Last week, for example, the Centers for Disease Control and Prevention (CDC) reported that an outbreak of Salmonella that has sickened 39 people in 15 states and is linked to handling poultry. Nine of those individuals were so sick they required hospitalization. The contaminated chicks and ducklings causing the outbreak have been traced to a mail-order hatchery.

Although it is difficult to determine just how many people have made the switch to home-raised chickens, as of March 2010, more than 50,000 chicken owners were subscribing to the forum BackyardChickens.com.

“I think everybody should have chickens,” said Brad Henderson, a permaculture farmer in Bishop, CA., whose family has raised chickens since he was two years old. “They perform so many services and they don’t require much in return. Of any animal on the planet, you can’t do much better than chickens.”

Henderson said that not only do backyard chickens provide a nutrient-rich source of food, but they can also serve as low-maintenance composters, waste recyclers and weed eaters. Amy Henderson, who has been raising backyard chickens with her husband for almost 13 years, said that backyard, free-range chicken eggs also taste noticeably better than store-bought eggs. She said when chickens have the space to graze on grass and eat insects, the color of the yolk turns a bright orange, which is indicative of a healthy diet. Most store-bought eggs, she said, don’t come close to matching the color of healthy egg yolks.

“If we don’t have access to our own eggs, we don’t even bother to buy them,” she said.

A 2005 study conducted by Mother Earth News showed that, on average, true free-range eggs contain lower cholesterol, higher omega-3 fatty acids, and lower saturated fats than factory farm eggs. In the study, “free-range” did not include farms that simply left a small door open for chickens to go in and out, or farms that did not provide sufficient range land. Brad Henderson said that sometimes, “free-range” means that chickens only have access to a concrete patio.

But, while backyard, free-range chickens may lay more nutritious eggs, they are still susceptible to transmitting diseases like Salmonella.

Most types of Salmonella grow in the intestinal tracts of animals and birds. Humans can become infected with the pathogen after eating foods that come in direct or indirect contact with animal feces, according to a July 2010 Centers for Disease Control and Prevention (CDC) report. A common problem used to be that chicken feces on the outside of a shell would contaminate the egg once the egg was cracked. But now, according to the CDC report, Salmonella illnesses from factory farm egg shells are less frequent, since industry standards for cleaning and inspecting became more rigid in the 1970s.

Thoroughly cleaning eggs can also have the opposite effect, though. Washing an egg can remove the protective “bloom” that prevents bacteria from entering eggs. The bloom is the gelatinous outer layer that dries after a hen lays an egg, sealing pores on the shell to help block bacterial infection, according to a report written by Diane Schivera, an organic livestock specialist for the Maine Organic Farmers and Gardeners Association.

Amy Henderson said her family does not wash their eggs, and only spot-cleans them if specks of dirt are present.

The current commercial operation standards for cleaning eggs removes the protective bloom, thus making infection from feces less common, but by consequence, increases the likelihood of bacterial infection. If a batch of cleaned eggs is exposed to an infected egg, the whole batch will often become infected, according to the CDC web site.

If chicken owners prefer to wash eggs, Schivera suggests using water that is at least 90 degrees Fahrenheit, which will make the egg contents expand, pushing dirt away from the shell’s pores. For dirtier eggs, people can roll the eggs around in a sanitizer (½ oz. of chlorine to 1 gallon of water) in a colander, without submerging the eggs or letting them sit in the sanitizer. If the temperature of the eggs and the sanitizer equalize, an egg’s membrane can absorb contaminants from the water. Soon after washing, eggs should be cooled, dried and stored at 45 degree F. According to Schivera’s report, room temperature can make eggs drop as much as one grade per day.

As an egg ages, protective barriers inside the egg break down and the egg becomes more susceptible to bacteria, according to Schivera’s report. The egg white’s alkalinity discourages bacterial growth and the thick white inhibits movement of bacteria. When the white weakens with age, bacteria are more able to enter the nutrient-rich yolk, where they can thrive if the egg is stored at a warm temperature. However, a clean, fresh egg is rarely internally contaminated.

Since the 1980s though, incidents of Salmonella caused by intact grade-A eggs with spotless shells have been on the rise. The reason is that the bacteria can infect the ovaries of a chicken and contaminate an egg’s innards before the shell is formed.

Last August, a half-billion eggs were recalled after a nationwide Salmonella outbreak investigation that linked over 1,500 illnesses to Iowa’s Hillandale Farms and Wright County Egg. According to news reports, researchers sourced the outbreak to the strain of Salmonella produced in a chicken’s ovaries that forms inside the egg.

The 2010 CDC report estimated that one in 20,000 eggs is internally contaminated. A healthy-looking hen might be infected with Salmonella, and may lay an occasional SE-contaminated egg while the rest are safe for human consumption. This is true for both factory-farm and backyard chickens. However, the probable risk of infection is extremely small. According to the American Egg Board’s Egg Safety reference, an average consumer might encounter a contaminated egg once every 84 years.

Salmonella infection can cause fever, abdominal cramps, and diarrhea 12 to 72 hours after eating a contaminated egg. Symptoms can last four to seven days and most people recover without antibiotic treatment, although severe diarrhea may necessitate hospitalization, according to the CDC Web site.

In his lifetime of chicken-raising, Brad Henderson said he has never gotten Salmonella. Currently, the Hendersons own 42 hens and refrigerate all their eggs. The couple has two young daughters and no one in their family has ever contracted Salmonella. 

When raising chickens at home, keeping flocks healthy and taking certain safety precautions is the best way to prevent against Salmonella transmission, the Hendersons said.

Brad Henderson said buying chicks from a reputable hatchery is the first step. Hatcheries that produce a variety of heirloom breeds are often a good choice, because chicken diversity can benefit a flock’s health.

After that, Henderson said, keeping chickens healthy requires that they have ample sp
ace to roam, access to gra
ss and insects, and a place to take dust baths. To get rid of mites, chickens will find patches of dust or dirt to bathe in, which suffocates any mites. The Hendersons said that keeping the coop clean, changing food and water daily, and providing good ventilation are also essential to chicken health. Providing protection from animals like eagles, raccoons or foxes will also keep chickens safe from predation and contracting disease.

Brad Henderson said there is some risk of pathogen contamination if fresh chicken manure is put directly on food gardens. However, if given enough sun, heat and time, chicken manure that goes through the composting process will be stripped of any harmful bacteria. Chicken manure should be cured for 45-60 days before adding it to a vegetable bed, according to a report compiled by Judy Duncan, King County Master Gardener and WSU Cooperative Extension livestock advisor (http://seattletilth.org/learn/resources-1/city-chickens/compostingchickenmanure). During the curing process, no more chicken manure should be added. Since chicken manure is so nitrogen-rich, the compost heats up more quickly, killing any harmful bacteria in a shorter amount of time than most other types of manures, said Sheri Hinshaw, environmental educator for the Seattle Tilth Garden Hotline.

“When you add compost to your garden it should be dark, crumbly, and sweet-smelling,” Hinshaw said. “But Salmonella is very rare in composted chicken manure.”

According to Duncan’s report, fresh chicken manure has the highest chance of contaminating crops such as carrots, radishes, beets, lettuce and spinach. However, appropriately composting the manure should kill any potentially harmful bacteria. A compost temperature gauge can be purchased to see if the compost is between 130-150 degrees Fahrenheit, which is the temperature required to kill harmful bacteria. However, if a temperature gauge isn’t handy, then letting the compost cure for 45-60 days will do the trick.

People who are especially at risk if exposed to Salmonella should avoid eating uncooked vegetables from gardens that use any type of manure. These at-risk groups include pregnant women, young children, and people with chronic diseases. Chicken manure can also be used without risk of food-contamination by adding it to a flower garden instead.

The CDC also recommends certain Salmonella-prevention strategies for people taking chicken production into their own hands (and yards). Precautions include disinfecting hands, clothes, shoes and equipment before and after handling chickens; discarding cracked eggs; and washing hands, cutting boards, dishes, utensils, and countertops with soap and water after contact with raw eggs. Also, thoroughly cooking eggs until both the yolk and white are firm can reduce the risk of Salmonella infection, but sometimes cannot completely destroy Salmonella contamination.

Brad Henderson said that by raising his own chickens, he is less worried about Salmonella than if he were to buy eggs from the store. He said that after learning how factory farm chickens are treated — breathing in fecal dust all day in an overcrowded environment, and getting pumped full of antibiotics — he is even more convinced that raising his own chickens is the way to go. He said in commercial operations, chickens are killed after one year, due to stress overload. Some of his family’s chickens, though, will be 10 years old this year.

“Here, we keep them for their whole natural lives,” Henderson said. “We are on the chicken retirement plan.”

While the risk is relative — it could be more dangerous to drive on a holiday weekend, for example — there are easy ways to reduce exposure to carcinogens when cooking outdoors. Plus it’s good to know the science involved in high-heat cooking.

When meats are grilled, broiled, or seared, the high cooking temperature breaks down the amino acid creatine (an amino acid found in muscle), forming chemicals called heterocyclic amines (HCAs). The federal government added HCAs to its list of known carcinogens in 2005. Some of the highest concentrations of HCAs are found in grilled meats, according to a 2003 study published in the International Journal of Food Science and Technology. Grilling meat provides the right conditions for HCA formation because more HCAs are produced the longer and hotter the meat cooks.

Since HCAs are mutagens, they can bind directly to DNA, causing the kind of mutation that can promote formation of cancerous cells. Studies have linked frequent ingestion of HCAs to an increased risk of pancreatic and colorectal cancers. Regularly eating charred, well-done meat may increase the risk of pancreatic cancer by 60 percent, according to a University of Minnesota study, so scrape off any charred bits before serving.

“There is some evidence that consuming red meat — whether it’s grilled or not — increases the risk of colorectal cancer,” said Bonnie Liebman, director of nutrition for the Center for Science in the Public Interest.

Liebman cited a National Institutes of Health (NIH) study that tracked the meat consumption of half a million members of the AARP (American Association of Retired Persons) over 10 years. The study found that people who ate five ounces of red meat a day (about 1.5 Quarter Pounders) had a 30 percent higher risk of dying of cancer. Conversely, those who consumed an average of two-thirds of an ounce per week were on the low end of the risk spectrum.

Prior to the NIH-AARP study, Swedish researchers examined 15 studies and found that red-meat eaters have a 28 percent higher risk of colorectal cancer than those who eat little or no red meat.

Although chicken and fish have long been regarded as healthier alternatives to beef and pork, the grilled versions of these meats pose increased or comparable risks of HCA exposure. Grilled chicken produces 10 times more HCAs than those recorded in grilled beef, according to a Cancer Project study, sponsored by the Physicians Committee for Responsible Medicine. In grilled chicken, practically all the detected HCAs were in the form of PhIP, one of the carcinogens linked to an increased risk of breast cancer.

According to the Cancer Project study, the top five grilled meats recorded with the highest concentrations of HCAs (in order of highest concentration to lowest) are chicken breast, steak, pork, salmon and hamburger. Fish usually contains high levels of creatine, the amino acid responsible for increased production of carcinogens. For this reason, grilled salmon produces more HCAs than grilled hamburger meat, according to the Cancer Project study.

Grilling meat can also produce other types of food mutagens such as polycyclic aromatic hydrocarbons (PAHs), according to the Agency for Toxic Substances and Disease Registry. When grilling or broiling meat, the fat can drip into the open fire or electric heating element, which produces smoke and flames containing PAHs. The PAHs then bind to the surface of the meat, forming higher concentrations of PAHs the longer and hotter the meat is cooked. Choosing lean cuts instead of high-fat varieties, plus trimming fats and removing the skin from salmon and poultry is recommended.

Studies have linked the frequent consumption of grilled and broiled meat to the development of stomach cancer, according to the American Institute of Cancer Research. Liebman said that while these studies do show strong correlation between grilled meat and increased cancer risk, correlation can’t determine causation. Conducting these studies is not an exact science.

“You can’t say that these studies show that your risk of cancer will definitely increase if you eat grilled meat,” Liebman said.

For example, she said, in the NIH-AARP study, the researchers tried to control for as many variables as possible, such as weight, education, smoking, and vitamin intake. However, it’s hard to determine whether red-meat eaters have a higher cancer risk because they eat red meat or because the healthy lifestyle choices generally differ between those who frequently eat red meat and those who eat less or none at all, she said.

To reduce the risk of cancer, meat-lovers need not forego grilling altogether. Instead, avoiding the blackened or burned parts of meat can lower the risk of exposure to HCAs. Obviously, eating grilled meat less frequently and eating smaller portions of grilled meats will also reduce the risk of cancer.

Frequently flipping meat helps, Lieberman said. Cooking meat six minutes on both sides instead of 10 minutes on one side can cut HCAs by 70 percent by keeping the surface temperature lower, she said. Because piercing meat with a fork can cause drips and flare ups, use tongs or a spatula instead.

Cooking meat in a microwave for one to two minutes and pouring off the juices can remove 90 percent of the HCAs. However, Lieberman said, this often leaves the meat dry and not as appetizing. Marinating meat can also significantly reduce the production of HCAs. A tip sheet from Purdue University suggests marinades that contain anti-oxidants (vinegar, citrus juices, herbs, spices and olive oils) will help inhibit the formation of carcinogens on grilled meat.

Keeping the meat moist generates fewer HCAs. Boiling, steaming, poaching or stewing meat does not form HCAs because the temperature of the meat cannot increase past the boiling point.

Grilling non-meat alternatives is usually a safe bet against exposure to HCAs, because the formation of HCAs depends on the presence of creatine, which is mostly found in muscle tissue. Studies show that grilling vegetables, fruits and soy products do not yield HCAs, or only produce levels too insignificant to pose a health threat. Certain vegetables like broccoli and Brussels sprouts may help detoxify the liver of HCAs. Grilled alternatives to meat include portabella mushrooms, veggie burgers, fruit like pineapple, and kabobs that are light on the meat and heavy on the vegetables.

“Eating grilled meat once in a while probably isn’t going to do much harm,” Lieberman said. “But there are those people have the easy-to-use backyard grills who are grilling every other night. For them, the risk might be higher.”