UC Food Blog
How are you celebrating American agriculture in your life? In advance of National Ag Week, March 19-25, and National Ag Day, March 21, Central Valley third-grade students were “learning with lettuce” how to bring more agriculture into their lives last week. The UC Kearney Agricultural Research and Extension Center offers the free lettuce plantings every year at Farm and Nutrition Day in Fresno County and Kings County, typically around the time of National Ag Week.
Students with the help of volunteers learned how to plant tiny lettuce seedlings into a pot of healthy soil to take home for transplanting later. In addition to helping the students connect their food to agriculture, the lettuce planting offered an engaging, hands-on experience growing healthy and nutritious food at home.
National Ag Week is a nationwide effort coordinated by the Agriculture Council of America to tell the vital story of American agriculture and remind citizens that agriculture is a part of all of us. National Ag Day encourages every American to:
• Understand how food and fiber products are produced.
• Appreciate the role agriculture plays in providing safe, abundant and affordable products.
• Value the essential role of agriculture in maintaining a strong economy.
• Acknowledge and consider career opportunities in the agriculture, food and fiber industry.
Each American farmer feeds about 144 people. As the world population soars, there is even greater demand for the food, fiber and renewable resources produced in the United States. Agriculture is this nation's #1 export and incredibly important in sustaining a healthy economy. That's why National Ag Week is a great time to reflect on and be grateful for American agriculture.
California tree nut growers will soon have to comply with new agriculture water testing requirements under the Produce Safety Rule in the 2011 Food Safety Modernization Act (FSMA). University of California researchers and advisors are holding seminars to share information about the agricultural water requirements and proper water sampling methods in order to be in compliance with the regulations.
While irrigation or spray water is generally not the source of contamination, it is a vehicle for pathogens that are harmful to humans, especially on produce that is consumed raw; therefore, agricultural water was included as a part of the new regulation.
The UC Cooperative Extension office in Yolo County was the site of the first information sessions for nut tree growers/producers. It was an ideal location, as the fertile soils of the Sacramento and San Joaquin valleys are home to the largest tree nut production industries in the U.S. Some nuts are also grown in the coastal valley regions and Sierra foothills.
Good news for nut consumers
The new regulations and the focus on food safety practices, particularly within the nut tree industry, is of great interest because of the popularity of nutritious and delicious tree nuts. I for one am a big consumer. My day starts with almond butter on toast. That's followed by snacks of raw walnuts and dates. And there's always the handful of roasted pistachios to be grabbed for a salty treat.
It is lucky for someone who is nuts about nuts to live in California. The state is the nation's No. 1 walnut, almond and pistachio producer. California produces 80 percent of the world's almonds. We produce one million tons of almonds each year, followed by walnuts at nearly half a million tons, and pistachios at over a quarter million tons.
The California Department of Food and Agriculture reports the state's leading agricultural export products by value in 2015 were almonds ($5.14 billion), dairy products ($1.63 billion), walnuts ($1.49 billion), wine ($1.48 billion), and pistachios ($848 million).
Melissa L. Partyka, an ecologist at the UC Davis Western Institute for Food Safety and Security, (WIFSS) and Ronald F. Bond, a water quality researcher and field coordinator with WIFSS, are engaging local growers on issues of food safety and helping to educate them on not only the regulations but on ways to improve their water quality.
Partyka and Bond are staff in the UC Agriculture and Natural Resources' Vet Med Extension and Atwill Water and Foodborne Zoonotic Disease Laboratory, headed by UC Cooperative Extension specialist Rob Atwill, director of WIFSS.
They are affiliated with the Western Center for Food Safety, a Food and Drug Administration Center of Excellence, and are helping break down the regulations for the growers, regulations which can be a little overwhelming to the untrained.
Agricultural water, according to FSMA, is that water used to irrigate, treat, harvest, wash commodity or equipment on farm.
Growers are required to test water if it:
- Comes in contact with the harvestable portion of the commodity
- Is used to clean harvest equipment
- Is used to mix pesticides/fungicides applied to commodity
- Is used by harvest crews to wash hands
As of January 2016 growers will have 2 to 4 years (depending on farm size) to comply with most aspects of the Produce Safety Rule. Basically, the larger the production, the higher potential for risk to the consumer. How often a grower samples water depends on the water source. Well water requires an initial four samples, followed by one sample per year. Surface water, requires an initial 20 samples, followed by five samples per year. Water samples should be collected as close to harvest as is practical. During a long harvest season, samples can be spread out; in short harvest seasons, samples should be collected closer together; and in multiple harvest seasons, samples should be taken near each harvest if water is coming from the same source.
A full day workshop to be hosted by UC Cooperative Extension is planned for late June. Look for announcement of date, time, and location on the following websites: www.wcfs.ucdavis.edu, http://ucanr.edu, www.wifss.ucdavis.edu.
Get a jump start on your spring-summer vegetable garden. Start growing seedlings indoors now to have young plants ready to go into the ground when the weather warms and there is no longer a threat of frost. Growing vegetables from seeds is a passion for many avid gardeners, but even a novice gardener can have fun and success with a little planning and effort.
While growing vegetables from seed requires a little bit of extra work, germinating your own seeds gives you access to a wider variety of vegetables than typically available from a local nursery. Many gardeners love experimenting by growing exotic or unusual flavors, colors, size or texture of their favorite edible.
What you will need:
Growing healthy seedlings starts with healthy and high-quality seeds. Make sure to purchase seeds from a reputable supplier, and read the instructions and recommendations on the seed packets for specific planting instructions.
Keep in mind that if you save seeds from your own garden, the plants they produce in the future may not be identical to their parents because they are a result of random open pollination. When saving your own seeds, clean and dry them and then place them in a container that will keep them dry. Store seeds in a cool location.
- Germination mix
To start your seeds off right do not use garden soil or potting mix. Potting or garden soil it is too heavy, not sterile and does not drain well. It is recommended to use a germination mix that is a combination of one-third sterilized sand, one-third vermiculite and one-third peat moss which allows for air to circulate and is able to hold moisture, but still drains well.
There are a variety of container options available for purchase, including flats or trays with dividers, or you can use small individual clay or plastic pots. It is also possible to use recycled items found around the house, like milk cartons, toilet or paper towel rolls, and plastic containers from yogurt to name a few. It is important to wash all containers thoroughly and soak and rinse in a solution of 1 part chlorine bleach to 9 parts water, to help prevent diseases from occurring to your delicate seedlings.
- Light source
Edible plant seedlings typically need a bright light source to develop into healthy plants. Oftentimes, indoor seed germination requires more lighting than what is available from a large window. When more light is needed, suspend fluorescent lights 6 to 12 inches above the seeds for approximately 16 hours per day. After the seeds have germinated, move the seedlings to a cool, south facing window with plenty of natural light. Check seed packets for specific germination tips for individual species.
- Heat source
Most seeds have a minimum and maximum optimal temperature at which they germinate, check seed packets or catalog for recommended germination temperatures. Temperature is extremely important in having the highest germination success (see table). Most edible plants germinate faster in warm soil (75°-85°F), to provide a consistent heat source a heating mat can be used. Once seeds have sprouted the seedlings prefer slightly cooler temperatures so a heating mat is no longer needed.
Soil temperature conditions for vegetable seed germination, from the California Master Gardener Handbook (table 5.2):
Germination begins with the seed absorbing water. An adequate, continuous supply of water is needed to ensure successful germination. Once the germination process has begun try and avoid any dry or overly wet periods that may cause the young seedling to die.
After experiencing the wonder of watching a seed turn into a mature seedling it is time to transplant. To transplant, carefully dig out and lift the small plant out of its container. Prepare its new desired location by making a hole the same size and depth as where the seedling was growing, once placed firm the soil and gently water. When possible keep the newly transplanted seedling out of direct sun and heat for a few days.
Learn more with the UC Master Gardener Program
Interested in learning more about how to start seedlings or how to grow an edible garden? The UC Master Gardener Program has University-trained volunteers who are eager to help. Volunteers are available to answer questions about preparing your soil, fertilizing, mulching and more. With local programs based in more than 50 counties across California there is sure to be a workshop or class near you. Visit our website to find your local UC Master Gardener Program, mg.ucanr.edu.
What is the role of trust in our food system? Here in the United States, our trust in food is often implicit. We can generally trust that the fruits and vegetables we buy at a grocery store or farmers market are safe to eat — and we are often free to shop without even thinking about that trust.
Between farmers and agricultural scientists too, trust often plays an important role. If you're a farmer, you need to be able to trust that investing your time or money in a new technique or in attending a workshop will indeed improve your business.
But it can be easy to forget that trust is a critical first step in many of these agricultural relationships.
Establishing trust between actors in a food system has been critical for a Horticulture Innovation Lab project in Cambodia, focused on increasing the amount of safe vegetables available to Cambodian consumers. Project leaders from UC Davis and UC ANR — Glenn Young, Jim Hill, Cary Trexler, David Miller and Karen LeGrand — are actually traveling right now in Cambodia to launch a new phase of this project. They are partnering with scientists from Cambodia's Royal University of Agriculture and the University of Battambang. The researchers plan to expand upon their past successes, working together with farmers, marketers, and input suppliers to build trust while building safe vegetable value chains.
One key to their past success was that before introducing farmers to new agricultural technologies, the researchers first connected with farmers socially, by starting community savings groups. In these savings groups, farmers could build relationships and trust, while increasing their own savings and accessing small loans.
This social aspect of the project was the focus of a video made by UC Davis graduate students Thort Chuong, Elyssa Lewis, and Katie Hoeberling. This 3-minute video was a finalist in the World Food Day Video Challenge:
Building trust and resilience in a safe vegetable value chain in Cambodia Interviews for the video were conducted as part of a student thesis and supported by the U.S. Borlaug Graduate Research Fellowship program.
Though he is now studying at UC Davis as a Fulbright Fellow, Chuong was originally hired to work with farmers on the first phase of this project in Kandal province as an agronomist and field facilitator.
“At first I just wanted to focus on the agronomy part,” he said. “But then I saw the advantages of being a [savings group] member and thought, wow, this is a great thing to do.”
In fact the advantages were so great that on the weekends he returned to his hometown, gathering his neighbors and relatives together to start their own savings groups. Members have a safe way to save money, an easier way to secure small loans, and earn a little interest too.
Farmers in these savings groups were able to save considerable amounts of money and provide loans to each other for things like seeds, field preparation, labor costs, school fees, wedding costs, even in one case a new house — with each member contributing $5-25 per week for a year.
With trust and community established, some of the farmers in the savings groups also decided to try out a new agricultural technology in partnership with the scientists, using nethouses for pest management to avoid spraying pesticides. (In many countries where pesticide information is inaccessible to the average farmer, it is not uncommon for farmers to keep a separate garden to feed their family — in order to avoid eating even their own crops that they are selling to the market.)
The new, safe vegetable value chain they were part of grew and strengthened, as the international team connected these farmers to a marketer who needed to source vegetables grown without pesticides. That marketer then sells those vegetables to consumers in the capital city of Phnom Penh, who were able to trust the vegetables they bought from her are indeed safe to eat.
The Horticulture Innovation Lab is led by a team at UC Davis, with funding from the U.S. Agency for International Development, as part of the U.S. government's global hunger and food security initiative called Feed the Future. Learn more about Horticulture Innovation Lab researchers and their projects in Asia, Africa and Central America.
When it comes to nursing moms and their babies, an elegant web of cause and effect connects climate, breast milk, gut microbes and infant health.
That web was clearly illustrated by a recently published study involving 33 women and their babies in the West African nation of The Gambia. The research team, including scientists from UC Davis and UC Agriculture and Natural Resources, found that complex breast milk sugars called oligosaccharides helped protect nursing babies from illness and also influenced the mixture of microbes in the infants' guts.
The researchers also showed that changes in food availability from season to season could affect the composition of the women's breast milk and the protective quality of the babies' gut microbiota. And those changes, in turn, impacted the health and growth of the breastfed infants.
Composition of breast-milk sugars and infant health
Oligosaccharides occur abundantly as more than 200 different chemical structures in human breast milk. It's been known for some time that these complex sugars contribute to infant health by supporting the growth of beneficial bacteria in the baby's gut. And these gut bacteria have been shown to play a key role in fending off infectious illnesses.
But little has been known about how changes in the composition of the breast milk sugars might affect the health and growth of infants, especially those living in areas where infection rates are high.
To explore that relationship, the researchers monitored the composition of the oligosaccharides in the mothers' milk and examined the infants' gut microbiota at 4 weeks, 16 weeks and 20 weeks after the babies were born. Then they analyzed the data, looking for possible relationships to the health and growth of the babies and the status of their gut microbes.
They found that two of the oligosaccharides, lacto-N-fucopentaose and 3′-sialyllactose, had a direct relationship to the babies' health and growth. High levels of the former were associated with a decrease in infant illness and with improved growth, measured as height for age, while the latter proved to be a good indicator of infant growth, measured by weight per age.
“Our findings provide evidence that specific human milk oligosaccharides can alter the composition of breast milk, making it more protective against infection and allowing the infant to invest energy in growth rather than fending off disease,” said the study's corresponding author Angela Zivkovic, an assistant professor of nutrition at UC Davis.
Influence of wet and dry seasons
The researchers also were curious how seasonal shifts in food availability, which significantly impact the mothers' diets, might be reflected in breast milk composition and infant health.
The Gambia has two distinct seasons, the wet season from July to October and the dry season from November to June.
The wet season is also known as the “hungry” season because it is the time of year when food supplies tend to be depleted, infection rates rise and the farming workload is highest. In contrast, the dry, or “harvest,” season is characterized by plentiful food supplies as well as significantly higher energy stores and less illness among the local people.
The researchers found that mothers who were nursing during the wet or “hungry” season produced significantly less oligosaccharide in their milk than did those nursing during the dry season.
In examining the makeup of the babies' gut microbiota, the researchers noted that most of the bacteria belonged to the Bifidobacteria genus. They also discovered that higher levels of Dialister and Prevotella bacteria were accompanied by lower levels of infection.
In addition, higher levels of Bacteroides bacteria were present in the infants' guts that had abnormal “calprotectin” – a biomarker associated with intestinal infections.
“We are very interested in which specific dietary factors influence the oligosaccharide composition of mother's milk,” Zivkovic said. “If we can find the mechanisms that change the composition of breast milk sugars, we may have a new approach for modifying the infant microbiota and ultimately influencing the health and vigor of the nursing baby.”
The study by Zivkovic and colleagues appears online in the journal Scientific Reports. The research is part of a long-running, cross-disciplinary project at UC Davis examining milk and its role in nutrition.
Funding for the study was provided by the National Institutes of Health, UK Medical Research Council, Bill and Melinda Gates Foundation, Alfred P. Sloan Foundation, and Peter J. Shields Endowed Chair in Dairy Food Science at UC Davis.