On February 24, 2017, Georgia MGEVs had opportunity to attend Grow Strong! 2017, available in Athens and at 14 other remote sites. We had a GREAT response to the speakers with more questions than we could get answered in the time we had allowed! Our specialists graciously agreed to answer the ones we didn’t get to, and I promised to share them here. Our second speaker, Dr. Judy Harrison, Extension Food Safety Specialist in UGA’s Department of Foods and Nutrition, elaborates further on these questions about food safety in community, school, and home gardens.
- There is no treated lumber that claims to be eco-safe and could be used for raised beds, right?
Please visit the UGA College of Agricultural and Environmental Sciences Publication updated August 2016 by Drs. David Berle and Robert Westerfield entitled Raised Bed Materials (C 1027-5) at https://extension.uga.edu/publications/detail.cfm?number=C1027-5 for additional information on materials for safe use in raised bed gardens. This publication states:
“Commercial wood preservatives have come under scrutiny in the last several years, particularly creosote and some of the copper-based, pressure-treated products (for example, green stained wood used for decks). Due to the potential problems with creosote, used railroad ties and utility poles should not be used for beds that will be used to grow food of any kind. Similar concerns have been expressed over pressure-treated wood, though current formulations appear to be safe for food production. USDA Organic Certification guidelines do not allow any of the pressure-treated wood products to come in contact with plants grown for food.”
- What about letting chickens roam in the garden? And, I can’t keep my cats out of the garden!
Chickens can be carriers of Salmonella and Campylobacter, two types of bacteria that cause foodborne illness or as some people call it, “food poisoning”. Chickens should not be allowed to roam in the garden. Cats can carry the parasite, Toxoplasma gondii. CDC considers toxoplasmosis to be a leading cause of death attributed to foodborne illness in the U.S. Women who become newly infected with Toxoplasma during pregnancy or any person with a compromised immune system may have severe consequences if they become infected. A pregnant woman who becomes infected can pass the infection to her unborn child even if she has no symptoms. This can lead to miscarriages, stillbirths or severe problems for the unborn child such as nervous system diseases or eye disease.
Allowing animals to roam in gardens can be a source of microbial contamination that can lead to foodborne illness or other health consequences.
- How should we clean fresh produce from the grocery store-Diluted Vinegar solution?
Fresh produce, whether it is from the grocery store, farmers’ market or your own garden should be rinsed well under cool, running water that is safe to drink. Use a clean vegetable brush to wash hard skinned vegetables and fruits.
- If you cut off the damaged part of a lettuce leaf, are you less likely to get foodborne illness?
It certainly will not hurt to remove damaged parts of leaves or damaged areas on fruits and vegetables. However, if disease-causing microorganisms get in or on fruits and vegetables they are difficult, if not impossible, to remove. If they are inside the fruit or vegetable, they may not just stay in one spot. The key to food safety with produce is to not let the product become contaminated with disease causing microbes by using good agricultural practices that minimize opportunities for contamination to occur.
- With the advent of modern day grocery stores using regular water misting, is there a greater chance for contamination due to the excess moisture on the produce or irregular cleaning of misters?
There have been no outbreaks of foodborne illnesses linked to grocery store misters. There is no scientific evidence that shows that produce products misted is stores are more likely to be contaminated with foodborne illness causing microbes than those not misted.
- How long do contaminates from cat and dog fecal matters last in soil?
Regardless of the source, bacterial pathogens such as Salmonella and E. coli O157:H7 have been found to survive from several days to almost a year in soil, depending on the type of soil, the level of moisture, the temperature, etc. The same is true for parasites. Survival and ability to infect is different for different parasites depending on the organism, the type of soil, temperature, etc.
- What do you treat the water from rain barrels with?
Research has shown that run-off from roofs can be contaminated not only with disease-causing microorganisms, but also with chemicals such as lead, zinc and polycyclic aromatic hydrocarbons. Especially in school and community gardens, it is safest to use water from rain barrels on ornamental plants and not on edible plants. The USDA Food and Nutrition Service recommends testing water from rain barrels before using it in school gardens. It is easier just to use that water on ornamental plants rather than on edible plants.
Water can be treated to remove pathogens, just as one would treat stream water for drinking when backpacking, etc. However, chemical treatment methods would not eliminate chemical contaminants that might be present. It should also be noted that the parasite, Cryptosporidium, is tolerant to chlorine so treatment of water with chlorine alone may not be effective in eliminating this organism if it is present. Filtration in addition to chlorine treatment is used to ensure safety of municipal drinking water. Plain, unscented, concentrated household bleach with 8.25% hypochlorite can be added at the rate of 1/8 teaspoon for every 2 gallons of water. A 55 gallon rain barrel would need approximately 3.5 teaspoons of this bleach. However, the frequency for treatment may vary depending on how much rain is received. For more information, see https://www.clorox.com/dr-laundry/disaster-preparedness-purifying-water/ and https://www.epa.gov/ground-water-and-drinking-water/emergency-disinfection-drinking-water. To avoid guesswork where food safety is concerned, especially in school and community gardens, it is best to use collected rainwater for ornamental plants rather than on edible plants.
- What about composted cow manure sold in bags at a garden center?
When purchasing manure for use on gardens containing edible plants, look for products labeled “composted” and “for use in vegetable gardens.” If using raw manure that is not composted or has been improperly composted, a waiting period between application of the raw manure and harvest of the crop should be observed. The National Organic Program uses waiting periods of 90 days between application of raw manure and harvest for produce that grows above the soil like corn and 120 days for products that touch or grow in the soil like carrots or melons. No waiting period is required if manure is properly composted. However, for school and community gardens, it is safest to avoid animal manure in compost.
- Also, is it good enough to use hand sanitizers instead of regular handwashing? If not, why?
Handwashing is the ideal way to clean hands. Research has shown that hand sanitizers are not as effective against viruses like norovirus, a leading cause of foodborne illness, as they are against bacteria. They are also not as effective if hands are dirty or greasy. However, if no handwashing is available, then hand sanitizers are better than no cleaning at all, keeping in mind that viruses may not be eliminated. Hand sanitizing wipes may be more effective than gel sanitizers because the friction of rubbing may help to remove germs. If hand sanitizers are to be used, they should be at least 60% alcohol. Follow package directions for use regarding contact time.
- Can you clean with tea towels or dish towels instead of using paper towels?
Yes, clean cloth towels can be used.
- What is the recommendation for treating rain barrel water per 55 gal drum?
(SEE ANSWER 7)
- If kids are taking food home from the garden, what should they be placed in (what kind of container?)
New, single use paper bags such as lunch bags; new cardboard boxes; green molded pulp baskets for use with produce; single use plastic clamshells, or plastic containers that can be washed and sanitized between uses are all good options for use with produce.
- Are there soil tests for harmful bacteria? What can be used to kill harmful microbes in rain barrels?
Yes there are methods to test soil for foodborne pathogens. Typically this is not done on a routine basis unless there is reason to believe that the soil may be heavily contaminated. Questions that should be asked before testing the soil should focus on the likelihood that the soil is highly contaminated with animal waste or sewage (e.g., whether or not uncomposted manure or sewage has been applied to the area, whether or not animals frequent the area, etc.). If the likelihood is not great, then soil testing is probably not needed. If there is a great likelihood that the growing soil could be contaminated, then the proper approach would start with preventing the contamination or future contamination from occurring. If one still wants to test the soil, then proper microbiological methods should be used. There are documented methods in the scientific literature.
Rain Barrel Question – (SEE ANSWER 7)
- How do you treat water in rain barrels?
(SEE ANSWER 7)
- Since arsenic is no longer used for treated pine, what is the risk in using treated lumber for a raised bed? Has research determined that today’s treated lumber will be harmful?
(SEE ANSWER 1)
- Where would we find the new water testing guidelines regarding irrigating from a well or above ground water source?
For growers who must comply with the Produce Safety Rule under the Food Safety Modernization Act, information on the key requirements of the rule, including water requirements can be found at https://www.fda.gov/downloads/Food/GuidanceRegulation/FSMA/UCM472887.pdf. The Produce Safety Rule requirements do not apply to produce grown for personal consumption. Growers may also be exempt depending on the amount of produce they sell, the type of produce they grow and how the produce is sold. To learn more about who must comply with the rule and who is exempt, visit the website of the National Sustainable Agriculture Coalition to view decision trees for the Produce Safety Rule and the Preventive Controls for Human Foods Rule at https://sustainableagriculture.net/wp-content/uploads/2016/02/2016_2-FSMA-Final-Rule-Flowchart-V3.pdf.
- Is re-use of egg cartons from egg farms a wise practice?
The Egg Safety Center recommends discarding egg cartons and not reusing them.
- Is washing hands with cold water and soap effective as hot water? So many restaurants, stores, and other facilities only have cold water.
According to the Centers for Disease Control and Prevention, warm or cold water can be used to wash hands. However, warm water may be more effective at removing grease from hands. The Food and Drug Administration’s 2013 Food Code for retail food establishments specifies employees should wash their hands and forearms before handling food for at least 20 seconds in warm, running water from a handwashing sink.
Retail food establishments should have a dedicated handwashing sink in the food preparation area where employees wash hands before food handling. Employees should not wash hands in sinks used for dishware washing, produce washing, or in sinks used for mopping, etc.
If water in the restrooms is cold, it does not necessarily mean that the water in the food preparation area where a handwashing sink should be located is also cold. However, this might be a question for the management!
You can learn more about the FDA 2013 Food Code at https://www.fda.gov/downloads/Food/GuidanceRegulation/RetailFoodProtection/FoodCode/UCM374510.pdf.
- Where can we find examples of written rules?
Until the Produce Safety Rule that is part of the Food Safety Modernization Act went into effect, there has not been a nationwide standard for growing, harvesting, packing, storing and transporting produce. Larger growers and growers selling through distributors generally followed the National GAP Program guidelines (GAP) and participated in a third party audit process to enhance food safety and as a way of protecting their businesses from liability issues. The National GAP Program materials are currently unavailable and will be updated to reflect changes under the Produce Safety Rule. Our UGA Enhancing the Safety of Locally Grown Produce materials will also be revised to include specifications that growers will need to meet if their business expands to the point where compliance with the Produce Safety Rule is required.
However, if you are growing and selling produce or giving produce to charities, etc., it is important to make sure the food is as safe as possible. Regardless of size, it is important to follow best practices to enhance food safety. For growers who must comply with the Produce Safety Rule under the Food Safety Modernization Act, information on the key requirements of the rule, including water requirements can be found at https://www.fda.gov/downloads/Food/GuidanceRegulation/FSMA/UCM472887.pdf.
An excellent publication on Food Safety for Gardens is available at https://growingsafergardens.files.wordpress.com/2012/10/foodsafetywebcurriculum-10-24-12.pdf.
Minimal guidelines for marketing safe foods at farmers markets are included in the following publications.
https://agr.georgia.gov/Data/Sites/1/media/ag_marketing/The-Farmers-Market-Guide.pdf
https://www.carolinafarmstewards.org/wp-content/uploads/2013/07/CFSA_GAPS-web.pdf
It should also be noted that individual market boards and market managers need to have established food safety rules for their markets. Individual markets can have rules that are even more stringent or strict than state department guidelines. More information about safe growing and handling of produce and safety in farmers markets will be presented to UGA Master Gardeners at the August 2017 training.
- Farmers Markets reuse baskets – who monitors this?
Inspectors from State Departments of Agriculture visit and inspect farmers markets. Traditionally, they have focused on meats, dairy and eggs that are being sold in these markets, and not on fresh, whole produce. Reusing baskets that cannot be washed and sanitized and reusing cardboard boxes can be a potential source of contamination and cross-contamination for fresh produce and should be avoided. It is the responsibility of the gardener/grower to use the best practices possible to ensure the safety of the food they produce and sell or give away, even if no one monitors the practices. Local farmers and gardeners like to market their produce as being safer and healthier than what can be found in the stores and so should use best practices to enhance safety of their products.
- Is it best to use a tin tub, aluminum pan or a plastic storage bin to rinse the harvest from the garden?
When rinsing fruits and vegetables harvested from the garden, it is best to rinse them under running water and in a container that allows the water to drain away from the produce, thus carrying soil and contaminants away from the product rather than allowing the produce to sit in water that has become unclean. This would help to prevent contaminants from entering into the produce through stem scars, openings or damaged areas. The container needs to be one that can be easily and repeatedly cleaned and sanitized between uses.
- Treat rain barrel water with what before using it on edible plants?
(SEE ANSWER 7)
- Any protocol for people who smoke/use tobacco products in gardens and greenhouses?
Guidelines for working with produce or any other food say that there should be no eating, drinking, smoking, use of tobacco products or chewing gum when working with food. It should be no different in gardens or greenhouses. Whenever people eat, smoke, etc. their hands go to their mouths which can be a source of contamination. In addition, cigarette butts, ashes, chewing gum, etc. can fall into or onto products or can be left behind as a source of contamination in the garden. It is not a sanitary situation.
- Can you use animal manure on your Hugelkultur garden?
According to several publications from other states on Hugelkultur, manure can be added. However, to enhance produce safety, use only manure that has been properly composted before adding to this type of gardening bed structure. If these techniques are used in school and community gardens, avoid the use of animal manure.
- What about the use of tobacco products in and around gardens?
(SEE ANSWER 23)
- What about a legionnaire’s outbreak?
Legionnaires Disease is a severe type of pneumonia caused by breathing in droplets of moisture contaminated with the bacterium, Legionella. It is not a foodborne illness. In an outbreak of Legionnaires Disease in Louisiana in the late 1980s, four people who had come down with the illness had shopped at the same grocery store and the disease was linked to misters used at that time. Since that time, a family in the state of Washington speculated that grocery store misters caused a family member to have the disease. However no epidemiological link was established in the case. Since the outbreak in the 1980’s, there have been improvements and modifications in the design of misting systems for produce misting.
There are on average about 5,000 cases of Legionnaires Disease in the U. S. each year. The Centers for Disease Control and Prevention list the most common sources of this disease as cooling towers that are associated with air conditioning systems of large buildings, hot tubs, water used for showering and decorative fountains. Breathing in the aerosolized bacteria is the mechanism of infection.
- How effective are the vegetable wash products that you buy at the grocery store?
If produce is contaminated with disease-causing organisms, and especially if the contamination is inside the fruit or vegetable, vegetable wash products are unlikely to eliminate the problem. The U.S. Food and Drug Administration recommendations for consumers state:
“when preparing any fresh produce, begin with clean hands. Wash hands for at least 20 seconds with soap and warm water before and after preparation. Wash all produce thoroughly under running water before preparing and/or eating, including produce grown at home or bought from a grocery store or farmers’ market. Washing fruits and vegetables with soap, detergent, or commercial produce wash is not recommended.”
Judy A. Harrison, Ph.D.
Professor and Extension Food Safety Specialist
Dept. of Foods and Nutrition
College of Family and Consumer Sciences
University of Georgia
3/2017
