Smart Economy

40 years of federal nutrition research fatally flawed

University of South Carolina study shows flaws in NHANES
data

Four decades of nutrition research funded by the Centers for Disease Control
and Prevention (CDC) may be invalid because the method used to collect the data
was seriously flawed, according to a new study by the Arnold School of Public
Health at the University of South Carolina.

The study, led by Arnold School exercise scientist and epidemiologist Edward
Archer, has demonstrated significant limitations in the measurement protocols
used in the National Health and Nutrition Examination Survey (NHANES). The
findings, published in PLOS ONE (The Public Library of Science), reveal that a
majority of the nutrition data collected by the NHANES are not "physiologically
credible," Archer said.

These results suggest that without valid population-level data, speculations
regarding the role of energy intake in the rise in the prevalence of obesity are
without empirical support, he said.

The NHANES is the most comprehensive compilation of data on the health of
children and adults in the United States. The survey combines interviews of
self-reported food and beverage consumption over 24 hours and physical
examinations to assess the health and nutritional status of the US population.
Conducted by the CDC and the U.S. Department of Agriculture, the NHANES is the
primary source of data used by researchers studying the impact of nutrition and
diet on health.

The study examined data from 28,993 men and 34,369 women, 20 to 74 years old,
from NHANES I (1971 – 1974) through NHANES (2009 – 2010), and looked at the
caloric intake of the participants and their energy expenditure, predicted by
height, weight, age and sex. The results show that -- based on the self-reported
recall of food and beverages -- the vast majority of the NHANES data "are
physiologically implausible, and therefore invalid," Archer said.

In other words, the "calories in" reported by participants and the "calories
out," don't add up and it would be impossible to survive on most of the reported
energy intakes. This misreporting of energy intake varied among participants,
and was greatest in obese men and women who underreported their intake by an
average 25 percent and 41 percent (i.e., 716 and 856 Calories per-day
respectively).

"Throughout its history, the NHANES survey has failed to provide accurate
estimates of the habitual caloric consumption of the U.S. population," Archer
said. "Although improvements were made to the NHANES measurement protocol after
1980, there was little improvement to the validity of U.S. nutritional
surveillance."

These limitations "suggest that the ability to estimate population trends in
caloric intake and generate public policy relevant to diet-health relationships
is extremely limited," said Archer, who conducted the study with colleagues at
the Arnold School.

"The nation's major surveillance tool for studying the relationships between
nutrition and health is not valid. It is time to stop spending tens of millions
of health research dollars collecting invalid data and find more accurate
measures," he said.

 

###

 

To access the current study, please visit: http://dx.plos.org/10.1371/journal.pone.0076632.

 

 

 

New potential for nutrient-rich prairie fruits

Saskatchewan native fruits hold promise as an important
source of nutrients for local and global populations

Researchers working at the University of Saskatchewan have discovered new
potential in prairie fruits, in particular, buffaloberry, chokecherry and sea
buckthorn, according to a new study published today in the Canadian Journal
of Plant Science. Findings showed that these fruits were nutrient-rich and
that the potential food value is high. This is good news for fruit growers in
Saskatchewan as these results add further credence to support the development of
these fruits for commercial food markets.

"There is increasing interest in the commercial development of these fruits
since historically it has been thought they may provide nutritional and health
benefits," explained Dr. Rick Green, Vice President, Technology at POS
Bio-Sciences in Saskatoon, co-author of the study. "Our results provide evidence
that these fruits do, in fact, possess such nutritional benefits and contain
compounds of interest for their health and wellness attributes. Thus, our work
supports the commercial development of buffaloberry, chokecherry and sea
buckthorn berries."

According to the study:

• Buffaloberry was high in ascorbic acid, at a level that was greater than 4
  times that reported for oranges
• Chokecherry contained high levels of anthocyanin pigments (anti-oxidants)
  and can be considered a good source of these compounds with a concentration that
  was higher than the levels reported for fruits such as cranberry (anthocyanins
  purported health benefits include anti-inflammatory properties, and
  cardio-vascular benefits and potential anticarcinogenic properties)
• Sea buckthorn contained high levels of lipids for a fruit, though the level
  varies with location and variety.
• All of the fruits contained high levels of total dietary fibre

 

Potential uses for these native fruits are many. They can be used to produce
nutrient-rich ingredients for at-risk Northern Saskatchewan, Canadian and global
populations by blending fruits with Saskatchewan cereals and pulses. As
ingredients, these materials can be used to improve the food value of
traditionally prepared foods and as supplements for nutrient-poor populations.
Or, simply, they can be consumed directly as a healthy snack.

"Funding for a major project to investigate and further develop these
nutritive-rich ingredients is being sought from the recently established (2010)
Global Institute for Food Security (GIFS)," says co-author of the study Dr.
Nicholas Low, a Professor of Food Chemistry at the Department of Food and
Bioproduct Sciences, University of Saskatchewan. GIFS is a public–private
partnership that aims to address the growing global demands for safe and
nutritious foods. In addition, future research areas may focus on the
development of processed fruit products from these berries.

The article "Physicochemical composition of buffaloberry (Shepherdia
argentea), chokecherry (Prunus virginiana) and sea buckthorn
(Hippophae rhamnoides) fruit harvested in Saskatchewan, Canada" was
published online today in the Canadian Journal of Plant Science.

 

###

 

DOI:10.4141/CJPS2013-087

 

 

McGill discovery should save wheat farmers millions of dollars

Epigenetic factors identified as key to preventing loss of
wheat caused by rain and high humidity

		IMAGE: This image shows a sprouted spike of wheat.Click here for more information.

The global wheat industry sometimes loses as much as $1 billion a year  because prolonged rainfall and high humidity contribute to grains germinating before they are fully mature. The result is both a lower yield of wheat and grains of inferior quality. This phenomenon, known as pre-harvest sprouting or PHS, has such important economic repercussions for farmers around the world that scientists have been working on finding a solution to the problem for at least a couple of decades. Their focus has been on genetic factors, and on the interaction between genotypes and the environment as they have tried to breed wheat that is resistant to PHS, but with little success so far.

But now, findings by a McGill team suggest that the solution may lie not with genetics alone, but rather with a combination of genetic and epigenetic factors. The team, led by Prof. Jaswinder Singh of McGill's Department of Plant Science, has identified a key gene that acts as a switch to determine how a particular
plant will respond to high humidity and excess rainfall by either germinating early (PHS) or not. This switch is to be found in a key gene, ARGONAUTE4_9, in the "RNA dependent DNA Methylation" pathway (RdDM).

"The complex RdDM machinery is composed of several proteins that guide the genome in response to growth, developmental and stress signals. It's a bit like the plant's brain," says Singh. "Although in the past scientists have identified it as the pathway that regulates the way a variety of genes are expressed, until
now no one had made the link with PHS."

The McGill team made the discovery by using a variety of genomic and  molecular tools to identify specific ARGONAUTE4_-9 genes, and then compare the way that these genes are expressed in PHS resistant versus PHS susceptible varieties of wheat.

"This discovery is important for other cereals like barley as well as for wheat," said Surinder Singh, a Ph.D. student and one of the authors of this study, currently working in Professor Singh's laboratory. "This means that not only should we be able to avoid the ugly bread and sticky crumbs produced by PHS wheat in future, we should also end up with better beer. "

The research opens up a whole new area of exploration for scientists as they try to increase the yields of wheat and decrease losses due to excessively humid conditions. It should also save farmers and governments around the world significant amounts of money in the future.

 

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The study, "Polymorphic homoeolog of key gene of RdDM pathway, ARGONAUTE4_-9 class is associated with Pre-harvest Sprouting in wheat (Triticum aestivum L.)" was just published in the journal "PLOS ONE". To read the full article: http://dx.plos.org/10.1371/journal.pone.0077009

The research was funded by the Natural Sciences and Engineering Research Council of Canada (NSERC).

 

 

Better Tools for Saving Water and Keeping Peaches Healthy

By Dennis  O'Brien December 13, 2012 Peach growers in California may soon have better tools for saving water because of work by U.S. Department of Agriculture (USDA) scientists in Parlier, Calif Agricultural Research Service (ARS) scientist Dong Wang is evaluating whether infrared sensors and thermal technology can help peach growers decide precisely when to irrigate in California's San Joaquin Valley. ARS is USDA's principal intramural scientific research agency, and the research supports the USDA priority of promoting international food security. Irrigation is the primary source of water for agriculture in the valley  during the summer, and wells have been forced to reach deeper to bring up enough  water to meet increasing demands. Peaches also require much of their water from June through September, when temperatures and demands for water are at their highest. Wang and Jim Gartung, an ARS  agricultural engineer, installed 12 infrared temperature sensors in peach  orchards at the San Joaquin  Valley Agricultural Sciences Center in Parlier and gave trees one of four  irrigation treatments: applying furrow or subsurface drip irrigation, with or  without postharvest water stress. They also measured crop yields and assessed the quality of the fruit to  compare the output of trees grown under deficit irrigation with trees grown  under normal conditions. Deficit irrigation has been used to produce some  varieties of grapes and has been studied for its potential in fruit tree and row  crop production. But it has yet to be widely adopted, in part because growers  need better tools to strike a balance between saving water and keeping crops  viable and healthy, according to Wang. They used the sensors to measure temperatures in the tree canopies, and  calculated a "crop water stress index" based on the differences between tree  canopy temperatures and the surrounding air temperatures. Higher index numbers indicated more stressed trees. The researchers found that midday canopy-to-air temperature differences in  trees that were water-stressed postharvest were in the 10- to 15-degree  Fahrenheit range, consistently higher than the 3- to 4-degree Fahrenheit range  in the trees that were not water-stressed. For comparison purposes, the researchers placed leaves from stressed and non-stressed trees in a pressure chamber and measured the pressure required to squeeze water out of them. When the trees are water-stressed, it takes more pressure to squeeze moisture from them. The results, published in Agricultural Water Management, show that the pressure chamber results were  consistent with data collected by the infrared sensors, which means the sensors may be an effective tool for managing water use in peach orchards. Read more about this research in the November/December 2012 issue of Agricultural Research magazine.

Chinese scientists announce GM cows to produce 'human milk'

  (hat tip to Steve Kutz)

SCIENTISTS PREDICT STRONG THIRST FOR 'HUMAN MILK'

SOURCE: China Daily, China

AUTHOR:

URL: http://english.peopledaily.com.cn/90001/90776/90882/7326680.html

DATE: 22.03.2011

SUMMARY: "Genetically modified dairy products that are similar to human milk will appear on the Chinese market in two years, an expert in biotechnology has predicted. Li Ning, a scientist from the Chinese Academy of Engineering and director of the State Key Laboratories for AgroBiotechnology at China Agricultural University, said [...] Chinese scientists have successfully created a herd of more than 200 cows that is capable of producing milk that contains the characteristics of human milk."

_______

SCIENTISTS PREDICT STRONG THIRST FOR 'HUMAN MILK'

Genetically modified (GM) dairy products that are similar to human milk will appear on the Chinese market in two years, an expert in biotechnology has predicted.

Li Ning, a scientist from the Chinese Academy of Engineering and director of the State Key Laboratories for AgroBiotechnology at China Agricultural University, said progress in the field is well under way.

Li said Chinese scientists have successfully created a herd of more than 200 cows that is capable of producing milk that contains the characteristics of human milk.

He said the technology is at the cutting edge worldwide and will ensure "healthy protein contained in human milk is affordable for ordinary consumers".

Photos depicting the GM cows were on display at an exhibition, held between March 7 and 14 in Beijing, that showcased China's major technological achievements during the period of the 11th Five-Year Plan (2006-2010).

"In ancient China, only the emperor and the empress could drink human milk throughout their lives, which was believed to be the height of opulence," Li said. "Why not make that kind of milk more available for ordinary people?"

Human milk contains two kinds of nutrition that can help improve the immune systems and the central nervous systems of children. The components are not available in milk produced by goats or cows.

Li said the scientific world had not previously found a way to mass-produce those ingredients. The GM milk will be as safe to drink as that of the ordinary cows, he added.

The Ministry of Agriculture issued bio-safety examination certificates for the GM herd in March 2010, giving the scientific team a 22-month period during which the technology can be tested in laboratories.

The ministry will then evaluate the results of the tests before deciding whether to allow the milk to be sold.

"The milk tastes stronger than normal milk," Li said. "Within 10 years, people will be able to pick up these human-milk-like products at the supermarket."

Xue Dayuan, chief expert with the Ministry of Environmental Protection, said the government will carry out a series of tests on the transferred gene and the method of transplanting it before the genetically modified cows and their milk are declared safe.

There has been a good deal of opposition to GM technology in the United States and Canada, according to Fang Lifeng, a campaigner for Greenpeace China's food and agriculture project.

Xinhua contributed to this story.

Can the world feed 10 billion people?

Feeding 10 billion a mid-century challenge

By Paul Hanley, Postmedia News February 24, 2011

The world's population will soon hit seven billion, more than double the number when I was born. When my grandchildren reach my current age in the 2060s the population will likely be closer to 10 billion. That's like adding two more Chinas - or what was the entire human population in 1960 - in just 50 years.

As we consider how to make the world work for 10 billion, one of the key questions is, "Where will the food come from?" The answer could have implications for Saskatchewan.

Average cereal grain production is a general statistic, but provides a reasonable picture of relative food productivity in the world. The average cereal yield is 2,790 kilograms/hectare, enough to provide 7.6 kg of grain per day for a year or about 2,500 calories for 9.2 people daily. (There are about 2, 500 food calories in .83 kg of a cereal like wheat.)

Out of 172 countries, 73 produce more than the world average, with some, such as Belgium, tripling it. The other 99 produce below the world average; sometimes, as in the case of Botswana, as little as a tenth.

Botswana is a desert nation and should not be compared to, say, neighbouring South Africa, which with its more favourable conditions has yields averaging 3, 330 kg/ha. South Africa is better compared to its neighbour, Zimbabwe, where average yields are one quarter of South Africa. Zimbabwe once bore the title "the breadbasket of Africa," but production has plummeted due to its disastrous political regime. Mainly because of socio-political factors, a hectare of farmland in South Africa could support about 11 people, compared to just 2.3 for Zimbabwe.

Achieving a more unified society with good governance and freedom for farmers and markets has a profound influence on productivity and the ability to feed larger populations.

Ukraine provides a good example of this. Ukraine has 32 million ha of arable land, the eighth largest agricultural land base in the world, plus some of the best farming conditions. Yet current grain yields average 2,630 kg/ha, below the world average. Compare that to a geographically equivalent area like Germany where yields average 6,660 kg/ha. If Ukraine's farms yielded like Germany's, Ukraine could produce as much as 218 million tonnes of grain annually on its arable land, enough to feed 720 million people.

Russia's potential is even greater due to its vast size with 122 million ha of arable land that produces an average of 1,852 kg of cereal per ha. If Russia could produce the same average yield as Canada (3,031kg/ha), it could produce 364 million tonnes of grain, sufficient to feed 1.2 billion people. If it could produce closer to German levels of production, it could produce 800 million tonnes of grain, enough for 2.8 billion people.

So under a more favourable socio-economic climate, including good governance, Russian and Ukrainian agriculture could theoretically supply food for almost all the population increase expected by 2060.

If all the world's arable area was planted with cereals that yielded the global average of 2.8 tonnes/ha, total world grain production could be 3.9 billion tonnes, enough to provide food for 13 billion people, if eaten directly rather than fed to animals. On top of arable land, there are about 140 million ha in permanent crops and 3.4 billion ha in pastures -plus aquaculture and ocean and inland fisheries -to provide other food sources.

Looking at global statistics, we can see a majority of countries are producing food at well below the world average. Often, low production has nothing to do with the land's productive capacity. It's about social, economic and political realities -even physical constraints like poor soil quality are consequences of social, economic and political realities.

Having sufficient food for 10 billion is doable, but it will depend on adopting best governance and socio-economic practices. Equally important, and perhaps even more difficult, will be ensuring that food-producing systems are environmentally sustainable. More on that in a future column.

Saskatoon StarPhoenix

================== 

Walter Derzko

 

When will the recession end? Part 128 Texas Drought adds to US misery-where's the beef?

LUBBOCK, Texas (AP) — There's no green in any of Central Texas rancher Gerry Shudde's pastures. Again.

Dry conditions are expected to worsen in the next six weeks and persist through at least February, weather officials said. The culprit is La Nina, a weather pattern that typically means less than normal rainfall and above normal temperatures.

"The screaming message will be the drier part, more so than the warmer," said Victor Murphy, a National Weather Service meteorologist. "Things are pretty much bad and going to get worse."

This month there has been no rainfall in Texas west of a line from the Dallas-Fort Worth area to Corpus Christi and none is expected in the next week.

In October and November, rainfall in far South Texas and far West Texas was only as much as 10 percent of normal. The Panhandle got a more reasonable 70 percent to 90 percent of normal. Most of the rest of the state is between 10 percent and 30 percent of normal.

The current U.S. Drought Monitor map, released last week, shows that 85 percent of Texas is between abnormally dry or worse, with extreme drought covering 3.8 percent of the state.

[..] 

See Texas agriculture braces for yet another drought

http://www.bloomberg.com/news/2010-12-15/texas-agriculture-braces-for-yet-another-drought.html

Scientists suggest that cancer is purely man-made

 

 

Cancer is a modern, man-made disease caused by environmental factors such as pollution and diet, a study by University of Manchester scientists has strongly suggested. 

The study of remains and literature from ancient Egypt and Greece and earlier periods – carried out at Manchester’s KNH Centre for Biomedical Egyptology and published in Nature Reviews Cancer – includes the first histological diagnosis of cancer in an Egyptian mummy.

Finding only one case of the disease in the investigation of hundreds of Egyptian mummies, with few references to cancer in literary evidence, proves that cancer was extremely rare in antiquity. The disease rate has risen massively since the Industrial Revolution, in particular childhood cancer – proving that the rise is not simply due to people living longer.

Professor Rosalie David, at the Faculty of Life Sciences, said: “In industrialised societies, cancer is second only to cardiovascular disease as a cause of death. But in ancient times, it was extremely rare. There is nothing in the natural environment that can cause cancer. So it has to be a man-made disease, down to pollution and changes to our diet and lifestyle.”

She added: “The important thing about our study is that it gives a historical perspective to this disease. We can make very clear statements on the cancer rates in societies because we have a full overview. We have looked at millennia, not one hundred years, and have masses of data.”

The data includes the first ever histological diagnosis of cancer in an Egyptian mummy by Professor Michael Zimmerman, a visiting Professor at the KNH Centre, who is based at the Villanova University in the US. He diagnosed rectal cancer in an unnamed mummy, an ‘ordinary’ person who had lived in the Dakhleh Oasis during the Ptolemaic period (200-400 CE).

Professor Zimmerman said: “In an ancient society lacking surgical intervention, evidence of cancer should remain in all cases. The virtual absence of malignancies in mummies must be interpreted as indicating their rarity in antiquity, indicating that cancer causing factors are limited to societies affected by modern industrialization”.

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The team studied both mummified remains and literary evidence for ancient Egypt but only literary evidence for ancient Greece as there are no remains for this period, as well as medical studies of human and animal remains from earlier periods, going back to the age of the dinosaurs.

Evidence of cancer in animal fossils, non-human primates and early humans is scarce – a few dozen, mostly disputed, examples in animal fossils, although a metastatic cancer of unknown primary origin has been reported in an Edmontosaurus fossil while another study lists a number of possible neoplasms in fossil remains. Various malignancies have been reported in non-human primates but do not include many of the cancers most commonly identified in modern adult humans.

It has been suggested that the short life span of individuals in antiquity precluded the development of cancer. Although this statistical construct is true, individuals in ancient Egypt and Greece did live long enough to develop such diseases as atherosclerosis, Paget's disease of bone, and osteoporosis, and, in modern populations, bone tumours primarily affect the young.

Another explanation for the lack of tumours in ancient remains is that tumours might not be well preserved. Dr. Zimmerman has performed experimental studies indicating that mummification preserves the features of malignancy and that tumours should actually be better preserved than normal tissues. In spite of this finding, hundreds of mummies from all areas of the world have been examined and there are still only two publications showing microscopic confirmation of cancer. Radiological surveys of mummies from the Cairo Museum and museums in Europe have also failed to reveal evidence of cancer.

As the team moved through the ages, it was not until the 17th century that they found descriptions of operations for breast and other cancers and the first reports in scientific literature of distinctive tumours have only occurred in the past 200 years, such as scrotal cancer in chimney sweeps in 1775, nasal cancer in snuff users in 1761 and Hodgkin’s disease in 1832.

Professor David – who was invited to present her paper to UK Cancer Czar Professor Mike Richards and other oncologists at this year’s UK Association of Cancer Registries and National Cancer Intelligence Network conference – said: “Where there are cases of cancer in ancient Egyptian remains, we are not sure what caused them. They did heat their homes with fires, which gave off smoke, and temples burned incense, but sometimes illnesses are just thrown up.”

She added: “The ancient Egyptian data offers both physical and literary evidence, giving a unique opportunity to look at the diseases they had and the treatments they tried. They were the fathers of pharmacology so some treatments did work

“They were very inventive and some treatments thought of as magical were genuine therapeutic remedies. For example, celery was used to treat rheumatism back then and is being investigated today. Their surgery and the binding of fractures were excellent because they knew their anatomy: there was no taboo on working with human bodies because of mummification. They were very hands on and it gave them a different mindset to working with bodies than the Greeks, who had to come to Alexandria to study medicine.”

She concluded: “Yet again extensive ancient Egyptian data, along with other data from across the millennia, has given modern society a clear message – cancer is man-made and something that we can and should address.”

More information: A copy of the paper ‘Cancer: an old disease, a new disease or something in between?’ is available at http://www.nature. … nrc2914.html

Provided by University of Manchester

http://www.physorg.com/news/2010-10-scientists-cancer-purely-man-made.html

Cell phones and mobile phone towers kill honey bees

The Telegraph newspaper in the Uk reports on research that was published last Aug 2009

Mobile phone towers a threat to honey bees: study (August 31, 2009)

The electromagnetic waves emitted by mobile phone towers and cellphones can pose a threat to honey bees, a study published in India has concluded.

An experiment conducted in the southern Indian state of Kerala found that a sudden fall in the bee population was caused by towers installed across the state by cellphone companies to increase their network.

The electromagnetic waves emitted by the towers crippled the "navigational skills" of the worker bees that go out to collect nectar from flowers to sustain bee colonies, said Dr. Sainuddin Pattazhy, who conducted the study, the Press Trust of India news agency reported.

He found that when a cell phone was kept near a beehive, the worker bees were unable to return, leaving the hives with only the queens and eggs and resulting in the collapse of the colony within ten days.

The Telegraph writes:

They set up a controlled experiment in Punjab earlier this year comparing the behaviour and productivity of bees in two hives – one fitted with two mobile telephones which were powered on for two fifteen minute sessions per day for three months. The other had dummy models installed.

After three months the researchers recorded a dramatic decline in the size of the hive fitted with the mobile phone, a significant reduction in the number of eggs laid by the queen bee. The bees also stopped producing honey.

The queen bee in the "mobile" hive produced fewer than half of those created by her counterpart in the normal hive.

They also found a dramatic decline in the number of worker bees returning to the hive after collecting pollen. Because of this the amount of nectar produced in the hive also shrank.

Ved Prakash Sharma and Neelima Kumar, the authors of the report in the journal Current Science, wrote: "Increase in the usage of electronic gadgets has led to electropollution of the environment. Honeybee behaviour and biology has been affected by electrosmog since these insects have magnetite in their bodies which helps them in navigation.

"There are reports of sudden disappearance of bee populations from honeybee colonies. The reason is still not clear. We have compared the performance of honeybees in cellphone radiation exposed and unexposed colonies.

So will society have to make a choice: wireless chatting & texting or food on your plate from agriculture?

Walter Derzko 

Risk of E.coli O157:H7 crop contamination from California wildlife everpresent but low

E. COLI 0157:H7 PRESENT BUT NOT COMMON IN WILDLIFE OF NATION'S SALAD BOWL

 

The disease-causing bacterium E. coli O157:H7 is present but rare in some wildlife species of California's agriculturally rich Central Coast region, an area often referred to as the nation's "salad bowl,"

reports a team or researchers led by a UC Davis scientist.

 

 

The researchers, who are nearing completion of a massive field study to help identify potential sources of E. coli O157:H7 near Central Coast farms, presented their findings today during the annual meeting of the American Society for Microbiology in San Diego. They reported finding occasional E. coli O157:H7 infections in fecal samples of wildlife species common to the area, including cowbirds, coyotes, crows, mice and feral pigs.

 

Based on their findings, the researchers recommend that farmers in this region continue to follow "good agricultural practices," a set of accepted, on-farm procedures designed to protect crops from contamination during production and harvest (<http://ucgaps.ucdavis.edu/>).

 

The study was spurred by a 2006 nationwide E. coli O157:H7 outbreak linked to fresh, bagged spinach grown in California; the outbreak resulted in 205 reported illnesses and three deaths.

"The study helps us better understand the possible risk of crop contamination from wildlife and allows us to compare that to the risk of contamination from other possible sources such as livestock and irrigation water," said lead study author Michele Jay-Russell, a veterinarian at UC Davis' Western Institute for Food Safety and Security.

"We are sharing this data with the produce industry, regulators, and conservation groups to help improve prevention strategies that protect public health and preserve native wildlife populations and their habitats," she said.

E. coli O157:H7 poses a serious human health threat, commonly causing abdominal cramps and diarrhea, sometimes bloody. Severe infections may be require hospitalization and result in kidney damage and even death. People most at risk for serious complications include young children, the elderly and those with compromised immune systems.

From 2008 through 2009, the team collected and tested 1,133 fecal samples from wild birds and mammals on 38 private properties in Monterey, San Benito and San Luis Obispo counties in California. All three counties are home to farms that grow fresh spinach, lettuce and other produce.

Laboratory tests revealed that E. coli O157:H7 was present in samples from two cowbirds, two coyotes, five crows, one deer mouse and 10 feral pigs. Samples from deer, opossums, raccoons, skunks, ground squirrels and other bird and mouse species all tested negative for the bacterium.

Robert Mandrell, principle investigator and research leader from the U.S. Department of Agriculture's Agricultural Research Service, said that the discovery of a low level of E. coli O157: H7 among Central Coast wildlife was somewhat surprising.

"The fact that we have identified two bird species with an incidence of E. coli O157:H7 of more than 3 percent, feral swine with about a 4 percent incidence and several coyotes and rodents that tested positive for O157:H7 suggests there are at least several sources of pathogen movement in this region," Mandrell said.

"We have no evidence that the concentration of the pathogen was high in the feces of the animals that tested positive, so the significance of wildlife as a source of direct contamination associated with outbreaks remains unclear," he said.

Mandrell said the researchers are comparing the genetic makeup of the E. coli O157: H7 strains found in wildlife to that of strains isolated from other sources including cattle, soil and water. They hope these comparisons will help them to better assess the movement of the bacteria in this agriculturally important region.

Following up on these findings, the study team is evaluating other potential wildlife sources of E. coli O157:H7, including amphibians and reptiles, and is conducting focused research to refine best practices that promote appropriate management to protect both food safety and the environment.

The collaborative research team included microbiologists and epidemiologists from the Agricultural Research Service and the Western Regional Research Center and Wildlife Services, both of the U.S. Department of Agriculture; the Western Institute for Food Safety and Security and the Western Center for Food Safety, both at UC Davis; and the University of California Cooperative Extension.

The study was funded by the U.S. Department of Agriculture and the U.S. Food and Drug Administration.

 

Source: University of California, Davis, May 24, 2010

 

Walter Derzko, The Opportunity Clinic, Smart Economy, Toronto