"  Group G  as a
spurious result.   Such an  [page 28]  occasional spurious result
can  reasonably  be   expected  when  biological   data  from  20
experimental groups are collated.
   Concerning  the  third  issue on  frequency  of  occurrence of
lesions,  it  should  be  indicated  that  spontaneous neoplastic
lesions  (including  cancer)  were  observed  among  mice  of all
experimental  groups  of   either  "breeders"  or  "non-breeders"
subgroups.   The incidence  of  lesions was  not  associated with
ingestion of irradiated  chicken meat.  As a  matter of fact, the
highest incidence of total  neoplastic lesions was observed among
control animals fed frozen chicken meat (Group F).  The frequency
of lesions  observed was  within the  range of  normal biological
incidence for this strain of mice.
   The  fourth point  raised by  this  respondent was  that while
there is  no evidence  of highly  toxic effect  from diet  G, the
preponderance of  evidence suggests  some degree  of toxicity was
   Based  on  an  extensive  toxicological  review,  it  has been
concluded  that  the  experimental  data  do  not  demonstrate  a
treatment-related toxicological effect.
   Concerning immune  kidney disease  (glomerulonephropathy), the
incidence  of non-neoplastic  lesions  of kidney  was  high among
animals of all experimental groups.
[Page 29]
   The  data showed  that  the incidence  of  the lesion  was not
associated with ingestion of irradiated chicken meat.  Again, the
highest incidence of  the lesions was  observed among animals fed
frozen chicken meat (see below).

Incidence (%) of kidney glomerulonephropathy for combined data
                 ("breeders" and "non-breeders")

                                      Males   Females

Group N (laboratory chow)              8.2      22.4
Group F (Frozen chicken meat)         19.5      37.9
Group T (thermally processed meat)     9.0      29.2
Group G (gamma-irradiated meat)       15.0      35.8
Group E (electron-irradiated meat)    15.7      33.9

   Finally,  in  regard  to this  respondent's  concern  about an
increased  rate of  death  in the  offspring  of flies  reared on
gamma-irradiated  chicken  meat,  the  study  of  the  sex-linked
recessive  lethal   test  in   Drosophila  melanogaster  produced
non-mutagenic  effects.   However,  a  significant  reduction  in
production of offspring  (reproductive effect) in  cultures of D.
Melanogaster,  reared   on  gamma-irradiated   chicken  meat  was
observed.  A similar but much lower response occurred in cultures
reared on the frozen chicken meat. The toxicological significance
of  this  finding  is  doubtful  as  far  as  man  is  concerned.
Extrapolation of the findings from  the D. Melanogaster fly study
to the human being is very difficult.  Furthermore, the number of
reproduction studies with experimental  animals (mouse, rat, dog)
reviewed  by the  Branch clearly  demonstrated that  ingestion of
different  [page 30]  irradiated foods  did not  adversely affect
reproductive parameters investigated. ...
[Page 32]
(25) ...  In assessing the  human health  implications of dietary
exposure to irradiated foods,  all available information has been
reviewed.  Many countries,  for example, Belgium,  Japan, and the
Netherlands (International Atomic  Energy Agency; November, 1986)
have had experience in irradiating individual food items, without
reports of adverse effects on the human population. ...

[Sections  `Record-Keeping  Requirement' and  `Table  of Positive
Listings' omitted.   `Introduction to  `Comments Not Specifically
Related to I.L. No. 651' omitted.]

[Page 35]
(1)  The  comment  has  been made  that  foods  subjected  to the
irradiation process become radioactive.
   Using  electronic  or  machine sources  to  produce  X-rays or
electron beams, it  is possible to  induce radioactivity in foods
if such  sources are  operated at  high energy  levels.  For this
reason, constraints have  been proposed for  the energy levels of
these types of radiation (5 MeVs for X-rays; 10 MeVs for electron
beams).     At    these    controlled    energy    levels,    the
experimentally-measured   and   possible   theoretically  induced
activity  is  several  thousand   times  less  than  the  natural
background level of radioactivity in food.
   The inherent energy levels  of gamma-rays emitted by Cobalt-60
and Cesium-137 are too low to cause induced radioactivity.
   For the reasons outlined above, irradiated foods do not become
radioactive as a result of this treatment.
[Page 36]
(3)  The  argument  has  been  made  that  the  Chernobyl nuclear
disaster [26 April 1986]  experience illustrated the dangers that
can result from irradiating food.
[Omitted paragraph  states that  radionuclides may  be harmful to
human tissues when inhaled or ingested.]
   In the case  of irradiated food,  the radionuclide source does
not come in  contact with food.   Rather, the food  is exposed to
gamma-rays emitted by the source  material.  Thus, in the context
of contamination  of food  by radionuclides,  comparisons between
the  Chernobyl   nuclear  disaster   and  food   irradiation  are
inappropriate and misleading.
[Page 37]
(4) Concern has been voiced  about the production and persistence
of free radicals.
   The  formation  of  free  radicals   is  not  unique  to  food
irradiation.  Indeed, free radicals are  formed by other types of
physical processing  of food such  as cooking  and canning.  Free
radicals  are  generally  very  short-lived  in  the  presence of
moisture and do  not persist in foods.   Even so-called dry foods
such as wheat contain significant amounts of water (15%) and free
radicals would  not be  expected to  persist for  any appreciable
time  in such  a medium.   In fact,  in a  study by  Diehl (1972)
whereby starch  (the major  constituent of  wheat) containing 15%
moisture was  irradiated at  a dose  of 10  kGy, no  free radical
activity could be detected within  one day of irradiation.  Thus,
in relation  to the existing  provisions the  likelihood of there
being any free radicals present  in food as consumed is extremely
remote. ...
(5)   It  has   been   suggested  that   altered  microbiological
populations  can  cause   radiation-resistant  microorganisms  of
public health concern to multiply due to lack of competition from
those destroyed.
   The oft-cited example  used to support  this contention is the
assumption   that   relatively   radiation-resistant  Clostridium
botulism spores will  grow unabated in food  irradiated at 10 kGy
due to competitor spoilage organisms being destroyed.  Like other
conventional   non-sterilizing    processing   techniques   (e.g.
pasteurization), irradiation  up to  10 kGy  will not  destroy C.
botulism spores.  As  is the case  following application of these
other  techniques,  proper storage  and  refrigeration conditions
must  be employed  to [page  37] ensure  against outgrowth  of C.
botulism spores, if present.
   The Board of the  International Committee on Food Microbiology
and  Hygiene  of  the   International  Union  of  Microbiological
Societies at  their meeting  in Copenhagen,  1982, also concluded
that the alteration of microbial populations after irradiation is
similar to that  which occurs after  other conventional processes
such as pasteurization.  The Board  viewed food irradiation as an
important additional  process to control  foodborne pathogens and
did not present any additional health hazards. ...
(6) It  has been  alleged that the  process can  lead to enhanced
aflatoxin production by microorganisms.
   This  allegation  may  be  based  on  a  laboratory experiment
(Schindler et al., 1980) which showed apparently higher aflatoxin
production  of   irradiated  spores.   This   experiment  is  not
considered  to be  relevant to  food  irradiation because  it was
carried  out  under  conditions  not  encountered  in  commercial
practice.   Also, some  studies have  shown that  the irradiation
process itself can actually destroy aflatoxin and other toxins in
food (Temcharoen and Thilly, 1982; Jaddou et al., 1983).

                   [Selected references only.]

1.   Advisory Committee on Irradiated and Novel Foods.  Report on
     the Safety  and Wholesomeness of  Irradiated Foods.  London,
     1986.  Her Majesty's Stationery Office, P.O. Box 276, London
     SW8 5DT.
2.   Armendares,  S.,   Salamanca,  F.   and  Frenk,   S.   1971.
     Chromosome   abnormalities   in   severe   protein   calorie
     malnutrition.  Nature 232: 271-273.
5.   Bhaskarem, C. and  Sadasivan, G.  1975.   Effects of feeding
     irradiated  wheat to  malnourished  children.  Am.  J. Clin.
     Nutr., 28: 130-135.
7.   Brynjolfosson,  A.   1987.   Results  of  feeding  trials of
     irradiated diets in human volunteers: Summary of the Chinese
     studies  reported  at  FAO/IAEA  seminar  for  Asia  and the
     Pacific on  the practical application  for food irradiation.
     Food Irradiation Newsletter, 11(1): 33-41.
8.   Cotchin, E. and Roe,  F.G.C.  1967.  Pathology of Laboratory
     Rat and Mice. p. 781.
9.   Council for  Agricultural Science  and Technology.  Ionizing
     Energy   in   Food   Processing   and   Pest   Control:   I.
     Wholesomeness of  Food Treated With  Ionizing Energy.  Ames,
     Iowa,  1986.  Report  No. 109.   Available from  Council for
     Agricultural Science and Technology,  137 Lynn Avenue, Ames,
     Iowa  50010-7120.
10.  Diehl, J.F.  1972.  Elektronenspinresonanz-Untersuchungen an
     strahlenkonservierten   Lebensmitteln.    11.   Einfuss  des
     Wassergehaltes  auf  die  Spinkonzentration.  Lebensm.-Wiss.
     Technol., 5: 51.
11.  Goodman,  D.G.,  Ward,  J.M., Squire,  R.A.,  Chu,  K.C. and
     Linhart, M.S.  1979.   Neoplastic and non-neoplastic lesions
     in aging F344 rats.  Toxicol. Appl. Pharmacol.  48: 237-248.
13.  International   Atomic   Energy   Agency.    November  1986.
     "Commercialization of Food Irradiation".  Article from: Food
     Irradiation Newsletter 2(10): 48-52.
14.  Ivanov,  A.E.  and  Levina,  A.I.   1981. Pathomorphological
     changes in  the testes  of rats  fed on  products irradiated
     with gamma-rays.  Byull. Eksp. Biol. Med. 91(2): 233-236.
15.  Jaddou, H., Al-Hakim,  M., Al-Adamy, L.Z.  and Mhaisen, M.T.
     1983.  Effect  of gamma-radiation on  gossypol in cottonseed
     meal.  J. Fd. Sci., 48: 988-989.
16.  Levina, A.I. and Ivanov, A.E.  1978.  Pathomorphology of the
     kidneys  in  rats after  prolonged  ingestion  of irradiated
     foods.  Byull. Eksp. Biol. Med. 85(2): 230-232.
17.  Renner, H.W.  1977.  Chromosome studies on bone marrow cells
     of Chinese hamsters fed  a radiosterilized diet.  Toxicology
     8: 213-222.
18.  Renner,  H.W.,  Graff,  U.,   Wurgler,  F.E.,  Altmann,  H.,
     Asquith, J.C.  and Elias,  P.S.  1982.   An investigating of
     the  genetic  toxicology   of  irradiated  foodstuffs  using
     short-term test systems.  III-In vivo tests in small rodents
     and  in  Drosophila Melanogaster.   Fd.  Chem.  Toxicol. 20:
19.  Schindler,  A.F.,  Abadie,  A.N.  and  Simpson,  R.E.  1980.
     Enhanced  aflatoxin  production  by  Aspergillus  flavus and
     Aspergillus parasiticus after gamma irradiation of the spore
     inoculum.  J. Fd. Prot., 43: 7-9.
20.  Temcharoen,  P.  and  Thilly,  Wm.  G.   1982.   Removal  of
     Aflatoxin  B1 toxcicity  but not  mutagenicity by  1 megarad
     gamma  irradiation  of  peanut  meal.   J.  Food  Safety, 4:
22.  U.S. Food and Drug Administration.   1986.  21 CFR Part 179.
     Irradiation in  the Production, Processing,  and Handling of
     Food; Final Rule.  Federal Register, 51(75): 13376-13399.
23.  Vijayalaxmi, C.   1978.  Cytogenetic studies  in monkeys fed
     irradiated wheat.  Toxicology, 9: 181-184.
24.  World  Health  Organization.   Wholesomeness  of  Irradiated
     Food.   Geneva, 1981.   World Health  Organization Technical
     Report Series No. 659.

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