Life Outside the City Limits
By Steve Tonn, Nebraska Extension Livestock Educator
March can be a month with extreme changes in the weather which can put stress on animals. Livestock owners must observe animals closely to keep individual animals and the whole herd or flock healthy and productive. If the health status of a herd is compromised, that operation will not be as efficient as possible.
To recognize clinical signs of diseases common to livestock, it is important to be familiar with what is normal or healthy. Livestock owners should assess the herd or flock’s general health, on a regular basis, including vital signs, body condition and coat.
Signs that Indicate Healthy and Unhealthy Animals
|Healthy Livestock:||Unhealthy Livestock:|
|Chewing cud||Ruminants not chewing their cud|
|Sleek coat||Rough hair coat|
|Bright eyes and pink eye membrane||Dull eyes|
|Normal feces and urine||Abnormal feces and discolored urine|
|Normal temperature||High temperature|
|Steady, no limping||Limping|
|Normal respiration||Labored breathing/coughing|
|Stays in herd or flock||Separates self from herd or flock|
|Eats and drinks normally||Loss of appetite|
|Normal pulse rate||Swelling on any body part|
If the animal’s condition call is not familiar to the owner or one they cannot treat, it is advised to contact a veterinarian for help. Local veterinarians will be able to diagnose the problem and prescribe the proper treatment.
Resources to explore:
Common Diseases and Health Problems in Sheep and Goats, Purdue Extension
You have probably heard about elevated lead levels in Flint, Michigan’s drinking water and you may be wondering if you could have lead in your private well water.
Sources of Lead in Drinking Water
In most situations, including Flint, lead contamination takes place at some point in the water delivery system. This occurs as a result of corrosion, the reaction between the drinking water and lead that has been used to construct parts of the water delivery system. Did you know that lead in drinking water from plumbing or fixtures is most often a problem in either very old or very new homes and buildings? It’s true, but any home or building may be susceptible.
Through the early 1900s it was common in some areas of the country to use lead pipes for interior plumbing. Lead piping is most likely found in homes and buildings built before 1930. Copper piping replaced lead piping, but lead-based solder was used to join copper piping. It is likely lead-based solder was used in any home built before 1988.
Today, brass materials are used in nearly 100 percent of all home water distribution systems. Many household faucets, plumbing fittings, check valves and well pumps are manufactured with brass parts. Brass contains some lead to make casting easier and the machining process more efficient. As of January 2014, federal regulations allow no more than 0.25 percent lead content of brass plumbing components labeled “lead free.” “Lead free” brass components manufactured before that date could have as much as 8.0 percent lead content.
Some private wells may have submersible pumps containing brass or bronze capable of leaching lead. Some well screens also may contain lead or were installed with a “lead packing collar.” Potential lead contamination also exists if the well is a driven, sandpoint well and has been “shot” to clear the screen. Lead shot was sometimes poured into a well to keep out sand. In other wells, lead wool was used. While these were acceptable practices at the time, none of these practices are recommended, and sandpoint wells driven into the ground are not approved for drinking water purposes under Nebraska well construction regulations.
How Does Water Quality Affect Lead Contanimation?
The characteristics of water vary greatly depending on the source of the water. Some water is naturally more corrosive and will be more likely to dissolve lead. Several factors cause water to be corrosive including low pH (pH less than 8.0), high temperature, low total dissolved solids (TDS) content and high amounts of dissolved oxygen or carbon dioxide. Generally, naturally soft water is more corrosive than hard water because it is more acidic and has low TDS. Treating naturally hard water with an ion exchange water softening unit, reverse osmosis unit, or distillation unit may change the water chemistry significantly enough to have an effect on the water’s ability to dissolve lead.
Often, hard water minerals deposit on the interior of plumbing. These deposits form a mineral scale lining, such as calcium carbonate, inside pipes and fittings, which protects against lead contamination. It may take up to five years for an effective mineral scale lining to form. Treating naturally hard water with an ion exchange water softening unit, reverse osmosis unit, or distillation unit can either prevent or dissolve the scale, eliminating its possible protective effect.
Water Testing for Lead
If you want to know if lead is present in your private drinking water supply, you will need to have the water tested. Although private water supplies are not subject to any regulations concerning lead contamination, you may want to test your water supply, especially if lead is suspected or if children or pregnant women consume the drinking water.
Tests to determine the presence of lead in drinking water should be done by a laboratory approved for lead testing. The Nebraska Department of Health and Human Services approves laboratories to conduct tests for drinking water supplies.
To determine if lead is present in a private drinking water supply and to determine the possible source of the contamination, water must be tested using specific sampling procedures. Carefully follow all directions provided by the laboratory and use provided containers when collecting water samples.
In general, water that comes in contact with lead in the plumbing will continue to dissolve lead over time. For this reason, the highest lead concentration in drinking water will result from water that has sat motionless in the plumbing system, in contact with lead-containing components, for an extended period of time (e.g., several hours or overnight). To evaluate the highest lead concentration, collect a sample of the water that has sat motionless in the plumbing system, in contact with suspected lead-containing components for six or more hours. This is sometimes called a “first-draw” sample.
The length of time the tap should be run prior to collecting the water sample will depend on where the suspected lead-containing components are located in relation to the tap being used. Collect the very first water drawn if suspected lead-containing components are close to the tap. Collect water drawn after the tap was run for a few seconds to a minute or two if suspected lead-containing components are present in the water delivery system farther away from the tap (e.g., in pipes, well pumps, etc.). Try to time the water collection process to obtain a sample representative of the highest contamination. If it is not known if or where lead-containing components might be located, collect the first water drawn. If there is a great concern, you can collect multiple samples from the tap that span a time frame from first water drawn to water that takes a few minutes to pass through the system.
EPA Lead Guidelines
Environmental Protection Agency regulations for public water supplies, and Nebraska regulations do not apply to private drinking water wells. However, you may consider the EPA established action level of 15 parts per billion as a guideline in assessing the risk associated with your water supply. If lead concentrations are found to be above 15 ppb, you might voluntarily consider EPA guidelines, and try to reduce the lead concentration in the water, taking into account health risks, costs, and benefits.
Minimizing Lead in Your Drinking Water
If water tests indicate lead is present in drinking water and testing determines the source is household plumbing, you should first try to identify and eliminate the lead source. If it is neither possible nor cost-effective to eliminate the lead source, flushing the water system before using the water for drinking or cooking may be an option.
Flushing the system involves disposing the water that has sat motionless in the plumbing system, in contact with lead-containing components, for an extended period of time. Anytime the water has not been used for several hours, the water should be run until it becomes as cold as it will get. This could take as little as thirty seconds or longer than five minutes depending on the system. Each faucet must be flushed individually before using the water for drinking or cooking. Water run from the tap during flushing can be used for non-consumption purposes such as watering plants, washing dishes or clothes, or cleaning.
In addition, you should avoid cooking with or consuming water from hot-water taps. Hot water dissolves lead more readily than cold water. Especially avoid using water from a hot water tap for making baby formula.
Several treatment methods are suitable for removing lead from drinking water, including reverse osmosis, distillation, and carbon filters specially designed to remove lead. Typically these methods are used to treat water at only one faucet. Reverse osmosis units can remove approximately 85 percent of the lead from water. Distillation can remove approximately 99 percent. Simply boiling water does not remove lead. A water softener can be used to pretreat water for either a reverse osmosis or distillation unit when water is excessively hard. Low flow rates are required when using lead selective carbon filters. Typically they have flow controllers which limit the system to 0.25 to 0.5 gallons per minute.
In summary, lead rarely occurs naturally in drinking water. It is more common for lead contamination to occur at some point in the water delivery system. To determine the presence of lead in drinking water and its possible source, a specific procedure must be used to collect samples and a certified laboratory should be used for testing. Management of a private drinking water well for lead is a decision made by the well owner and/or water user. A water test is the only way to determine the lead concentration. If drinking water exceeds the EPA lead standard of 15 ppb, steps can be taken voluntarily to reduce the risk. Options include removing the lead source, managing the water supply used for drinking and cooking by flushing water with high lead concentrations from the water system, using water treatment equipment, or using an alternative water source. Options selected must be based on the specific situation.
For more information see the Nebraska Extension NebGuide “Drinking Water: Lead.”
By Kelly Feehan, Nebraska Extension Educator - Horticulture
Tree planting season will soon arrive. Trees are a long term investment that benefit property values, community vitality, and the environment. And they are simply nice to be around.
What Is A Quality Tree?
Make a wise investment by selecting a quality tree to plant. There are quality trees and then there are trees that grow very fast and have brittle wood; or trees that have major pest or other issues.
A quality tree would be one with strong structure. For example, a tree that does not have a narrow, upright branching pattern that makes it susceptible to storm damage. Or trees that tend to have co-dominate leaders.
Quality trees also have stronger wood which is often determined by growth rate. Trees labeled as having medium to slow growth typically have stronger wood. But don’t let this description mislead you. These trees, planted in the right location, often grow faster than expected.
A quality tree also requires fewer inputs of pesticides, iron, or more. It is a tree that is adapted to the sites growing conditions such as soil type, winter hardiness, and heat hardiness.
Tree Selection Considerations
By now you might be thinking why not just list some examples of quality trees. I will provide a list but there are many good trees. Selecting the right tree for the site depends on the growing conditions of the site and the tree owner’s personal likes and dislikes.
Before selecting a tree, know the growing environment of the site. What is the soil type? Is the soil well drained? Is the site exposed to high winds? Is it an irrigated lawn that remains too wet for healthy roots?
Know the physical characteristics of the site. How tall and wide of a tree is needed? Are there highline wires nearby? Where is shade needed? Is there a view that should be blocked or left open?
A quality tree is a tree the owner likes. I often tell people there is no perfect tree. Trees have good and bad points but what’s good and what’s bad is often in the eye of the beholder.
I suggest starting with a list of quality trees of the correct size that are adapted to the sites growing conditions. Then make sure you can live with any characteristics you perceive to be bad points.
Trees to Avoid
I also provide a list of trees to avoid planting, such as fast growing trees. These trees have softer wood that is often brittle and more susceptible to ice and wind damage. Some examples are silver maple, Austree, willows, Tree of Heaven, and Poplars.
Avoid selecting a tree susceptible to iron or manganese chlorosis. These are trees whose leaves turn yellow because the iron or manganese that is in the soil is not available due to our alkaline soils.
While these trees can be treated, why select a tree known to have a problem? And eventually, the often used injection method will shorten the trees life. Examples of trees that can become chlorotic are pin oak, swamp white oak, red maple, silver maple and ornamental pear.
Avoid trees known to have serious disease or insect issues. Examples of these trees are Scotch pine, European white birch and any type of ash. It is also wise to avoid trees that are overplanted. Even if they do not have a pest problem now, they likely will sooner or later due to monoculture.
Now for that list of trees to plant. These are quality trees as far as structure, few serious pest problems, and not being overplanted. If they work for you and your site, go ahead and plant one or more. If none of these work for you, ask a local nursery for suggestions of other quality trees.
Some of my favorites include ginkgo, white oak, red oak, Miyabe maple, Ohio buckeye, Kentucky coffeetree, and American hophornbeam. Others that I like are hybrid elms, bur oak, Japanese tree lilac, northern catalpa, American sycamore, and hardy nut trees like pecan and hickory.
Street trees face some tough challenges. They might best be compared to contestants on reality shows like “Survivor” where an average American, happy in the life they lead, is plucked out of a life of comfort, companionship and opportunity. For our viewing pleasure they are moved to a deserted island, along with a handful of strangers, and forced to scrape out an existence far away from the civilization they are accustomed to.
In a similar manner, urban trees also are taken away from their usual circumstances and placed in an unfamiliar and challenging environment. Recent studies have been undertaken with the hope that understanding that disparity, and incorporating as much of their natural habitat as possible in this new environment, might help us more successfully integrate trees into heavily populated areas.
Last summer the city of Omaha evaluated some of the factors affecting the health and longevity of street trees. Not surprisingly, surrounding buildings and roads have a huge impact on trees. The heavy equipment needed for hardscaping compresses soil and cuts the space for air and water infiltration in half. This compaction limits tree root growth and suppresses the buildup of organic matter. Add a few other stress factors, like de-icing salts, reflected heat and poor air quality, and it’s obvious how different these street corridors are from the forests where these trees originated.
Curbs, driveways and street medians are particularly challenging for trees, and therefore ideal places to experiment with the different factors in these settings. In the Omaha study, trees surrounded by concrete on all sides were half as likely to be in “excellent” or “good” condition as those with pavement on just one side. Those surrounded by turfgrass, and subject to damage from mowers and weed-whackers, were far less healthy than those surrounded by mulch or plants that don’t require mowing or trimming. Supplemental drip irrigation and higher organic matter also greatly improved health and the possibility of long-term health.
Another site category referred to as legacy plantings—undisturbed settings with a diversity of trees at different stages of maturity—proved even healthier. Though damage from mowing equipment was still fairly common, the improved soil quality and existing canopy cover made a difference. The slower and more deliberate pace of planting by volunteer groups could further explain why the trees were less likely to be planted too deep than in traditional plantings by contractors.
The study confirmed one of our assumptions about tree health in urban settings: that the further trees are taken from the context in which they are found, the more difficult it is for them to establish and thrive.
Trees do much more than provide character and a sense of place. They store carbon, remove pollutants, provide energy savings winter and summer and absorb and filter noise, stormwater and air pollution. These are tangible, real-world benefits that are worth protecting and improving as we plant trees in difficult urban settings.
The Nebraska Forest Service strives to enrich lives by protecting, restoring and utilizing Nebraska's tree and forest resources.
“One of the things I learned to do as a young gardener was look at plants bit by bit, to see if there was anything that delighted me. Never mind what the plant is famous or infamous for. Look, and see for yourself.... It is the spectrum, not the color, that makes color worth having, and it is the cycle, not the instant, that makes the day worth living.” Henry Mitchell
Where winters are long and cold and colors are faded by sun, wind and snow, the first glimpse of green growth is long awaited. The emerging tips of perennials aren’t very noticeable from a distance, and even on close inspection may be just barely evident. But they’re a promise of green to come.
Rather than being impatient for what’s ahead, it’s a good time to push away some leaves or snow and look for signs of spring. What might you find?
Plants like coralbells, lambs’ ear, Lenten rose, columbine, bergenia and many of the penstemons stay somewhat green all winter, particularly in protected spots. Groundcovers like periwinkle never fade and even bloom early in spring, along with other low-lying plants like lungwort and candytuft.
Perennials that have died back may start pushing through the soil in late February or early March. Have you ever noticed the deep red tips of peonies in late winter? By early or mid-March, garden phlox, Oriental poppy, lady’s mantle, daylily, evening primrose and many spring bulbs are visible. The emerging spears of Solomon’s seal are edible and look and taste very much like asparagus; and they can be eaten in the same ways—fresh, steamed or roasted. New shoots should emerge from the base, but don’t cut too many from any given patch.
Some perennials, including bergenia, prairie smoke and columbine, turn dark red or purple in fall and emerge in these dark colors again in spring; colors that may not stand out against soil or mulch, but surrounded by snow they’re a welcome sight in the winter garden.
Early-blooming prairie wildflowers include pasque flower and prairie smoke, and both are far more than one-season plants. Pasque has beautiful, feathery seedheads and prairie smoke has purplish foliage fall through winter. Pussytoes remain silvery green all winter and flax (Linum) puts on fragile-looking new growth in fall that stands tough through snow, wind and ice. Contrary to the delicate appearance of these prairie plants, they’ll outlast any harsh weather winter throws at them.
Blooms will come soon enough and early-to-rise usually means early to bloom as well, so these plants and others—columbine, bleeding heart, celandine poppy, bluebells, Jacob’s ladder—will soon offer bright blossoms. But for now, if we look closely, there is promise enough of the green to come. More information and photos at Nebraska Statewide Arboretum, Pinterest - Spring Blooming Perennials.
Nebraska Statewide Arboretum is a nonprofit that works toward sustainable home and community landscapes through initiatives in education, public gardens and the environment. Plant and landscape resources at http://arboretum.unl.edu.
By John Fech, Nebraska Extension Educator - Horticulture
The previous owners of your home may not have planned well. You misread the tag on the plants at the nursery. You wanted immediate results and installed shrubs very closely. Whatever the reason, now you have overgrown shrubs. This is a common scenario in the landscape. When faced with this situation, you have three options: 1. Remove some shrubs completely, 2. Thin and shape the shrubs, or 3. Cut them back severely.
The easiest of the three options is to cut them back severely. The simple procedure involved is to cut each stem off at or an inch above the soil line. As the season progresses, dormant side buds will start growing, producing stems to replace those removed. With most species, by the end of the season, the shrub will have grown back to about half the height it was when you found it to be overgrown. Select only the strong, well-formed stems to remain in the shrub. If you leave weak or poorly angled stems, the overgrown scenario will return in just a few years.
The root systems of overgrown deciduous shrubs tend to be extensive, allowing the plant to rebound and regrow quickly as they are able to draw upon these roots for water and nutrients. Spirea, lilac, viburnum, cotoneaster, weigela, dogwood, mockorange, burning bush, chokeberry, buckthorn, hydrangea, hybiscus, coralberry and snowberry are shrubs that respond well to severe pruning in spring.
By Sarah Browning, Nebraska Extension Educator - Horticulture
Winter damage to trees is common, often caused by heavy snow or ice. Trees can be pruned to improve their strength and structural integrity, but another good strategy for minimizing damage it to choose trees less prone to damage.
Characteristics of Trees Prone to Storm Damage
Characteristics that make trees more prone to damage include 1) narrow branch angles with the main trunk, 2) included bark, 3) broad spreading crowns, 4) dead branches and 5) decayed wood.
Some trees naturally produce branches with narrow branch angles, which often makes the branches more likely to also develop included bark. Included bark occurs when bark is pinched between codominant branches, so there is no physical connection between them. Instead, at their base, is bark pressed against more bark. Often a trunk split will begin at this weak union point and once a split or crack begins to develop, it only gets worse over time. Trees commonly fail or split at the crack when the tree is under a heavy load from ice or snow.
Trees with broad spreading crowns are more likely to accumulate heavy snow or ice loads. Fast growing trees, like silver maple and cottonwood, are more likely to develop dead wood or decay in older trees, resulting in weakened branches unable to withstand heavy ice or snow loads.
Tree Resistance to Storm Damage
There are also characteristics that make trees less likely to sustain damage from ice or snow. These include 1) coarse branch structure which is less likely to accumulate ice, 2) conical branching, such as pine or spruce, 3) sound wood and strong branch attachments, 4) small tree stature, and 5) trees with deep rooting, which are stronger and less likely to fall over when under heavy load.
The following listing of tree resistance to damage was developed by Richard Hauer and Les Werner, associate professors of urban forestry at the University of Wisconsin-Stevens Point, and by Jeff Dawson, professor of forest biology at the University of Illinois at Urbana-Champaign. It was created from 42 primary publications of tree resistance to ice and snow damage.
Susceptible – American basswood, American elm, black ash, black cherry, black locust, black oak, Bradford pear, butternut, cottonwood, hackberry, honeylocust, jack pine, pin cherry, quaking aspen, red elm, river birch, Siberian elm, silver maple and willow.
Intermediate – American beech, boxelder maple, chestnut oak, choke cherry, Douglas fir, eastern white pine, green ash, Japanese larch, northern red oak, paper birch, pin oak, red maple, red pine, scarlet oak, Scotch pine, sugar maple, sycamore, tulip poplar and white ash.
Resistant – Amur maple, baldcypress, balsam fir, bitternut hickory, black walnut, bur oak, catalpa, Colorado blue spruce, crabapple, eastern hemlock, eastern red cedar, European larch, ginkgo, hophornbeam, horsechestnut, Kentucky coffeetree, littleleaf linden, mountain ash, northern white cedar (eastern arborvitae), Norway maple, Norway spruce, Ohio buckeye, pignut hickory, shagbark hickory, swamp white oak, sweetgum, white oak, white spruce, witch-hazel and yellow buckeye.
Get Recommendations from Nurserymen
The ornamental pear cultivar ‘Bradford’ is one example of a beautiful tree that unfortunately is genetically programmed to develop very tight upright branching, making trees susceptible to storm damage, usually when they reach 20+ years old. In response, the nursery industry has bred new cultivars of ornamental pear with better natural branch structure and less susceptible to damage.
This explains why it’s important to get good plant recommendations from knowledgeable nurserymen when you purchase a new tree. The cultivar ‘Chanticleer’, also known as ‘Select’ or ‘Cleveland Select’, is a better choice, less prone to storm damage. ‘Aristocrat’ is another good alternative, although more susceptible to fireblight than ‘Chanticleer’.
It's a good idea to think about choosing trees with resistance to storm damage when shopping for trees this spring. A little planning now could save you from headaches in the future.
Sources: Hauer, Richard, Les Werner, and Jeff Dawson. "Trees and Ice Storms: Developing Storm-Resistant Urban Tree Populations." Arborist News. February 2014, pages 32-35.
By Nicole Stoner, Nebraska Extension Horticulture Educator
Pesticides are a commonly used method of managing pests in our landscapes. However, pesticides are poisons, so they need to be handled carefully. It is at this time of the year that many educators from Nebraska Extension help to educate the public in proper uses of pesticides through pesticide education for farmers and commercial applicators. With spring coming right around the corner, it is a good time to reinforce those safety precautions to everyone who might be using pesticides.
"Pesticide" is the general term for any insecticide, herbicide, rodenticide, etc. Insecticides are specific to insects, herbicides are specific to weeds, and rodenticides are specific to rodents like mice. They are used to kill organisms that cause diseases and threaten public health. Mainly, in our landscapes, we use them to manage insects, diseases, and weeds that cause problems in our desired plants.
The Label Is The Law
Because pesticides can be dangerous if handled, stored, or disposed of improperly, always read and follow the label because the label is the law. This includes reading the label to ensure you are using the correct Personal Protective Equipment or PPE as it is often referred to. Most homeowner available chemicals will require gloves, long pants, long-sleeved shirt, and eye protection at most. Some chemicals will require things like a face shield or respirator.
Avoid Spray Drift
When using pesticides pay close attention to the weather. Do not apply pesticides on windy days, as the spray droplets are easily picked up in the wind and blown to non-target plants. Certain chemicals, such as 2,4-D, can volatilize or turn into a gas to move to non-target plants to cause damage or death. This can happen when the pesticide is applied when the temperature is 80 degrees Fahrenheit or higher on that day or up to 72 hours later.
Apply Products At Recommended Rates
Always apply pesticides at the label recommended rates. Pesticides that are applied at incorrect rates can cause resistance to occur in the pest, which would make the pesticide useless to that pest population. Also, make sure that you are applying the pesticide at the correct time for best control of the pest. It is also a good idea to switch between chemicals rather than use the same pesticide each time, which can also lead to resistance. So, if it is an insect pest in your vegetable garden, switch between sevin, eight, and bifenthrin on a rotating basis throughout the growing season, as the insect exists. Be sure to follow the label when applying any pesticide to edible crops, there will be a PHI or Pre Harvest Interval number. This PHI will dictate how many days to wait from when the pesticide is applied to when the crops can be harvested for consumption to ensure they are safe to eat. And finally, it is very important to know what pest you are dealing with before you apply pesticides to ensure you are using the correct chemical for the pest.
Prevent Pesticide Runoff
Pesticides tend to runoff into our water supply. Often, granular pesticides fall onto sidewalks and driveways to be blown or washed into the storm drains. Also, pesticides that are applied shortly before rain events are often washed into the storm drains causing pollution to our water supply. Because of the sensitivity of our environment to pesticides, it is always best to use an Integrated Pest Management, or IPM, approach. IPM is when you use multiple tactics to control pests rather than just utilizing pesticides. Methods of IPM include mechanical, or hand pulling weeds, cultural, or sanitation by removing infected leaves to reduce diseases, and biological, or protecting beneficial insects, as well as chemical methods to control pest populations.
By Nancy Urbanec, Nebraska Extension Nutrition Assistant
Natural events as well as man-made ones can lead to sudden power outages. Whether the outage is short-lived or prolonged, these outages can be dangerous. When your refrigerator/freezer or deep freeze goes out, special measures must be taken.
Being able to determine if food is safe and how to keep it safe will help you minimize the loss of food and reduce the risk of foodborne illness.
Keeping perishable foods such as meat, poultry, fish, eggs and dairy products should always be held at or below 40°F. Frozen foods should be held at 0°F or below. However, this can be difficult to achieve when the power is out.
Keeping the refrigerator and freezer doors closed as much as possible will help maintain the cold temperature. Most refrigerators will keep food safely cold for about 4 hours if it is unopened. A full freezer will hold the temperature for approximately 48 hours (24 hours if it is half full) if the door remains closed.
Digital, dial or appliance thermometers can help you know if the food is at safe temperatures. Keep an appliance thermometer in your refrigerator and freezer. This kind of thermometer can always indicate the temperature of the appliance no matter how long the power is out. Discard refrigerated perishable foods such as meat, poultry, fish, soft cheeses, milk, eggs, leftovers, and deli items after 4 hours without power. Checking other refrigerated items separately with a food thermometer can be helpful if you are not sure if the item is safe. Keep in mind that refrigerated food items must be below 40°F to be considered safe.
Purchase dry or block ice to keep your refrigerator as cold as possible if the power goes out for an extended period of time. Fifty pounds of dry ice should hold an 18-cubic foot full freezer at the proper temperature for 2 days. Be sure to follow safety precautions when working with dry ice.
Never put food outside in the snow or ice; it could attract wild animals, it may be difficult to maintain a proper temperature and could also thaw when the sun comes out.
Check frozen food for ice crystals. Food in a freezer that partially or completely thaws may be safely refrozen if the freezer temperature is at 40°F or lower.
Never taste a food to decide it is safe to eat. You cannot rely on appearance or odor to determine whether a food is safe.
If you have a power outage, whether due to Mother Nature or man-made, having items on hand that are shelf stable and can be eaten cold to reduce the number of times you open your refrigerator/freezer will help keep the air temperature colder.
Consider small can sizes that provide just the number of servings you will consume at one time. If power is off, refrigerating leftovers is not an option. Store single serving canned fruits and vegetables; dry milk, box shelf stable milk or pudding; canned fish, meat or beans, peanut butter and nuts; whole grain crackers, granola or ready to eat cereal. Also, plan to have on hand one gallon of water per day, per person for drinking, cooking and personal hygiene.
For more information check out “A Consumer's Guide to Food Safety: Severe Storms and Hurricanes”.