A summer of smoke and ash in many parts of California has raised questions about the safety of produce growing on farms and in the garden, eggs laid by chickens who peck around in ash-laden areas, and remediation needed to safely and effectively grow food in the future.

UC Agriculture and Natural Resources brought together experts who have researched the effects of previous fires' fallout and studied soil contaminants to share their insight in a two-hour webinar now available on YouTube.

“The No. 1 health concern during a fire is smoke inhalation, and it's been well documented that wildfire smoke can negatively impact both the heart and the lungs,” said Claire O'Brien, a pharmacology and toxicology doctoral student at UC Davis. “However, the chemicals found in the smoke don't just stay in the air. They can deposit onto plants and into soil and water.”

Always wash your hands before and after harvesting, and wash your produce in running water to mitigate a potential risk. (Photo: Evett Kilmartin)

Although every fire is unique, some generalizations can be drawn from research conducted following previous fires. UC Cooperative Extension food systems advisor Julia Van Soelen Kim detailed a study conducted following the October 2017 wildfires in Sonoma County and across the North Bay.

With the help of UC Master Gardener and community volunteers, the researchers collected over 200 samples of homegrown collard greens, lettuces, kale and chard that were exposed to wildfire smoke and ash. A subset of the samples were analyzed by a private laboratory.

 “There was very low concern about chemicals on produce,” Van Soelen Kim said. “No samples had detectable levels of lead, arsenic, mercury or chromium. And that's a huge sigh of relief.” However, analytical results vary by site, site history and by fire event, and few have pre-fire baseline data to compare with.

Van Soelen Kim said basic food-safety practices should be followed when preparing to eat food grown in a home garden, regardless of ash or smoke contamination.

“You should always wash your hands before and after harvesting, and wash your produce in running water to mitigate any kind of potential risk,” she said.

Keeping chicken feed off the ground and providing clean water are two ways to reduce the risk of contaminated eggs. (Photo: USDA)

Are backyard chicken eggs safe to eat?

Another study outlined at the webinar used a similar process to determine whether there might be contaminants in the eggs laid by backyard poultry that live and feed in areas exposed to wildfire ash and smoke.

Scientists know from previous research that chickens exposed to lead in their environment can produce eggs with high lead content and that heavy metal content of ash from urban wildfires is higher than from rural wildfire.

“We combined those two pieces of research with what we know that chickens do all day: they peck at the ground for hours on end,” said Todd Kelman, a veterinarian in the School of Veterinary Medicine at UC Davis. “That makes for a pretty good hypothesis that urban wildfire could pose a risk for the production of eggs and poultry that contain heavy metals.”

Kelman and his team put out a call for eggs from backyard poultry and received samples from 344 premises in fire-affected and non-fire-affected areas of California.

Surprisingly, egg samples that contained higher lead levels came from parts of the state that were not directly impacted by ash and smoke.

“Did our data support our hypothesis that proximity to urban wildfire is a driving source for lead in eggs of backyard poultry? The answer is not so much,” Kelman said. “So, is it safe to eat eggs from your backyard poultry? We can't give you a definitive answer to that question. But we do suggest you assess your risk and reduce the risk of contamination.”

Practices that reduce the risk include keeping chickens off the ground, using a chicken feeder that prevents spillage onto the ground and making calcium readily available, for example in the form of oyster shells, because calcium can prevent the absorption of lead. Making sure that chickens are provided uncontaminated water is also an important part of risk reduction.

For confirmation on the safety backyard chickens and their eggs, lab tests for eggs are available for $60 from the California Animal Health and Food Safety Laboratory at UC Davis, or chickens may be submitted to CAHFS for necropsy.

The UC Master Gardener Program can provide technical assistance to help home gardeners find resources for home soil testing. (Photo: USDA)

Are soils safe for growing food after a fire?

Fire effects on soil is another consideration in burned areas, said UC Cooperative Extension urban agriculture advisor Rob Bennaton.

“Fires heat topsoil layers. They reduce the amount of living micro-organisms at the site of the burn, and also affect organic matter and nutrients. Ash deposits over time may make soils more alkaline,” he said. “As a result of these combined factors, there are temporary changes in nutrient levels and the capacity for soils to exchange nutrients for optimal plant growth and nutrition.”

With proper land care and management, soils can be remediated over time.

“It won't happen overnight. Soils were developed over millions of years,” he said.

Some ways to improve safety when gardening in fire-affected areas including keeping the soil covered with wood chips or other landscape mulch to reduce airborne soil dust. Use drip irrigation to prevent up splash onto the undersides of growing vegetables. Promote good drainage, especially at the bottom of slopes to prevent the concentration of contaminants.

Lab tests are often needed to determine the soils' post-fire characteristics. “Don't guess, but test,” Bennaton said.

The UC Master Gardener Program can provide technical assistance to help home gardeners find resources for home soil testing, he said.

Additional resources and information shared during the webinar include: 

Post-fire soil resources and soil testing information

• UCCE publication on Soils in Urban Agriculture with soil testing & sampling information
• The UC ANR Healthy Soils Website, which has many resources worth reviewing.
• Tips for Interpreting Soil Analysis
• UC Master Gardener of Sonoma County 2018 workshop video “Effects of fire on soil”

Post-fire food safety

• Research on produce safety and backyard chicken egg safety after the 2017 wildfires in California is available on this web page. To view a past webinar recording with these research findings, click this link.
• Poultry wildfire resources from the UC Davis School of Veterinary Medicine:
• Best Practices for Produce Safety After Fire
• Understanding Risk: A community guide for assessing the potential health impacts of locally grown produce exposed to urban wildfire smoke

Firewise and sustainable home landscaping design in the defensible space zone

• Visit the UC Master Gardener Program of Sonoma County firewise landscaping web page.
• For a recent firewise & sustainable design and maintenance video by the Resilient Landscapes Coalition.

Impact of smoke & ash on plants

• UC Berkeley Botanical Garden blog post on "The Effects of smoke and ash on plants" 

[This article was first published Nov. 3, 2020]

A summer of smoke and ash in many parts of California has raised questions about the safety of produce growing on farms and in the garden, eggs laid by chickens who peck around in ash-laden areas, and remediation needed to safely and effectively grow food in the future.

UC Agriculture and Natural Resources brought together experts who have researched the effects of previous fires' fallout and studied soil contaminants to share their insight in a two-hour webinar now available on YouTube.

“The No. 1 health concern during a fire is smoke inhalation, and it's been well documented that wildfire smoke can negatively impact both the heart and the lungs,” said Claire O'Brien, a pharmacology and toxicology doctoral student at UC Davis. “However, the chemicals found in the smoke don't just stay in the air. They can deposit onto plants and into soil and water.”

Always wash your hands before and after harvesting, and wash your produce in running water to mitigate a potential risk. (Photo: Evett Kilmartin)

Always wash your hands before and after harvesting, and wash your produce in running water to mitigate a potential risk. (Photo: Evett Kilmartin)

Although every fire is unique, some generalizations can be drawn from research conducted following previous fires. UC Cooperative Extension food systems advisor Julia Van Soelen Kim detailed a study conducted following the October 2017 wildfires in Sonoma County and across the North Bay.

With the help of UC Master Gardener and community volunteers, the researchers collected over 200 samples of homegrown collard greens, lettuces, kale and chard that were exposed to wildfire smoke and ash. A subset of the samples were analyzed by a private laboratory.

 “There was very low concern about chemicals on produce,” Van Soelen Kim said. “No samples had detectable levels of lead, arsenic, mercury or chromium. And that's a huge sigh of relief.” However, analytical results vary by site, site history and by fire event, and few have pre-fire baseline data to compare with.

Van Soelen Kim said basic food-safety practices should be followed when preparing to eat food grown in a home garden, regardless of ash or smoke contamination.

“You should always wash your hands before and after harvesting, and wash your produce in running water to mitigate any kind of potential risk,” she said.

Keeping chicken feed off the ground and providing clean water are two ways to reduce the risk of contaminated eggs. (Photo: USDA)

Keeping chicken feed off the ground and providing clean water are two ways to reduce the risk of contaminated eggs. (Photo: USDA)

Are backyard chicken eggs safe to eat?

Another study outlined at the webinar used a similar process to determine whether there might be contaminants in the eggs laid by backyard poultry that live and feed in areas exposed to wildfire ash and smoke.

Scientists know from previous research that chickens exposed to lead in their environment can produce eggs with high lead content and that heavy metal content of ash from urban wildfires is higher than from rural wildfire.

“We combined those two pieces of research with what we know that chickens do all day: they peck at the ground for hours on end,” said Todd Kelman, a veterinarian in the School of Veterinary Medicine at UC Davis. “That makes for a pretty good hypothesis that urban wildfire could pose a risk for the production of eggs and poultry that contain heavy metals.”

Kelman and his team put out a call for eggs from backyard poultry and received samples from 344 premises in fire-affected and non-fire-affected areas of California.

Surprisingly, egg samples that contained higher lead levels came from parts of the state that were not directly impacted by ash and smoke.

“Did our data support our hypothesis that proximity to urban wildfire is a driving source for lead in eggs of backyard poultry? The answer is not so much,” Kelman said. “So, is it safe to eat eggs from your backyard poultry? We can't give you a definitive answer to that question. But we do suggest you assess your risk and reduce the risk of contamination.”

Practices that reduce the risk include keeping chickens off the ground, using a chicken feeder that prevents spillage onto the ground and making calcium readily available, for example in the form of oyster shells, because calcium can prevent the absorption of lead. Making sure that chickens are provided uncontaminated water is also an important part of risk reduction.

For confirmation on the safety backyard chickens and their eggs, lab tests for eggs are available for $60 from the California Animal Health and Food Safety Laboratory at UC Davis, or chickens may be submitted to CAHFS for necropsy.

The UC Master Gardener Program can provide technical assistance to help home gardeners find resources for home soil testing. (Photo: USDA)

The UC Master Gardener Program can provide technical assistance to help home gardeners find resources for home soil testing. (Photo: USDA)

Are soils safe for growing food after a fire?

Fire effects on soil is another consideration in burned areas, said UC Cooperative Extension urban agriculture advisor Rob Bennaton.

“Fires heat topsoil layers. They reduce the amount of living micro-organisms at the site of the burn, and also affect organic matter and nutrients. Ash deposits over time may make soils more alkaline,” he said. “As a result of these combined factors, there are temporary changes in nutrient levels and the capacity for soils to exchange nutrients for optimal plant growth and nutrition.”

With proper land care and management, soils can be remediated over time.

“It won't happen overnight. Soils were developed over millions of years,” he said.

Some ways to improve safety when gardening in fire-affected areas including keeping the soil covered with wood chips or other landscape mulch to reduce airborne soil dust. Use drip irrigation to prevent up splash onto the undersides of growing vegetables. Promote good drainage, especially at the bottom of slopes to prevent the concentration of contaminants.

Lab tests are often needed to determine the soils' post-fire characteristics. “Don't guess, but test,” Bennaton said.

The UC Master Gardener Program can provide technical assistance to help home gardeners find resources for home soil testing, he said.

Additional resources and information shared during the webinar include: 

Post-fire soil resources and soil testing information

• UCCE publication on Soils in Urban Agriculture with soil testing & sampling information
• The UC ANR Healthy Soils Website, which has many resources worth reviewing.
• Tips for Interpreting Soil Analysis
• UC Master Gardener of Sonoma County 2018 workshop video “Effects of fire on soil”

Post-fire food safety

• Research on produce safety and backyard chicken egg safety after the 2017 wildfires in California is available on this web page. To view a past webinar recording with these research findings, click this link.
• Poultry wildfire resources from the UC Davis School of Veterinary Medicine:
• Best Practices for Produce Safety After Fire
• Understanding Risk: A community guide for assessing the potential health impacts of locally grown produce exposed to urban wildfire smoke

Firewise and sustainable home landscaping design in the defensible space zone

• Visit the UC Master Gardener Program of Sonoma County firewise landscaping web page.
• For a recent firewise & sustainable design and maintenance video by the Resilient Landscapes Coalition.

Impact of smoke & ash on plants

• UC Berkeley Botanical Garden blog post on "The Effects of smoke and ash on plants" 

Urban Agriculture Soil Information

• Urban Agriculture

In a growing number of communities, food policy councils (also called “food system alliances”) have emerged to address gaps in local policies that focus on food. Most communities have transportation, housing or land use policies, but food policies are frequently missing. Food policy councils (FPCs) are an important way to bring community members together with local government to promote the social, economic and environmental health of local and regional food systems.

Food policy councils are made up of representatives from many sectors in the food system, including farmers, distributors, retailers, food service operations, government agencies (like public health, county social services and county agriculture departments), and community organizations that work in the food system. Some FPCs also develop close partnerships with county-based UC Cooperative Extension to help facilitate their work.

FPCs support a variety of food and agriculture-related policies and programs, including healthy food access, land use planning, regional food procurement, food waste, food and economic development, local food processing, and regulations related to urban farming or community gardening, to name a few examples.

Community members meet at food policy summit in 2017.

A brief history of food policy councils

FPCs emerged in the late 1980s as the sustainable agriculture and food/nutrition movements began to pay more attention to community food systems. Early FPCs were created through resolutions of local government bodies (Clancy et al 2008). At that time, they tended to be embedded within government, much like a planning commission or a social service commission. As the local food movement began to rapidly expand in the 2000s, many local activists and organizations began to create FPCs as a way to bring together a more diverse group of food system stakeholders. These newer generation FPCs were typically organized outside of government as a non-profit organization or community coalition. Studies of FPCs, including our own, find that they take very diverse organizational forms and tackle widely varying issues, which means that generalizations about their goals and outcomes are difficult to make. This may be quite appropriate however, given the enduring FPC goal of tailoring food policies to the specific characteristics of particular places.

A UC ANR research project is looking at how FPCs work

While FPCs are increasingly on the radar of those trying to promote food system change, we still don't have much recent documented evidence about the actual work of FPCs (though see Harper et al. 2009, Fox 2010 and Borron 2003). In response, a team of UC Cooperative Extension researchers (Clare Gupta, Julia Van Soelen Kim, Dave Campbell, Jennifer Sowerwine, Gail Feenstra, Shosha Capps and Kate Munden-Dixon) began a comparative study of 10 California food policy councils in 2016. We wanted to know this: what are the networks and relationships that FPCs are a part of? And how do these networks and relationships influence what a FPC is able to achieve? As UCCE researchers ourselves, we were especially interested in understanding the nature of relationships between FPCs and university researchers, including UC Cooperative Extension.

To answer these questions, we interviewed more than 60 FPC members from food policy councils across California. We asked them about the work they were doing within their councils, their relationships with other players in the local food system, and the way they find information relevant for their council's priorities. We also led focus groups with members exploring the same questions. In addition, we analyzed documents produced by and about FPCs. We also engaged in “participant observation” — researcher lingo for the process of engaging with groups and individuals as a way to learn first-hand about what they do. Lastly, we combined the stories we heard from our interviewees with numerical data from a survey of nearly all of California's known FPCs. We hoped by doing this to develop a better picture of FPCs' strategies for gathering relevant information, networking and creating impact.

Our Research Findings

A full report of our findings can be found on the UC SAREP website, but here we share some key takeaways and strategies for FPC success:

• Respondents see information sharing as the most valuable FPC activity. It encourages collaboration and shifts participant thinking towards a more holistic view of food policy work.
• Members who are “knowledge brokers,,” including Cooperative Extension advisors, are connected to many different knowledge sources and are able to draw on these different sources to provide data and information that match their council's needs.
• Real-life experiences are often as compelling with policy-makers as statistics. FPCs cite the value of integrating information from numbers (i.e. quantitative data) and stories (i.e. qualitative data).
• There is no one-size-fits-all approach to FPC membership. Some FPCs view food system change as a process that involves a broad and inclusive consortium of stakeholders. They try to bring stakeholders with diverse values together (i.e., a “big tent” approach). Other FPCs emphasize attracting allies who share core values and a commitment to advocacy on behalf of food systems change (i.e., a “small tent” approach).
• Small sub-groups within FPCs can achieve significant policy change. A targeted sub-group of the FPC (i.e. working group; task force, campaign) can work with key allies to push forward a particular policy priority—the entire council does not necessarily have to be entirely involved.
• Effective FPCs have strong leaders. These leaders have deep experience and connections in the community and a good feel for the nuances involved in effective political organizing.

Overall, we found that the work of FPCs at the local and state level is making a significant difference in our state, providing a meaningful way to pursue food systems policy and change. Our recent article in the Journal of Agriculture, Food Systems and Community Development specifically highlights how local government and FPCs collaborate to shape food policies and programs in different local contexts. Stay tuned for more results from our work.

Get involved

We would love to hear from you about whether our findings resonate in your own food policy council, or if you have ideas for next research steps.

Want to get involved in local food system policy-making? Join a food policy council! See reports by Food First or Johns Hopkins Center for a Livable Future's Food Policy Networks for additional information.   

Citations

Clancy, K., Hammer, J., & Lippoldt, D. (2008). Food policy councils-past, present, and future. In Remaking the North American Food System: Strategies for Sustainability (pp. 121-143). University of Nebraska Press.

Borron, S.M. 2003. Food Policy Councils: Practice and Possibility. Congressional Hunger Center Hunger-Free Community Report.

Fox, C. 2010. Food Policy Councils: Innovations in Democratic Governance for a Sustainable and Equitable Food System. Los Angeles Food Policy Task Force unpublished report. 

Harper, A., Shattuck, A., E. Holt-Gimenez, Alkon, A., and F. Lambrick. 2009. Food Policy Councils: Lessons Learned. Food First: Institute for Food and Development Policy.

50 food and agriculture leaders from Sonoma County and the North Bay gathered on June 8, 2017 in Petaluma for the North Bay Food Policy Council Convening. Participants represented the Sonoma Food System Alliance and three North Bay food policy councils. Food Policy Councils are multi-stakeholder coalitions that work on devising local level solutions to nutrition, agriculture, and food systems issues.

Participants shared highlights of their work across the region, exchanged best practices and success stories, built skills in local policy advocacy, and sparked greater regional coordination between food policy councils. The event was hosted by North Bay Food Systems Advisor, Julia Van Soelen Kim, and UC Cooperative Extension. Based on the success of the event, it will likely be offered again in spring 2018.

For more information, contact Julia Van Soelen Kim, North Bay Food Systems Advisor