Alternatives to Antibiotics
Mark E. Cook, FRI and Dept. Animal Sciences
In the 1950s, researchers showed that animals raised in germ-free environments
grew more rapidly than those raised in the presence of normal bacterial
flora. At the time of these early studies, it was unclear why an animal's
exposure to bacteria suppressed growth and decreased feed efficiency. However,
it was clearly shown in these early studies that animals given antibiotics
showed improved growth when exposed to environmental microbes, but not
when raised in germ-free environments. Hence the use of antibiotics as
growth promotants and as a method to improve feed efficiency became commonplace
in modern animal agriculture. Antibiotic use has had its controversy, and
while many hypotheses were developed to explain the growth promotant, none
seemed to withstand scientific testing.
In the 1980s, research began to show that growth depression due to exposure
to environmental microbes was not caused by the microbes themselves, but
instead was due to the animal's immune response. Immune cells, upon encountering
a foreign stimulant, release peptide signals (cytokines) which profoundly
alter physiological processes. Cytokines released during an immune response
stimulate skeletal muscle catabolism, increase select protein synthesis
in the liver, induce anorexia (decreased food intake) and cause fever.
As a result, the immune-stimulated animal eats less and grows more slowly.
Feeding antibiotics reduces the concentration of immune stimulants and
thus lowers cytokine production, hence antibiotics improve growth by reducing
immune stimulation.
Concern has increased that feeding low levels of antibiotics is generating
antibiotic resistance. We have sought alternative approaches to improve
growth in immune stimulated environments. Attempts to remove immune stimulation
(in this case, bacteria) results in microbial resistance. Suppression of
the immune system is not a wise approach (even though we know it will enhance
growth) because of the resulting susceptibility to invading pathogens.
We were left with only one avenue to enhance growth: alter the animals'
physiological response to cytokines. In previous newsletters, we have written
of several technologies (conjugated linoleic acid and mass antibody production).
We believe strategies that alter the animal's response to its immune system
will result in improved methods to stimulate growth and improve feed efficiency
without the use of antibiotics.
| Immunoassays of Selected
Mycotoxins in Hay, Silage and Mixed Feed: An Entrée to Significance
of Mycotoxin Level on Animal Health and Performance |
|
While foods and feeds contaminated with certain mycotoxins are potentially
hazardous to human and animal health, the presence of sub-lethal levels
of mycotoxins often results in a decrease in immune response, loss of body
weight and decrease in productivity of farm animals. One of the problems
frequently encountered by the use of moldy feed is a decrease in milk production,
and sometimes body weight loss. It is not known which mycotoxins, or group
of mycotoxins, is responsible for the decrease in productivity. There is
need for a systematic survey on the relationship of the health status of
the animals to feed quality, fungi population and mycotoxin content in
the feeds. Analysis of feeds is difficult because feeds constitute a very
complex matrix. In the present study, several immunoassays, including radioimmunoassay
(RIA) and direct competitive enzyme linked-immunosorbent assays (dc-ELISAs),
for the analysis of the mycotoxins Alternaria alternata (AAL), cyclopiazonic
acid (CPA), deoxynivalenol (DON), fumonisin B1 (FmB1), PR toxin (PRT) and
zearalenone (ZEA) in hay, silage and mixed feed were established. The toxins
were extracted from the feed with 84% acetonitrile in water, then the filtrates
were diluted with buffer and directly subjected to dc-ELISA for AAL toxin,
CPA, FmB1, PR and ZEA. For total DON including DON, 15-acetyldeoxynivalenol
(15-AcDON), and 3-acetyldeoxynivalenol (3-AcDON), the extracts were air-dried,
acetylated, and subjected to both RIA and dc-ELISA. The average percent
recoveries of toxins added to hay at 0.3 and 1.0 ppm were 77.5, 111, 95.8,
85.7, 95.5 and 138 for AAL-toxin, DON, CPA, FmB1, PRT and ZEA, respectively.
When the sample extracts were subjected to a C-18 reversed-phase cartridge
treatment prior to dc-ELISA, the recovery of ZEA at 0.1 and 1.0 ppm levels
was found to be 111 and 75%, respectively. Analysis of 63 samples (25 hay
and 38 others, including corn silage and mixed feed) showed frequencies
of AAL toxin, DON, CPA, FmB1, PRT and ZEA were 96.8, 100, 87.3, 36.5, 76.2
and 3.2%, respectively. The overall average concentrations of toxins in
the feed were 0.56, 0.73, 0.34, 0.28, 0.13 and 0.22 ug/g (ppm) for AAL
toxin, DON, CPA, FmB1, PRT and ZEA, respectively. For hay alone, the frequencies
were 100 (average level of 0.72 ppm), 100 (average level of 0.61 ppm),
80 (0.39 ppm), 52 (0.12 ppm) and 80% (0.15 ppm) for AAL, DON, CPA, FmB1
and PRT, respectively. Zearalenone was not found in the hay samples. Data
from the present limited survey showed that: (i) while low levels of mycotoxins
were present, only a few samples were contaminated with high levels of
DON and FmB1, primarily in the corn-related products; (ii) the presence
of AAL toxin, CPA and PR toxins indicates clearly that toxic fungi of the
genera Alternaria, Aspergillus and Penicillium were present
in the hay and corn silage in addition to the several species of Fusarium;
(iii) although our limited data cannot lead to any conclusion on whether
the performance of animals was affected by these low levels, the established
methods are adequate for a systematic study to learn if low levels of mycotoxins
are related to the decreased milk production, or are affecting any other
performance in farm animals.
—W. Yu, F. Y. Yu, D. Undersander, and F. S. Chu
| Monitoring of Microcystin–Protein
Phosphatase Adduct Formation with Immunochemical Methods |
|
Algal blooms have become a growing public health problem worldwide in recent
years because some of the secondary metabolites produced by them are toxic
to mammals. In freshwater lakes or waterways toxic blue green algae (cyanobacteria)
blooms frequently occur. These algae produce products called microcystins
and nodularins which are cancer promoters and cause liver damage, gastroenteritis,
diarrhea, and dermatitis in animals and humans. In addition to water, MCYSTs
were also found in health food algal products, which may have a potential
health hazard to users. Mechanistically, MCYST-LR, one of the major variants
in this group of toxins, is a potent inhibitor of protein phosphatase (PPase)
1 (PP1) and 2A (PP2A). The inhibitor effect is due to its interaction with
the enzyme through covalent binding and free form. We have developed a
series of specific antibodies against MCYSTs, as well as a sensitive immunoassay
for the toxin. In the present study, an immunoblotting method was developed
to monitor the adduct formations both in vitro and in vivo. The detection
limits for the covalent binding of MCYST-LR with the recombinant protein
phosphatase 1 (PP1) and rabbit liver cytosol proteins were found to be
0.1 ng and 0.3 ng per assay, respectively. MCYST-PP1 adducts were detected
30 seconds after the addition of MCYST-LR into the reaction mixture. Immunoblotting
analyses and enzyme-linked immunosorbent assay showed that between 5 min
to 16 hr after i.p. injection of a single dose (35 ug/kg) of MCYST-LR into
mice, up to 27% of the injected toxin was found covalently bound while
0.2–9.2% existed free form in liver cytosol. Our data suggest that the
newly developed method could be used for monitoring MCYST intoxication
in humans and animals.
—Biing-Hui Liu, Feng-Yih Yu, X. Huang, and Fun Sun
Chu
| Life in Acid: What Can We Learn
from Bacteria That Thrive in Extreme Environments? |
|
The National Science Foundation recently announced awards to further our
knowledge of "Life in Extreme Environments" (LexEn). It is thought that
this new information will help understand the beginnings of life on this
planet and others, and develop new technologies and processes. An interdisciplinary
group of researchers at the University of Wisconsin–Madison was selected
to study Life in Acid. The group is led by Dr. Jillian Banfield from the
Department of Geology and Geophysics, and includes Brian Fox, Department
of Biochemistry, Institute for Enzyme Research, and Charles Kaspar, Department
of Food Microbiology and Toxicology, Food Research Institute. The 3-year
project will identify and monitor the microbes present in dissolving pyrite-rich
deposits (FeS2, natural sulfide mineral) which contain metal-rich,
sulfuric acid solutions with pH values of 0–2. Why is this of interest
to food microbiologists? FRI Director Emeritus Mike Foster stated it best
when he said, "Food microbiology is nothing more than an extension of environmental
microbiology." The recognition of the acid-tolerance properties of Escherichia
coli O157:H7 following outbreaks involving acidic foods such as apple
cider, dry-fermented salami, mayonnaise, and yogurt has driven research
to find the physiological and structural components that contribute to
this tolerance to low pH. Moreover, it is hypothesized that tolerance to
gastric acidity permits low-infectious dose pathogens, like E. coli
O157:H7 and others, to bypass this gastric barrier. Thus, understanding
the growth and/or survival in acid by microbes in extreme environments
may shed insight on acid tolerance in foodborne pathogens. Dr. Banfield's
laboratory will employ standard culture methods and DNA sequencing to identify
iron-oxidizing bacteria associated with drainage from Iron Mountain mine
near Redding, California. The drainage from this site is highly acidic
(pH <1.0) and contains Fe>21,000 mg/L, Zn >2,000 mg/L, Cd >16 mg/L,
Cu >200 mg/L, and As >47 mg/L. Previous analyses of this site have isolated
Leptospirillum, Ferromonas, and Acidomicrobium spp. that
will be metabolically characterized. Chuck Kaspar of FRI will investigate
the influences of membrane lipid composition on survival in acidic solutions
with high ionic strength. Proteins involved in iron oxidation, enzymes
and cytochromes among these divergent organisms will be characterized in
detail by Brian Fox's laboratory to determine if there is a common or unique
respiratory chain present. In addition to understanding the mechanism of
acid tolerance, the research may identify enzymes, molecules, or organisms
of commercial significance.
—Charles W. Kaspar
| Detection of Food Allergens |
|
Allergens in foods pose a major problem for the food-allergic individual.
Labeling of food products for the presence of food allergens is at present
the most effective way for the food-allergic person to prevent reactions.
Food processors are concerned about the possibility of cross-contamination
of products by food allergens. This is especially true when a manufacturer
runs a product containing a known food allergen through its equipment,
and following a clean-up operation, runs another product which does not
contain any allergens. How are the processors and consumer to know if the
nonallergic product has become contaminated? To answer this question a
number of laboratory tests have been conducted, and the development of
assays which can be used by the processor to detect food allergens is coming
into commercial use. Since peanuts, eggs, and milk are among the most important
sources of food allergens in the United States, most efforts have been
directed at detecting these allergens. In the research laboratory, the
RAST (radio-allergosorbant) inhibition assays have been widely used. This
immunoassay employs serum from food-allergic individuals and utilizes a
radioactive-labeled antibody to IgE for the detection of the allergen.
While useful in the research laboratory, the limitations imposed by the
use of human serum and radioactivity prevent its commercial use by the
food industry. Other approaches that have recently become commercially
available employ an ELISA (enzyme-limited immunoassay) technique that utilizes
polyclonal antibodies raised in rabbits. Assays are available for peanut
(Pro-Lab Diagnostics, United Kingdom; Neogen Corporation, Lansing, MI;
and ELISA Technologies, Alachua, FL) and egg (Neogen). Detection limits
for the assays range from 0.1 ppm for peanut (Pro-Lab) to 1–2 ppm (Neogen)
and 0.5 ppm for egg (Neogen). These assays generally can be performed in
45 minutes and avoid the use of radioactive materials. Other assays are
available for peanut and egg (Neogen), but the sensitivity levels are higher
(2.5–25 ppm). Our laboratory has utilized a PCR (polymerase chain reaction)–monoclonal
antibody-based assay that has an extremely low level of detection. However,
this is only a research tool at present. While the use of immunoassays
potentially can reduce the risk of reactions for the food-allergic consumer,
many questions still remain. Are the assays sensitive enough or are they
too sensitive? Are the assays applicable to a wide variety of food matrices
that can affect the results? What are the legal implications of testing?
Many technical, legal, and ethical questions need to be addressed.
—Robert K. Bush
| Natural Antimicrobial Components
Isolated from Yerba Maté (Ilex paraguariensis) |
|
Ilex paraguariensis St. Hilaire var. paraguariensis is a
South American native perennial tree belonging to the holly family (Aquifoliaceae).
South American inhabitants have used it as a refreshing stimulant tonic
drink (prepared by infusion of its dried leaves and twigs) long before
Jesuits recorded the habit in the sixteenth century. Although in many South
American countries it is drunk more frequently than any other beverage,
maté, erva-maté or yerba maté as it
is called as only recently become known in Europe has an alternative to
Indian or Chinese tea. The leaves are also used in popular medicine, and
included in medicinal herbal products as a tonic, stimulant to the central
nervous system, diuretic and antirheumatic. It contains a significant amount
of secondary metabolites such as caffeine, triterpenes, caffeoylquinic
acid derivatives (chlorogenic acid), purine alkaloids and methylxanthines.
The crude extract of yerba maté exhibited antimicrobial activity
against both gram-positive and gram-negative bacteria such as Staphylococcus
aureus, Listeria monocytogenes, Escherichia coli O157:H7, Salmonella
typhimurium, and Pseudomonas fluorescens. The antimicrobial
compounds were identified as dicaffeoylquinic acid derivatives, monocaffeoylquinic
acid derivatives, methylcaffeate and caffeic acid. Three isomers of monocaffeoylquinic
acids were isolated and identified as 3-O-caffeoylquinic acid, 4–O-caffeoylquinic
and 5-O-caffeoylquinic acid. Likewise, three isomers of dicaffeoylquinic
acids were revealed as 3,4-O-dicaffeoylquinic acid, 3,5-O-dicaffeoylquinic
acid and 4,5-O-dicaffeoylquinic acid. This is the first report of
caffeic acid and methylcaffeate in yerba maté. All of the
antimicrobial compounds were extracted from dried leaves with 25% methanol
and isolated by flash column chromatography, preparative TLC and reversed
phase HPLC. The antimicrobial properties of monocaffeoylquinic acids, dicaffeoylquinic
acids and methylcaffeate were conducted in microtiterplates by microdilution
assay. All of them showed inhibitory effects against all bacteria tested
but methylcaffeate was the most effective antimicrobial component in the
inhibition of food-related bacteria. These compounds were most inhibitory
at pH 8.0 and still retained the inhibitory activity after heat treatment
at 121C for 15 min.
—Tipparat Hongpattarakere and Eric A. Johnson
| Chu |
Travels in China:
Dr. Fun S. Chu was invited by the Institute of
Nutrition, Food Hygiene and Food Safety of Chinese Academy of Preventive
Medicine (CAPM) to Beijing, China, in June to give a keynote speech on
recent progress of mycotoxin research. He also gave a series of lectures
on the application of immunochemical assays for mycotoxins in a workshop
entitled "National Workshop on Immunochemical Methods for the Detection
of Mycotoxins in Foods and Feed." Participants in this workshop were mostly
from the CAPM and from Provincial Anti-Epidemic and Preventive Stations,
and Food Inspection Stations. Discussion were held on various mycotoxin
problems and preventive measures for minimizing the problem in China. |
| Wong |
Presentations and posters by Professor
Amy C. Lee Wong:
"Tri(ethylene glycol) dimethyl ether and 12-crown-4-ether
plasma coating of stainless steel to prevent bacterial attachment and biofilm
deposition." Agnes R. Denes, Eileen B. Somers, Amy C.
L. Wong, and Ferencz Denes [Poster]. Center for Plasma-Aided
Manufacturing Annual Meeting/Workshop, July 7-8, 1999, UW–Madison campus.
"Tripartite hemolysin BL: experimental and predictive analysis of structure
and function." Douglas J. Beecher and Amy C. Lee Wong [Talk].
"Requirement of flhA for flagella assembly, swarming differentiation,
phospholipases and hemolysin BL secretion in Bacillus thuringiensis."
E. Ghelardi, D. J. Beecher, F. Celandroni, M. Pastore,
A. C. L. Wong, D. Lereclus and S. Senesi. This is
a collaborative research effort between the University of Pisa, Italy,
and our lab [Talk]. "Heterogeneity observed in hemolysin BL, a tripartite
enterotoxin produced by Bacillus cereus." Jean L. Schoeni
and Amy C. Lee Wong [Poster]. 2nd International Workshop on the
Molecular Biology of Bacillus cereus, Bacillus anthracis
and Bacillus thuringiensis in Taos, New Mexico, August 11-13, 1999.
Visitor:
Dr. Emilia Ghelardi from the University of Pisa,
Italy, visited Wong's lab for three weeks (July 19–August 9) to continue
our collaboration to determine whether the swarming phenotype of Bacillus
cereus and Bacillus thuringiensis is related to the expression
of virulence factors. Emilia also visited us for six weeks last fall.
Summer Research Program:
Participated in the UW–Madison Summer Research Program
for Undergraduates in Biology, and had a student, Lai Thao, in a
research project on resistance of biofilm bacteria. Lai is also a Ronald
E. McNair Scholar. |
| Cook |
Talks by Mark Cook:
May 25–27, 1999. "Conjugated linoleic acid." Multi-state
Poultry Feeding and Nutrition Conference and Degussa Technical Symposium.
Indianapolis, IN.
May 28–June 2, 1999. "Conjugated linoleic acid and health."
International Conference on Diet and Prevention of Cancer. Tampere, Finland.
June 22, 1999. "Conjugated linoleic acid." The Reciprocal
Meat Conference. Stillwater, OK. |
| Johnson |
New Personnel:
Stephanie Whittum has joined Johnson's laboratory
to study Clostridium botulinum for her M.S. and Ph.D. This past
summer, she performed an internship at the Pillsbury Company. Prior to
that she attended Ohio State University and majored in microbiology. Kendra
Thornton spent the summer in Johnson's laboratory in the National Science
Foundation sponsored program Research Experience for Undergraduates (REU)
in the Department of Bacteriology.
Graduated Personnel:
Carlos Echavarri Erasun received his M.S. in Bacteriology
in July 1999. The subject of his thesis was the "Regulation of Astaxanthin
Biosynthesis in the Yeast Phaffia rhodozyma.
Papers and Symposia presented by Professor Johnson:
An invited seminar entitled "Improving microbial detection
towards ‘Real Time' in the Symposium "Research Goals of the National Food
Safety Initiative" at the Ninty-ninth General Meeting of the American Society
for Microbiology, Chicago, IL. An invited paper at the Annual Meeting of
the Institute of Food Technologists in Chicago in July entitled "Consequences
of stress and resistance responses during food processing."
Chaired a session on "Microbial toxins as therapeutic
agents" and presented two papers at the Society for Industrial Microbiology
meeting in Arlington, Virginia, in August 1999. The titles of his papers
were "Botulinum toxin as a therapeutic agent" and "Regulation of astaxanthin
biosynthesis in the yeast Phaffia rhodozyma."
Awards:
Johnson has received a three-year research grant from
the National Institutes of Health entitled "Regulation of Botulism Toxin."
A two-year grant from the USDA entitled "Novel Antimicrobial Systems for
Inactivation of Microbial Pathogens." Two grants from University–Industry
Relations (UIR): "Development of Terpenoids from Wisconsin Agricultural
Products to Sensitize Microorganisms to Antimicrobials" and "Determination
of Neuron Targeting Sequences of Botulinal Neurotoxin using Synthetic Mimetic
Compounds." |
| Foster |
Invited presentation by E.M. Foster:
"Food microbiology research: The road ahead" in a colloquium
"Pasteur to the Present: a Food Microbiology Retrospective and Prospects
for the Future" at the Ninty-ninth General Meeting of the American Society
for Microbiology, Chicago, IL. |
| Workshop |
The Center for Dairy Research and FRI
jointly sponsored and managed a dairy food safety workshop on September
1, 1999. About 35 people attended, primarily plant personnel. |
| Visitors |
|
Bel/Kaukauna, USA and Fromageries/Bel S.A. |
Research, development
and engineering staff from Bel/Kaukauna, USA and Fromageries/Bel
S.A., France, were here to discuss ongoing projects of mutual interest,
particularly regarding cheese safety.
Back row, L to R:
K. Anjan Reddy, Technical Director Bel/Kaukauna USA (Wisconsin); Francine
Schloegel-Moudry, Technical Director Bel/Kaukauna USA (Kentucky); Jacque
Daurelles, Director of Development Process Cheese, Fromageries/Bel; Mark
Johnson, Senior Scientist Dairy Research, Food Science Department, UW–Madison;
Eric Johnson and Ron Weiss, FRI; Marie-Helene Chassagne, Chief of Research
Application Group, Fromageries/Bel.
Front row: Jean-Paul
Gaulier, Engineering and Equipment Development, Fromageries/Bel; Robert
Gilbert, President Bel/Kaukauna USA; Kathleen Glass and Mike Pariza, FRI. |
|
|
Pillsbury |
Senior Research
and Technology staff members from Pillsbury, a Diageo Company, were
here to confer on current and pending research projects at FRI.
Back row, L to R:
Mike Pariza, FRI; Joe Shebuski, Senior Microbiologist, Pillsbury; Ron Weiss,
FRI; Hans F. Zoerb, Director Strategic Technology Development, Pillsbury;
David Domingues, Senior Research Scientist, Strategic Technology Development,
Pillsbury North America.
Front row: Ann Larson,
Kathleen Glass and Eric Johnson, all from FRI. |
What happened ...
Dioxin is a chemical contaminant which seems to appear periodically
in foods or the environment, attract a lot of coverage in the press, and
often involve political repercussions. The latest incident originated in
January of this year in a fat rendering plant in Belgium where about 8
L of used PCBs led to contamination of 1600 tons of feed (enough to feed
10 million chickens for a day).
Farmers noticed that hens were sick and their eggs were failing to hatch.
During the investigation in April, chickens and feed were found to contain
high levels of dioxin and related compounds (200–500 times background levels).
Amounts of these polychlorinated compounds were similar to the amounts
found in contaminated rice oil in the Yusho incident in Japan in 1968.
Since the contaminating fluid was a mixture of several compounds, concentrations
of contaminants were reported as TEQ or toxic equivalency (sum of the concentrations
of the compounds times their relative toxicity). Contaminant levels reported
for chickens and eggs intended for hatching ranged over 958, 741, 713,
266 TEQ parts per trillion (pg/g fat). Feed contained 781 parts per billion
(ng TEQ/g).
It was not until the end of May that these results were publicized by
the Belgian government, and chicken and egg products were withdrawn from
the market. Milk and pork may have been contaminated as well. The furor
resulting over the government's slow response forced the resignation of
the Belgian Prime Minister after his party lost in the national elections.
How important was it ...
The political and economic consequences to the government, the farmers,
feed industry and some food manufacturers and exporters have been significant,
if not downright disastrous. Health effects on the population will be more
difficult to assess. It has been estimated that background human daily
consumption of dioxin compounds in the U.S. ranges from 0.3 to 8 TEQ pg/kg
body weight with meat and dairy products accounting for 99% of that exposure.
Contaminant levels in Belgian chicken (average of 850 TEQ pg/g) were very
high as compared to dioxin levels reported in 1994 in U.S. poultry (0.03
pg/g) and beef (0.04-1.5 pg/g). During 1997 dioxin-contaminated chickens
containing 25 TEQ pg/g or more were found in supermarkets in the U.S.,
and the source was also traced to chicken feed. In this case, dioxin was
present in a clay added as an anti-caking agent to the feed. Although the
Belgian chickens were more highly contaminated, only a limited amount of
contaminated feed was produced while the American chickens may have been
consuming contaminated feed for several years. No acute effects on human
health have been reported in the U.S. and none has been reported so far
in Belgium.
Since we all consume minute amounts of these chlorinated compounds in
our food daily, apparently without ill effects, how much is too much? Numerous
cohorts of persons exposed to high levels of PCBs and dioxins in the past
have been followed to determine health effects. These groups include: (1)
persons exposed to dioxin after an explosion at a chemical plant in Seveso,
Italy, in 1976; (2) persons consuming contaminated rice oil in Japan (1968)
and Taiwan (1978-1979); (3) U.S. servicemen who spread defoliants in Vietnam
as part of Operation Ranch Hand; and (4) groups of industrial workers who
were occupationally exposed to these compounds. In addition, there have
been epidemiological studies of consumers of Great Lakes fish, Dutch children,
and, most recently, persons living in rural, cotton-growing areas of Kazakhstan.
What do all these studies tell us? One undisputed consequence of acute
exposure to high levels of PCBs, dioxins and related compounds is skin
lesions called chloracne, and also alterations in liver function. These
chlorinated compounds accumulate in body fat and are released slowly with
estimates of half-life residence in the body ranging from 7 to 15 years.
Do dioxins cause cancer or affect cardiac, neurological, hormonal, or
immune function? In animals, the answer is yes. The available epidemiological
data for humans is always incomplete; the answers are not so clear cut
and are subject to dispute. Nevertheless, IARC (International Agency for
Research on Cancer) concluded in 1997 that dioxin is a human carcinogen.
Data from Seveso suggest that the incidence of leukemia, non-Hodgkin's
lymphoma, and cardiovascular disease is higher in the most highly exposed
persons. Other data reported in 1999 on a group of 5132 chemical workers
in the U.S. who were exposed to dioxin indicated an increase in mortality
for all cancers combined, with excess cancer deaths occurring primarily
in highly exposed workers. Children who were in utero during the Yusho
and Yucheng rice oil contamination have been found to have an excess of
neurologic and respiratory disorders as well as other abnormalities at
birth. Some effects on cognitive development have also been noted in children
of persons consuming large amounts of Great Lakes fish.
Data on other exposed populations indicate that we should not expect
immediate adverse health effects from the contaminated chicken and eggs
in Belgium, but dioxins and related compounds are not innocuous, and the
increased body burden of these compounds may make the population more susceptible
to illness in the future.
—Ellin Doyle
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| FRI Newsletter, Fall 1999
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Dept. Food Microbiology & Toxicology
| UW–Madison |
Copyright © 1999
Food Research Institute
Last modified: 1 October
1999
Questions or Comments? e-mail
Barbara Cochrane