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UC Food Safety

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How authentic is your pomegranate juice?

You pick up a bottle of pomegranate juice because you’ve learned that, although it costs more than most juices, it is replete with antioxidants that bring health benefits. But wait: Is the juice you’ve purchased really pomegranate juice? Or is the product label you have carefully read promising more than it delivers?

UC Riverside chemistry professor Cynthia Larive is determined to find out. She is playing detective by applying chemical tests to juice products sold as pomegranate juice or pomegranate juice blends in order to authenticate their contents.

“We are measuring levels of unique compounds in pomegranate juice and are able to use this ‘molecular fingerprint’ to discriminate against adulterated juice products,” says Larive, whose research on pomegranate juice is being funded by a nearly $50,000 one-year grant from Pom Wonderful, a company that grows and markets pomegranates and pomegranate-based products.

In the lab, Larive and her graduate student Daniel Orr are measuring levels of biochemicals in juices, such as amino acids, organic acids, sugars, pomegranate pigment compounds and health-producing antioxidant molecules that are unique to pomegranate juice.

“We have received a collection of pomegranate samples from around the world, as well as commercial juices such as beet, grape, apple and pear – to name just a few,” Larive says. “We’re looking at whether or not our molecular fingerprint method can be used to identify products claiming to contain pomegranate juice when they don’t, and products claiming to be pomegranate juice when they are not.”

Larive plans to publish her results soon in a peer-reviewed journal.  For the complete news release about the research, see the UC Riverside media website.

Posted on Wednesday, December 1, 2010 at 9:38 AM

Putting pesticide residues in perspective

A child could eat more than 11,000 servings of lettuce in one day without any ill effect from pesticide residues, even if the lettuce has the highest pesticide residue recorded for lettuce by the USDA. That is just one fact shared on a new pesticide residue calculator produced by the Alliance for Food and Farming, a non-profit organization that provides a voice for farmers to communicate their commitment to food safety and care for the land.

UC Riverside toxicologist Robert Krieger analyzed data from USDA's Pesticide Data Program to create the online tool. The calculator allows users to select a consumer (man, woman, teen or child) and then choose from 14 types of fruits and vegetables. The tool then calculates the number of servings that consumer could eat in a day and still not see any effect from pesticide residues.

For example, a woman could eat 836 servings of cherries, 219 servings of blueberries, or 2,332 servings of kale in one day without any effect even if the produce had the highest pesticide residue recorded by USDA.

Earlier this year, the Environmental Working Group released a shopper's guide that lists produce it calls the "dirty dozen" and the "clean 15." The working group suggested that the shopper's guide could help consumers determine which fruits and vegetables have the most pesticide residues and so are the most important to buy organic.

However, an expert panel convened by the Alliance for Food and Farming determined such lists are misleading to consumers, a detriment to public health because they discourage produce consumption, and they lack scientific evidence that the pesticide levels found on fruits and vegetables pose any risk. UC Davis nutrition professor Carl Keen was a member of the expert panel.

"There is vast and overwhelming scientific evidence which shows the health benefits of eating a diet rich in fruits and vegetables,” Keen said. "Just about everyone agrees that consumers should be eating more fruits and vegetables for good health."

Keen said that even some of the groups that publish these so-called 'dirty' lists tell consumers that the benefits of a diet rich in fruits and vegetables outweigh any small risks from pesticide residues.

"So please enjoy the abundance of choices and eat more fruits and vegetables," Keen said.

Posted on Monday, November 29, 2010 at 7:29 AM

Holiday food safety

Why is there a turkey in the garage?!  If you’ve ever found yourself asking any variant of this question, trust us - you’re going to want to read on.

As the holiday season approaches, we begin to think about spending time with our families, enjoying one another’s company over the many feasts that accompany special days. While we may set aside mindful eating during the holiday season, we should not set aside food safety.

In many families, once the holiday meal is served it may sit on the table for 2-3 hours while people come and go, “picking” from the various serving dishes. The most creative food safety flub goes to a family member who thaws her holiday turkey in her garage. Her justification of this practice?  “I haven’t hurt anyone yet!” 

With respect for time-honored traditions, might we suggest that this festive time of giving and sharing SHOULD NOT include sharing foodborne illness by forgetting food safety measures? In many California counties, we may still have some heat lingering late into the November month. How much harm can the garage thawing method, or “GTM” if you will, really have? After all, we will be cooking it appropriately right? Wrong!

A few turkey thawing tips:

  • If thawing your turkey in the refrigerator; plan for 24 hours per 4-5 pounds of turkey.

  • Place the turkey into a container to avoid contaminating other foods.

  • If thawing your turkey in cold water; plan for 30 minutes per 1 pound of turkey. Remember to change the water every 30 minutes.

  • If thawing your turkey in the microwave; follow the manufacturer guidelines.

  • A turkey thawed in cold water or in the microwave must be cooked immediately.

(Photo: USDA)

Cooking your turkey properly ensures that all harmful bacteria have been destroyed.

Cooking time ranges from 2¾ hours to 5¼ hours depending on size and whether the turkey is stuffed. To check the temperature of a properly cooked turkey, one should insert the thermometer into the innermost part of the thigh and wing as well as the thickest part of the breast; proper temperature should read 165 degrees. Once all parts have reached this minimum temperature, it is safe to eat, even if parts should remain pink. Stuffing should read 165 degrees when properly cooked as well.

Here are a few tips to keep your foods safe when storing leftovers:

  • Cut turkey or other meats into smaller pieces. Store stuffing separately.
  • Divide large quantities of food items into smaller portions before storing.
  • Store different food items separately.
  • Turkey that is stored in the refrigerator can be held for 3-4 days; reheat to 165 degrees.
  • Frozen turkey can be stored for 2-6 months; reheat to 165 degrees.

Enjoy your holiday feast and be sure to keep your foods safe!

These tips and more can be found at

Blog contributors: Connie Schneider, Ph.D., R.D., Laurin Herrera, CSUF Dietetic Intern, & Shelby MacNab, Nutrition Program Manager

Posted on Wednesday, November 24, 2010 at 7:45 AM
  • Author: Shelby MacNab

'Extra virgin' olive oil: What is it and why does it matter?

Dipping fresh bread into olive oil has become a popular alternative to coating it with butter. Olive oil consists of 85 percent unsaturated fats, and when substituted for saturated fat in the diet can promote ”good” cholesterol (high density lipoprotein or HDL), reducing risk of coronary artery disease.

Some olive oils are more beneficial than others. "Extra virgin" olive oil (EVOO), for instance, is extracted from the olive fruit without using heat or chemical solvents. This mechanical process retains the highest amount of natural “phenolic compounds” — antioxidants and anti-inflammatory agents. Such compounds both retard oxidation in the olive oil (keeping it fresh and preventing rancidity) and confer health benefits.

Miller's diagram (above) depicts the fatty acid content of olive oil. PUFA is polyunsaturated fatty acids.


"Antioxidants combat cell and tissue damage due to oxidation, and anti-inflammatory agents reduce inflammation throughout the body. Inflammation can lead to an array of diseases (arthritis, coronary artery disease and more),” said Amy Myrdal Miller, registered dietitian and a program director at The Culinary Institute of America.

When oils are 'refined,' heat or chemical solvents strip away phenolic compounds; the result is often a bland flavor. Mechanically extracted "extra-virgin" oils retain aromatic components.  Pungent, peppery and sometimes bitter notes signal that an oil contains phenolics.

The growth of premium olive oil production in California has its roots in 1997, when UC Cooperative Extension Sonoma County Advisor Paul Vossen started the first olive oil taste panel in California to help producers improve oil quality using sensory analysis. (See the January 2011 California Agriculture.)

When it comes to detecting positive and negative attributes of olive oil, human tasters are superior to current chemical analytical methods. Standards to define "extra-virgin" and other grades of oil include both sensory and laboratory measures. The International Olive Council's (IOC) narrow definition specifies that EVOO must show no evidence of heat or chemical solvents. It must have zero median "defects" (as judged by trained taste panels) and more than zero median fruitiness. It must meet requirements for low levels of free fatty acids (too many of these signal degradation) and peroxide levels (a sign of oxidation).

This definition has been adopted by the U.S. Department of Agriculture (USDA) and the states of California, Connecticut and Oregon. Beginning on Oct. 24 of 2010, it became part of new USDA standards for olive oil labeling, which also define "U.S. Virgin,"  "U.S. Refined" and other grades.  Although the standards are voluntary, any manufacturer using this terminology on its label could be held to truth-in-labeling laws.

While the ultimate impact of the new USDA standards will take time, consumers can learn to identify flavor attributes of California olive oils by participating in tastings at vendors that feature artisan products. Also, the

California Olive Oil Council awards an extra-virgin certification seal to member oils that are defect-free.

However, the array of olive oils now available at supermarkets can be daunting, and "extra virgin" on the label can be misleading. The UC Davis Olive Center reported in July 2010 that their samples from Sacramento, San Francisco and Los Angeles supermarkets revealed 69 percent of imported EVOO and 10 percent of California olive oil samples labeled as EVOO failed to meet International Olive Council (IOC)/USDA sensory standards for extra virgin olive oil.

Once you identify your favorite olive oil, it should be stored in a cool, dark environment, like a kitchen cabinet removed from the stove, according to Alexandra Vicenik Devarenne, freelance olive oil consultant in Sonoma County. Fluctuations in temperature and light affect the integrity of the health-promoting phenols in extra virgin olive oil.

“When people find out about phenolics and the effects of heat on olive oil, they may question whether it is safe and okay to cook with extra virgin olive oil,” she says. “The heat will destroy some of the health-promoting phenols in the oil, which will change the flavor. The longer the oil is exposed to heat, and the higher the heat, the more phenols will be destroyed.

“However, sautéing in extra virgin olive oil for 5 to 10 minutes over medium heat will have minimal effects on phenols and flavor.”


See more tips on storing and cooking with olive oil.







Posted on Tuesday, November 23, 2010 at 5:10 PM
  • Author: Janet L. White

A feast grows in Baldwin Park

The Baldwin Park Community Garden sits in the shadow of the San Bernardino Freeway in Eastern Los Angeles County. As the cars rush by, an effective and innovative community garden grows. A unique public-private partnership has made this garden possible to benefit the community and local children.

The garden, which is approximately a quarter acre in size, has both school and community plots. The land and financial support are provided by Kaiser Permanente. The City of Baldwin Park helps to maintain the garden. The Baldwin Park Unified School District uses the garden to engage fourth graders from four classrooms at two elementary schools in hands-on nutrition education through a project called “The Moveable Feast.”

The Moveable Feast conducts in-garden nutrition lessons, each of which includes an easy, healthy recipe using garden produce. Each month’s nutrition lesson ties into cultural and community awareness. For example, as the recession deepened, Moveable Feast Director Linda Hahn wanted lessons to tie in with the growing problem of hunger in the community.  She had students prepare two “Rainbow Pita Pocket Sandwiches,” one for themselves, and one for a person in need. Hahn worked with the local food bank to distribute the extra sandwiches.

The garden activities have had a measurable impact on the kids. A survey of the students suggested that 87 percent eat more fruits and vegetables after having participated in the garden.

We receive many requests from teachers, community members and others who are interested in starting gardens. Our Common Ground Garden Program at UC Cooperative Extension in Los Angeles provides printed resources, and sometimes the support of UC Master Gardener volunteers.

Over the years, we've seen many projects succeed, and also many projects that come and go. The Baldwin Park Garden is a great example and seems to have three key ingredients that help to ensure and sustain its success:

  1. Institutional support. Three entities, Kaiser Permanente, the City of Baldwin Park, and the Baldwin Park Unified School District are deeply invested in this project, and support it either financially or through significant in-kind contributions.

  2. Meaningful youth involvement. Teachers and the school district, via the Moveable Feast, engage children in effective, measurable garden-based learning that’s tailored to the needs of the community.

  3. Promotion of the project to the community and key decision makers. The Moveable Feast has a “Guest Chef” program that brings in local leaders to see and participate in the garden. Student essay competitions, a garden cookbook and thank-you celebrations also help to promote and further engage the community in this endeavor.

For the kids, its success is very simple. As one student stated, "The garden is the best place I have gone since I entered fourth grade. It is the best garden in the world."

Rainbow Pita Sandwiches - RECIPE
Rainbow Pita Sandwiches - RECIPE

Posted on Friday, November 19, 2010 at 12:23 PM

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