A powerful winter storm system last week brought snow, wind and tornadoes to the central U.S. and the Gulf Coast, threatening damage and power outages in its path.

The U.S. Department of Agriculture’s Food Safety and Inspection Service is offering tips on how to keep frozen and refrigerated foods at safe temperatures and how to determine if food is unsafe to eat.

Power outages and flooding that often result from weather emergencies compromise the safety of stored food, and planning ahead can minimize the risk of foodborne illness.

“Keeping food at safe storage temperatures is crucial to avoiding foodborne illness, and this can be difficult without electricity,” USDA Under Secretary for Food Safety Dr. Elisabeth Hagen said. “As the first winter storm of the season hits the U.S., make sure your family has appliance thermometers, coolers, and plenty of ice to keep perishable food below 40 degrees Fahrenheit until power is restored to your refrigerator and freezer. As a last resort for food safety, when in doubt, throw it out.”

The publication “Keeping Food Safe During an Emergency” can be downloaded and printed for reference during a power outage. FSIS’ YouTube video “Food Safety During Power Outages” also has instructions for keeping frozen and refrigerated food safe.

To get tweets about food recalls and weather-related food safety issues affecting just your state, follow @XX_FSISAlert, replacing XX with your state or territory’s postal abbreviation.

Steps to follow to prepare for a possible weather emergency:
• Keep an appliance thermometer in the refrigerator and freezer to help determine if food is safe during power outages. The refrigerator temperature should be 40 degrees or lower and the freezer should be zero degres or lower.
• Store food on shelves that will be safely out of the way of contaminated water in case of flooding.
• Group food together in the freezer — this helps the food stay cold longer.
• Freeze refrigerated items such as leftovers, milk and fresh meat and poultry that you may not need immediately — this helps keep them at a safe temperature longer.
• Have coolers on hand to keep refrigerator food cold if the power will be out for more than four hours.
• Purchase or make ice and store in the freezer for use in the refrigerator or in a cooler. Freeze gel packs ahead of time for use in coolers.
• Plan ahead and know where dry ice and block ice can be purchased.

Steps to follow if the power goes out:
• Keep refrigerator and freezer doors closed as much as possible.
• A refrigerator will keep food cold for about four hours if you keep the door closed.
• A full freezer will keep its temperature for about 48 hours (24 hours if half-full).
• If the power is out for an extended period of time, buy dry or block ice to keep the refrigerator as cold as possible. Fifty pounds of dry ice should keep a fully-stocked 18-cubic-feet freezer cold for two days.
• Take advantage of cold outdoor temperatures to make ice to bring inside, but do not leave food out in the snow to keep it cold. Outside temperatures can vary, and food can be exposed to unsanitary conditions and animals. Fill buckets, empty milk containers, or cans with water and leave them outside to freeze. Use this ice to help keep food cold in the freezer, refrigerator, or coolers.

Steps to follow after a weather emergency:
• Check the temperature in the refrigerator and freezer. If the thermometer reads 40 degrees or below, the food is safe.
• If no thermometer was used in the freezer, check each package. If food still contains ice crystals or is at 40 degrees or below when checked with a food thermometer, it may be safely refrozen.
• Discard any perishable food (such as meat, poultry, fish, soft cheeses, milk, eggs, leftovers and deli items) that have been kept in a refrigerator or freezer above 40° F for two hours or more.
• Discard any food that is not in a waterproof container if there is any chance that it has come into contact with flood water. Containers that are not waterproof include those with screw-caps, snap lids, pull tops, and crimped caps. Discard wooden cutting boards, plastic utensils, baby bottle nipples and pacifiers.
• Thoroughly wash all metal pans, ceramic dishes and utensils that came in contact with flood water with hot soapy water and sanitize by boiling them in clean water or by immersing them for 15 minutes in a solution of 1 tablespoon of unscented, liquid chlorine bleach per gallon of drinking water.
• Undamaged, commercially prepared foods in all-metal cans and retort pouches (for example, flexible, shelf-stable juice or seafood pouches) can be saved. Follow the Steps to Salvage All-Metal Cans and Retort Pouches in the publication “Keeping Food Safe During an Emergency.”  
• Use bottled water that has not been exposed to flood waters. If bottled water is not available, tap water can be boiled for safety.
• Never taste food to determine its safety!
• When in Doubt, throw it out!

Consumers with food safety questions can “Ask Karen,” the FSIS virtual representative available 24 hours a day at www.AskKaren.gov  or m.AskKaren.gov on your smartphone. Mobile Ask Karen can also be downloaded from the Apple and Android app stores.

Consumers can email, chat with a live representative, or call the USDA Meat and Poultry Hotline directly from the app. To use these features from Mobile Ask Karen, simply choose “Contact Us” from the menu. The live chat option and the toll-free USDA Meat and Poultry Hotline, 1-888-MPHotline (1-888-674-6854), are available in English and Spanish on weekdays from 10 a.m. to 4 p.m. ET.