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UC Food Safety
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UC Food Safety

UC Food Blog

Farming for a safe, clean water supply

In most California homes there are few commodities more precious, or more taken for granted, than clean tap water. We use it without hesitation for drinking, cooking and washing produce.

However, recent news reminds us that not everyone can take clean water for granted. In rural California, where some households rely on well water, up to 2 million people have been exposed to unhealthy levels of nitrates in their water at some time during the last 15 years.

Synthetic fertilizers used in agriculture are major contributors of nitrates to our water, but a growing number of farmers are taking steps to reduce this problem by adopting micro and drip irrigation technologies, and by cultivating noncrop vegetation (buffer strips and cover crops) and “constructed wetlands.” All these measures reduce not only nitrates but many other pollutants from runoff.

"Nitrate problems start when applied fertilizer moves outside the root zones of plants," says Toby O'Geen, UC Davis soil resource specialist. "If nitrate reaches the root zone of actively growing crops, much of it is taken up by roots. But because of its high mobility, nitrate occurring outside the root zones can be transported by irrigation or rain as surface or subsurface runoff. "

Technologies like drip irrigation deliver water and fertilizer precisely to root zones. From 1991 to 2001, Califiornia growers decreased surface irrigation (furrow and flood) about 28 percent and increased sprinkler and drip/microirrigation about 28 percent (Orang et al 2008).

In addition, growers are using buffer strips, cover crops, vegetated waterways and constructed wetlands to purify water, reduce erosion, and remove hazardous contaminants such as pesticides, metals, pathogens and fertilizers. The Farm Bill funds some of these programs through the Environmental Quality Improvement Program and the Wetland Reserve Program.

"Farmers receive technical advice and funding to take marginal land out of production and put it into noncrop vegetation and creation of habitat, including constructed wetlands," O'Geen said.

The effectiveness of such measures depends on the site and the design, but they are probably the best way to reduce water pollution from runoff. (Taking regulatory action against any particular grower is not practical because the sources of nitrate pollution are widespread and occur regionally. Even isotope "fingerprints" often give mixed results because sources mix in the environment.)

Another way that agriculture helps remove pollutants of all kinds, including not only fertilizers and pesticides but pathogens, is through natural filtering by rangelands, including oak woodlands. (See details of how oaks help nitrogen cycling.) More than two-thirds of California's drinking-water supply passes through or is stored in oak woodlands. In fact, rangeland in California (land suitable for grazing livestock) comprises more than half of the state's 101 million acres and typically is not fertilized. It forms our major drainage basins – filtering the drinking water for millions of people. (see California Agriculture).

Border strips, shown on a Central Coast farm, <br> help improve water quality by filtering.
Border strips, shown on a Central Coast farm,
help improve water quality by filtering.

Posted on Friday, May 28, 2010 at 6:16 AM
  • Author: Janet L. White

Where's the beef?

By assigning a simple, 15-digit identification number to cows, UC researchers can track each one from conception to carcass, garnering valuable data for studies on cattle fertility, genetics, and health, and helping to select breeding animals with desirable beef characteristics such as flavor and tenderness.

In today’s beef market, an individual cow may change ownership many times during its lifetime as it travels from the ranch of its birth, to stocker and feedlot, to slaughterhouse, and finally supermarket or steakhouse. In the process, valuable data is lost along with the ability to “trace back” particular steaks to the original cow.

For several years, UC Davis researchers have been attaching a round, electronic ear tag to each newborn calf in the research herd at the UC Sierra Foothill Research and Extension Center, in the California foothills northeast of Sacramento.

The ear tags contain each cow’s unique radio-frequency-identification number, which is scanned with an electronic wand; the system is similar to that used to keep track of packages being shipped overnight or library books. Cowhands use a handheld device to enter information when the cattle are processed, which is transmitted via remote-access antennae to centrally located computer databases.

The integrated data-collection system is being used to undertake sophisticated studies on cattle genetics, with the ultimate goal of improving cattle breeding. “The genotype of some beef and dairy cattle may be better suited to grass-based productions systems,” UC Davis Cooperative Extension Specialist Alison Van Eenennaam and colleagues write in the April-June 2010 issue of California Agriculture journal. “It may also be possible to select animals that are able to grow to given size using less feed, or that are more resistant to certain diseases.

“These technologies also have great potential to enable the production of safer, more nutritious animal products. They may also allow for the selection of animals with a decreased environmental footprint and improved animal welfare due to lower levels of disease.”

Herd manager Dan Myers enters cattle <br>information into hand-held device.
Herd manager Dan Myers enters cattle
information into hand-held device.

Posted on Wednesday, May 26, 2010 at 7:56 AM
  • Author: Janet Byron

UC studies calorie labeling on cafeteria food

When food calorie content was posted on menu boards at Kaiser Hospital cafeterias, a significant number of patrons altered their food choices, according to a pilot menu labeling study conducted by UC Berkeley researchers.

The results are compelling because the California menu labeling bill (SB 1420), which requires chain restaurants to put calorie counts on menu boards, goes into full effect next year.

In the Kaiser pilot study, more than 500 patrons completed cafeteria exit surveys. Nearly a third of respondents who noticed the calorie information said they changed their food choices as a result. Nearly all of them agreed that calorie information should be available and 80 percent said they felt Kaiser was helping them look after their health by providing calorie and nutrient information.

The researchers also analyzed the food on patrons' trays - either by observation or by scrutinizing cash register receipts. They determined that food purchases in cafeterias where the labeling was introduced sold significantly more healthy side dishes, but little change was seen in entreé selections.

Eleven percent of the survey respondents indicated that there are potential disadvantages to having calorie information posted in the cafeterias, the research report said.

"The most common disadvantage cited was guilt from ordering high-calorie foods," it reported.

The pilot study was conducted by the Dr. Robert C. and Veronica Atkins Center for Weight and Health, the College of Natural Resources and the School of Public Health, all at UC Berkeley.

Click here for the 33-page research report.

Restaurant bagel labels with calorie counts.
Restaurant bagel labels with calorie counts.

Posted on Monday, May 24, 2010 at 7:34 AM

Eating right before, during and after a workout

It is "absolutely essential" to eat and drink two to four hours before workouts to fuel and hydrate the body, says UC Davis sports nutrition expert Liz Applegate. Eating before exercise is particularly important when taking part in activities that require hand-eye coordination, like basketball and fencing.

Applegate recorded a 13-minute video for the UC Cooperative Extension website Feeling Fine Online that outlines what and when athletes should eat for optimum health and performance.

The pre-workout meal, she advises, should be high in carbohydrates, low in fat and contain a moderate amount of protein. Applegate's examples:

  • 1 pita pocket with 3 tablespoons of fruit spread
  • 1 cup of oatmeal with 4 oz. of soy or lowfat milk
  • 6 oz. of vegetable juice with 1/2 cup apricots
  • High carbohydrate energy bar with no more than 10 grams of protein
During workouts, she advises athletes drink 1/2 to 3/4 cup fluid each 15 to 20 minutes. If the workout will last longer than an hour, consume about 100 calories each half hour. Foods to consume during workout sessions could include banana, apple, half a sandwich, sports drinks or energy gels.

"After exercise is where I see lots of mistakes," Applegate says.

She recommends athletes eat a specific amount of carbohydrates within the first 30 minutes post exercise. (To calculate the amount of post-exercise carbs for you, multiply your weight in pounds by 0.7. That gives the number of carbs in grams.) A small amount of protein and antioxidants will also boost recovery. Applegate's post-exercise examples are:

  • Smoothie with fruit and yogurt, protein powder or soy milk
  • Bean burrito with 6 oz. of fruit juice
  • Tuna sandwich with 8 oz. of cranberry juice
  • 2 mozzarella sticks, a whole grain English muffin and an orange

Recovery also requires rehydration. Applegate recommends drinking 16 oz. of fluid for each pound of sweat lost.

An apple after exercise aids recovery.
An apple after exercise aids recovery.

Posted on Friday, May 21, 2010 at 7:37 AM

New gardeners cultivated throughout Los Angeles County

Gardening has become very popular lately, particularly in growing fruits and vegetables, and largely due to the need to lower grocery bills and eat healthy during this recession.  But for beginners, gardening can sometimes seem intimidating and bewildering due to the multitude of variables involved, such as soil fertility, pest management, seasonal plants, composting, to name a few. Well, UC Cooperative Extension’s “Grow LA Victory Garden Initiative” in Los Angeles helped demystify gardening for many residents, using UC research-based information.

Master Gardener volunteers organized and led low-cost gardening courses to teach the basics of gardening to 297 students. Thirteen classes were held in March, April and May at 10 different sites throughout the county, from Tarzana to Echo Park. Each site accommodated about 30 participants who wanted to turn their new interest in gardening into successful, productive gardens in their backyards, community gardens and patios.  Overall, participants walked away very pleased with the classes, and many felt that their gardening knowledge improved significantly.

“My husband and I just want to say thank you for a really wonderful four-session course.  It was the perfect amount of information for beginner gardeners like us,” said a participant at the Milagro-Allegro Community Garden site in Highland Park, California.

So, what’s next?  Cooperative Extension hopes to host another round of classes in Fall 2010. The hands-on experience was very successful, leaving many to inquire about future classes. For information, please contact Yvonne Savio, Common Ground program manager, at (323) 260-3407, ydsavio@ucdavis.edu.

New gardeners learn the basics.
New gardeners learn the basics.

Posted on Wednesday, May 19, 2010 at 8:24 AM

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