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Research helps ensure safety of leafy greens

Four years ago, a multi-state outbreak of E. coli O157:H7 in fresh baby spinach gripped the nation. Nearly 200 people in 26 states came down with the disease. Two elderly women and a 2-year-old boy died.

The outbreak was also devastating for the industry. The contaminated spinach was traced back to Central California, where growers produce 80 percent of the nation’s leafy greens. Scientists, farmers and regulators worked together to restore public confidence in products that are widely considered part of a healthy diet.  Regulators and farmers created the California Leafy Green Marketing Agreement to establish a culture of food safety on leafy greens farms and researchers worked to close gaps in the body of scientific knowledge about the sources of E. coli O157:H7 in the region.

In 2006, UC and USDA researchers were already designing a four-year study of the possible sources of E. coli O157:H7 near Central California fresh produce fields when the high-profile spinach outbreak occurred. This month, data collection from rangeland and farmland, steams and irrigation canals comes to a close. The team of scientists is now analyzing the data to reach conclusions that will help prevent future food contamination.

Preliminary results reflect a diversity of E. coli O157:H7 carriers near Central Coast farms, according to Edward (Rob) Atwill, a UC Davis School of Veterinary Medicine specialist in waterborne infectious diseases and co-principal investigator of the study. Early on, free-ranging feral swine were implicated as carriers of the deadly bacteria, but it wasn’t known whether there were other sources in the environment. The researchers collected 1,233 samples of wild and feral animal scat from 38 Central Coast cattle ranches and leafy greens farms that were adjacent to riparian, annual grassland and oak woodland habitat. Eighteen of the samples were found to contain E. coli O157:H7.

The scientists found the bacteria in

  • 3 of 60 brown-headed cowbirds
  • 5 of 93 American crows
  • 2 of 95 coyotes
  • 1 of 72 deer mice
  • 10 of 200 feral swine

E. coli O157:H7 was not found in scat samples from deer, opossums, raccoons, skunks, ground squirrels, or other bird and mouse species.

“Our goal over the next nine months is to finish analyzing this very large and comprehensive dataset and to identify various good agricultural practices that reduce the risk of foodborne pathogens for the produce industry,” Atwill said.

Research helps prevent contamination of fresh leafy greens.
Research helps prevent contamination of fresh leafy greens.

Posted on Wednesday, October 27, 2010 at 7:04 AM

What's shakin'

Harvest time in California is almost a year-round affair in one area or another: winter lettuce and spinach in Salinas, early spring strawberries along the South Coast, summer squashes, herbs, and tomatoes galore, hays and grains as long as the dry season lasts, and countless other food and fiber crops through the year.

Like grapes, walnuts, apples and olives, the almonds get their turn in autumn. On the right day, you can watch as a Rube Goldberg-like machine rolls through a local nut orchard, grabbing hold of tree trunks one by one and shaking them so hard it'll rattle your bones, but just hard enough to knock loose practically every nut on the tree without damaging its trunk. A sweeper follows next, gathering up nuts in their rough hulls from the clean orchard floor, blowing them clean of debris, and dumping them into harvest bins. Simple as that. But 60 or 70 years ago this work was all done by hand, and the harvest that's now completed in a day could take a week or more.

First the farmers would clean the orchard floor and spread a big canvas sheet under a tree, wide enough to catch anything that could fall from its canopy. One or more members of the harvest crew then took up long, slender poles and knocked loose the harvest-ready nuts, still in their hulls. Nuts rained dusty onto the workers' wide-brimmed hats and the wide-spread sheet. A skilled harvester could work the long, willowy pole with a fly fisherman's skill to strike the last few stick-tight nuts, one by one, and down they'd fall. Each nut meant another ounce or so, which added up to pounds and eventually dollars from the buyer or co-op. Then as now, you don't do this sort of thing just for your health.

Nuts from the sheet were raked and shoveled onto a sled and dragged out of the orchard. While the harvest crew set to work on the next tree, others would pick debris out of the sled, scoop the cleaned nuts into big burlap sacks, stitch them shut, and load them onto a wagon for a trip to the railroad and on to market.

Old times and new. This year, California's largest almond-growing cooperative, Blue Diamond Growers, celebrates its 100th anniversary. You can learn more about the crop's history in California at a special centennial website.

A nut tree shaker.
A nut tree shaker.

Posted on Monday, October 25, 2010 at 7:19 AM

A new era begins in food and beverage science

A new winery, brewery and food-processing complex began operations this fall at UC Davis. Part of the Robert Mondavi Institute for Wine and Food Science, the technologically sophisticated facilities will be used to teach students, conduct research, and solve practical problems related to foods, beverages and health.

The south wing of the new complex is home to the August A. Busch III Brewing and Food Science Laboratory, which includes the brewery, general foods-processing plant and milk-processing laboratory. The complex’s north wing houses a new teaching-and-research winery. The complex is adjacent to a 12-acre teaching-and-research vineyard and across a courtyard from the departments of Food Science and Technology, and Viticulture and Enology.

The new $20 million, 34,000-square-foot complex, funded entirely by private donations, will be the first winery, brewery and/or food-processing facility to earn LEED Platinum certification, the highest environmental rating awarded by the U.S. Green Building Council. (LEED stands for Leadership in Energy and Environmental Design.)

Features include onsite solar power generation and a system for capturing rainwater and conserving processing water. Stored rainwater will be used for landscaping and toilets.

The winery (right) will capture carbon dioxide, a natural byproduct of fermentation, thus reducing the building’s energy requirements for air quality and temperature control.

Other features include maximum use of natural light, food-processing equipment that minimizes energy and water requirements, use of recycled glass in flooring, interior paneling recycled from a 1928 wooden aqueduct, and use of sustainably certified lumber.

The new brewery will showcase the latest in brewing technology, as well as a sophisticated laboratory for conducting research and training students. It also provides commercial brewers and suppliers with a small-scale facility to test new recipes or processes.

The general foods- and milk-processing laboratories have been built to meet state and federal food- and dairy-grade standards. Products processed there will be used in sensory and nutritional evaluations.

Research in the food-processing pilot plant will examine alternative food-processing methods and their nutritional effects, nutritional quality and shelf life of fresh-cut fruits and vegetables, nutritional enhancements from food-processing “waste” products, and improved food formulations.

The milk-processing laboratory will support research on separation of milk components into functional ingredients, processing of milk modified by different feed rations, and processing of milk from cows bred for specific characteristics.

Dozens of private donors helped make the complex a reality, including a $5 million contribution from the late winemaker, Robert Mondavi, and a $5 million pledge by the Anheuser-Busch Foundation.

Other major donations were made by Ronald and Diane Miller and by a group of winery partners led by Jess Jackson and Barbara Banke of Kendall-Jackson Wines, and Jerry Lohr of J. Lohr Vineyards & Wines. The Department of Viticulture and Enology’s Board of Visitors and Fellows also made significant contributions.

California tomato processors and growers contributed more than $2.5 million to the food-processing pilot plant. Morning Star Packing Company provided a lead gift of $1 million for the food-processing plant. Hilmar Cheese Company also stepped up with a $250,000 pledge.

In all, more than 150 individuals, alumni, corporations and foundations contributed funds for the new winery, brewery and food-processing complex.

(Thanks to Patricia Bailey, UC Davis News Service, who provided content for this post.)

Learn more at

Posted on Friday, October 22, 2010 at 6:54 AM

Halloween kicks off the season of sweets

The season of sweets begins for many children at the end of October with a large bag of trick-or-treat candy, and then continues in earnest with the traditional candy-giving holidays of Christmas, Valentine’s Day and Easter. Children's access to so much candy has many parents asking how much is too much.

Candy occupies a very tiny slice of MyPyramid, the USDA’s dietary guideline. MyPyramid places candy in a category called “extras.” For children aged 2 to 8 years old, it recommends no more than 170 calories per day of “extras” – which would be two-thirds of a Snickers bar, one pack of Starburst or 17 Whoppers.

Michele Fisch, program representative for the Placer County UC Cooperative Extension Nutrition BEST program, gathered suggestions that will help parents enforce limits on their children’s candy consumption.

  • Set a specific amount for each week and stick to it. Inform children of the limit and allow them to help decide when to indulge.

  • Out of sight, out of mind. After a night of trick-or-treating, allow for a few pieces of candy and then put the rest out of sight. Most children will forget it is around within a few days.

  • Help other families with the battle by offering something other than sweets for children. Small cans of play dough, boxes of crayons, and other toys can now be purchased easily where you shop for candy.

  • Keep sweet but healthy alternatives around the house for snacks.  Fresh fruit and yogurt are good choices.

  • It's never a good idea to reward children with sweets. Instead offer love and praise for a job well done.

16 M&Ms fulfill a child's limit of
16 M&Ms fulfill a child's limit of "extras."

Posted on Wednesday, October 20, 2010 at 7:48 AM

Dietary intake and patterns can change with age

Senior citizens may have trouble eating and accessing healthy foods due to physiological changes in their gastrointestinal systems, physical problems that limit the ability to shop for and prepare food, or limited incomes that prevent the purchase of adequate and nutritious meals, according to Mary Blackburn, the nutrition, family and consumer sciences advisor for UC Cooperative Extension in Alameda County.

Blackburn and her colleagues shared these observations in an article in the current issue of California Agriculture journal titled "Research is needed
to assess the unique nutrition and wellness needs of aging Californians."

“Poor appetite or lack of appetite may plague elders who live alone, are lonely or do not feel like cooking, while the lack of funds to buy food affects food accessibility, availability, quality and variety,” Blackburn wrote. “Low literacy may mean that some elders are unable to read or comprehend nutrition and wellness information. Poor vision can make it difficult to read nutrition labels and to control intakes of dietary sodium, sugar and fat, as well as avoid foods to which one is sensitive."

Blackburn cites nutrition recommendations for those over age 50, from the U.S. Department of Health and Human Services. They include:

  • Achieve adequate nutrition within calorie needs from nutrient-dense foods, and limit saturated and trans fats, cholesterol, added sugars, salt and alcohol.
  • Maintain body weight in a healthy range, and lose weight slowly.

  • Participate in 30 minutes of moderate physical activities daily to reduce the functional decline of aging.

  • Keep fat consumption between 20 percent and 35 percent of total caloric intake.

  • Choose fiber-rich carbohydrates such as fruits, vegetables and whole grains.

  • Limit sugar, caloric sweeteners and starch to prevent dental problems.

  • Use no more than 2,300 milligrams sodium (1 teaspoon table salt) per day, and eat potassium-rich fruits and vegetables to reach 4,700 milligrams per day total salt.

  • Middle-aged and older, hypertensive and black adults should reduce salt intake to 1,500 milligrams per day.

  • Limit daily alcoholic beverages to two for men and one for women.

  • Do not consume alcohol if it can interact with medications, or when medical conditions prohibit its use.

  • To prevent food-borne illness, do not eat unpasteurized, improperly cooked or uncooked foods.

Six articles in the October-December 2010 issue of the University of California’s California Agriculture journal explore the impact of aging on a range of health, lifestyle and policy issues, including nutrition and wellness, memory, stress, quality of life, health literacy and caregiving needs. The entire special issue on aging, “The Golden State goes gray: What aging will mean for California,” can be viewed and downloaded at

California Agriculture is the University of California’s peer-reviewed journal of research in agricultural, human and natural resources. For a free subscription, go to:, or write to

Posted on Monday, October 18, 2010 at 1:02 PM
  • Author: Janet Byron

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