Jerky is one of the oldest ways of preserving meat, and one of the easiest to get wrong at home. Anyone who has left strips in a dehydrator overnight has probably assumed that a long, dry cook does the safety work. According to the United States Department of Agriculture’s Food Safety and Inspection Service (USDA FSIS), that assumption is a trap. This guide summarises USDA’s advice on making jerky at home. The figures are US federal guidance, given in Fahrenheit as USDA gives them.
A very old food
USDA describes jerky as a nutrient-dense meat made lightweight by drying: a pound of meat or poultry weighs about four ounces after it has become jerky. Because most of the moisture is removed, it is shelf stable and can be stored without refrigeration, which is why it suits backpackers. USDA says the word “jerky” comes from the Spanish “charque”, and that “biltong” is dried meat or game used in many African countries. It also notes that North American Indians mixed ground dried meat with dried fruit or suet to make pemmican.
Why a dehydrator alone is not enough
USDA says that when raw meat or poultry is dehydrated at home, in a warm oven or a food dehydrator, pathogenic bacteria are likely to survive the dry heat of a warm oven and especially the 130 to 140°F of a dehydrator. It says illnesses due to Salmonella and E. coli O157:H7 from homemade jerky have raised questions about traditional drying methods for beef and venison jerky.
The USDA Meat and Poultry Hotline’s recommendation is therefore to heat the meat to 160°F, and poultry to 165°F, before the dehydrating step. USDA says this step ensures any bacteria present are destroyed by wet heat. It points out that most dehydrator instructions do not include this step, and that a dehydrator may not reach temperatures high enough to heat meat to 160°F or poultry to 165°F.
USDA explains the reason. Within a dehydrator or low-temperature oven, evaporating moisture absorbs most of the heat, so the meat itself does not begin to rise in temperature until most of the moisture has gone. By then, USDA says, the bacteria have become much more heat resistant, so any pathogens present are more likely to survive and can cause illness. USDA also describes experiments with lab-inoculated venison, in which pathogenic E. coli survived drying times of up to 10 hours and temperatures of up to 145°F.
USDA’s step-by-step recommendations
USDA’s recommendations for homemade jerky include:
- wash hands thoroughly with soap and water before and after handling meat, and use clean equipment and utensils;
- keep meat and poultry refrigerated at 40°F or slightly below, and use or freeze ground beef and poultry within two days and whole red meats within three to five days;
- defrost frozen meat in the refrigerator, not on the counter;
- marinate meat in the refrigerator, and do not save marinade to re-use;
- steam or roast meat to 160°F and poultry to 165°F, measured with a food thermometer, before dehydrating;
- dry the meat in a food dehydrator that has an adjustable temperature dial and will maintain at least 130 to 140°F throughout the drying process.
USDA explains that after the initial heat treatment, the constant 130 to 140°F is important because the process must be fast enough to dry the food before it spoils, and must remove enough water to prevent microorganisms from growing.
Marinades and curing mixes
USDA says marinating does not make raw meat safe. It cites the University of Georgia and Colorado State University study, published in the Journal of Food Protection in 2004, which concluded that marination alone did not significantly reduce the pathogen compared with unmarinated beef slices. In those studies some samples showed complete bacterial destruction and others some survival, especially jerky made with ground beef. Another University of Georgia study cited by USDA, on ground beef jerky, found that jerky made with a curing mix containing salt and sodium nitrite had greater destruction of E. coli O157:H7 than jerky without it, and that jerky made with the curing mix and heated before dehydrating had the highest destruction rate. The authors concluded that concerns about E. coli O157:H7 in home-made ground beef jerky are minimised if the meat is precooked to 160°F before drying.
Wild game and sun drying
USDA advises special care with venison and other wild game, quoting researchers who note that venison can be heavily contaminated with faecal bacteria depending on factors such as the hunter’s skill and the location of the wound, and that deer carcasses are typically held at ambient temperatures, which can allow bacteria to multiply. USDA also says sun drying is not recommended for making meat jerky, because of the lack of a steady heat source and the potential for contamination from animals, insects, dust and bacteria.
How long does it keep?
USDA says commercially packaged jerky can be kept for 12 months, while home-dried jerky can be stored for one to two months.
What USDA does not cover
USDA’s jerky page discusses warm ovens and food dehydrators; it does not discuss drying jerky in a smoker. For general smoker safety, USDA’s separate smoking page is a better starting point, and it says a food thermometer is needed to monitor both the food and the smoker’s air temperature.
The bottom line
For safe homemade jerky, follow USDA’s order of operations: refrigerate and marinate properly, heat meat to 160°F (poultry to 165°F) first, then dry at a steady 130 to 140°F or higher, and use the jerky within one to two months. Do not rely on marinade, a long dry cook or a dehydrator’s temperature setting to make raw meat safe.
Keep reading
- Cooking at the Campsite: USDA Food Safety Guidance for Coolers, Fires and Stoves
- Thawing Meat for the Grill or Smoker: What USDA Says About Safe Methods
- Smoking Meat Safely: A USDA and UK FSA Checklist
- Safe Internal Cooking Temperatures for Grilling and Smoking (USDA Guide)