[at-l] Food Safety of Jerky

[WHHAWKINS@aol.com]

Those of you who make your own jerky may find this usefull. This is a link to 
the info online.  
<A HREF="http://www.fsis.usda.gov/OA/pubs/jerky.htm">Food Safety of Jerky</A> 
I copied the page and it is in this message.

Wildbill
_______________________________________________________
Food Safety and Inspection Service
United States Department of Agriculture
Washington, D.C. 20250-3700

Consumer Education and Information

October 1998
Online Version Slightly Revised 10/27/98

FOOD SAFETY OF JERKY

When raw meat or poultry is dehydrated at home – either in a warm oven 
or a food dehydrator – to make jerky which will be stored on the shelf, 
pathogenic bacteria are likely to survive the dry heat of a warm oven 
and especially the 130 to 140 °F of a food dehydrator. Included here is 
the scientific background behind drying food to make it safe and the 
safest procedure to follow when making homemade jerky.

What is Jerky?
This product is a nutrient-dense meat that has been made lightweight by 
drying. A pound of meat or poultry weighs about four ounces after being 
made into jerky. Because most of the moisture is removed, it is shelf 
stable – can be stored without refrigeration – making it a handy food 
for backpackers and others who don’t have access to refrigerators.

Jerky is a food known at least since ancient Egypt. Humans made jerky 
from animal meat that was too big to eat all at once, such as bear, 
buffalo, or whales. North American Indians mixed ground dried meat with 
dried fruit or suet to make "pemmican." "Biltong" is dried meat or game 
used in many African countries. Our word "jerky" came from the Spanish 
word "charque."

How Can Drying Meat Make it Safe?
Drying is the world’s oldest and most common method of food preservation
. Canning technology is less than 200 years old and freezing became 
practical only during this century when electricity became more and more 
available to people. Drying technology is both simple and readily 
available to most of the world’s culture.

The scientific principal of preserving food by drying is that by 
removing moisture, enzymes cannot efficiently contact or react with the 
food. Whether these enzymes are bacterial, fungal, or naturally 
occurring autolytic enzymes from the raw food, preventing this enzymatic 
action preserves the food from biological action.

What are the Types of Food Drying?
There are several types of food drying. Two types of natural drying – 
sun drying and "adibatic" (shade) drying – occur in open air. Adibatic 
drying occurs without heat. Solar drying sometimes takes place in a 
special container that catches and captures the sun’s heat. These types 
of drying are used mainly for fruits such as apricots, tomatoes, and 
grapes (to make raisins).

Drying from an artificial heat source is done by placing food in either 
a warm oven or a food dehydrator. The main components of an electric 
food dehydrator include:
•a source of heat; 
•air flow to circulate the dry air;
 •trays to hold the food during the drying process; and 
•mesh or leather sheets to dry certain types of foods. 

Why is Temperature Important When Making Jerky?
Illnesses due to Salmonella and E. coli O157:H7 from homemade jerky 
raise questions about the safety of traditional drying methods for 
making beef and venison jerky. The USDA Meat and Poultry Hotline’s 
current recommendation for making jerky safely is to heat meat to 160 °F 
before the dehydrating process. This step assures that any bacteria 
present will be destroyed by wet heat. But most dehydrator instructions 
do not include this step, and a dehydrator may not reach temperatures 
high enough to heat meat to 160 °F.

After heating to 160 °F, maintaining a constant dehydrator temperature 
of 130 to 140 °F during the drying process is important because:
•the process must be fast enough to dry food before it spoils; and •it 
must remove enough water that microorganisms are unable to grow. 

Why is it a Food Safety Concern to Dry Meat Without First Heating it to 
160 °F?
The danger in dehydrating meat and poultry without cooking it to a safe 
temperature first is that the appliance will not heat the meat to 160 °F 
– a temperature at which bacteria are destroyed – before it dries. After 
drying, bacteria become much more heat resistant.

Within a dehydrator or low-temperature oven, evaporating moisture 
absorbs most of the heat. Thus, the meat itself does not begin to rise 
in temperature until most of the moisture has evaporated. Therefore, 
when the dried meat temperature finally begins to rise, the bacteria 
have become more heat resistant and are more likely to survive. If these 
surviving bacteria are pathogenic, they can cause foodborne illness to 
those consuming the jerky.

What Research Findings Exist on the Safety of Jerky?
There have been several scientific studies of meat dehydrating and lab 
tests on jerky samples by the following professionals: Judy Harrison, 
Cooperative Extension Service, University of Georgia;   Mark Harrison, 
the Center for Food Safety and Quality Enhancement, Department of Food 
Science and Technology, University of Georgia; Richard A. Holley, Food 
Research Institute, Agriculture Canada, in Ontario; and William Keene of 
the Oregon Health Division. In studies, the meat dehydrated included 
slices of beef from the round, loin, or flank; corned beef slices; and 
ground beef formed in jerky presses. Keene examined homemade venison 
jerky which infected 11 people with E. coli O157:H7. 

In a related work, factors affecting the heat resistance of E. coli 
O157:H7 was the subject of an April 1998 piece by J. Kauer et al., 
Letters of Applied Bacteriology, Vol. 26, No. 4, page 325.

In the jerky studies, some samples showed total bacterial destruction 
and other samples showed some bacterial survival – especially the jerky 
made with ground beef. Further experiments with lab-inoculated venison 
showed that pathogenic E. coli could survive drying times of up to 10 
hours and temperatures of up to 145 °F.

A recent study by the Harrisons and Ruth Ann Rose, also with the 
University of Georgia, was published in the January 1998 Journal of Food 
Protection, Vol. 61, No. 1. The authors analyzed ground beef jerky made 
with a commercial beef jerky spice mixture with and without a curing mix 
containing salt and sodium nitrite.

Half of the ground beef was inoculated with E. coli O157:H7 before 
making it into jerky strips and dehydrating it. The authors found that 
in both the heated and unheated samples, the jerky made with the curing 
mix had greater destruction of bacteria than jerky made without it. The 
jerky made with the mix and heated before dehydrating had the highest 
destruction rate of bacteria. 

They concluded, "For ground beef jerky prepared at home, safety concerns 
related to E. coli O157:H7 are minimized if the meat is precooked to 160 
°F prior to drying."

What are the USDA Meat and Poultry Hotline’s Recommendations for Making 
Homemade Jerky?
Research findings support what the Hotline has been recommending to 
callers. Additionally, safe handling and preparation methods must always 
be used, including:
•Always wash hands thoroughly with soap and water before and after 
working with meat products.
•Use clean equipment and utensils.
•Keep meat and poultry refrigerated at 40 °F or slightly below; use or 
freeze ground beef and poultry within 2 days; whole red meats, within 3 
to 5 days.
•Defrost frozen meat in the refrigerator, not on the kitchen counter.
•Marinate meat in the refrigerator. Don’t save marinade to re-use. 
Marinades are used to tenderize and flavor the jerky before dehydrating 
it.
•Steam or roast meat and poultry to 160 °F as measured with a meat 
thermometer before dehydrating it.
•Dry meats in a food dehydrator that has an adjustable temperature dial 
and will maintain a temperature of at least 130 to 140 °F throughout the 
drying process.

Are There Special Considerations for Wild Game Jerky?
Yes, there are other special considerations when making homemade jerky 
from venison or other wild game. According to Keene and his co-authors, 
"Venison can be heavily contaminated with fecal bacteria – the degree 
varying with the hunter’s skill, wound location, and other factors. 
While fresh beef is usually rapidly chilled, deer carcasses are 
typically held at ambient temperatures, potentially allowing bacteria 
multiplication."

Is Commercially Made Jerky Safe?
Yes, the process is monitored in federally inspected plants by 
inspectors of the U.S. Department of Agriculture’s Food Safety and 
Inspection Service. Products may be cured or uncured, dried, and may be 
smoked or unsmoked, air or oven dried. The following terms may be on 
processed jerky products:
•"Beef Jerky" – produced from a single piece of beef.
•"Beef Jerky Chunked and Formed" – produced from chunks of meat that are 
molded and formed, then cut into strips.
•"Beef Jerky Ground and Formed or Chopped and Formed" – produced from 
ground or chopped meat, molded and cut into strips. Beef Jerky 
containing binders or extenders must show true product name (e.g., "Beef 
and Soy Protein Concentrate Jerky, Ground and Formed").
•"Species (or Kind) Jerky Sausage" – the product has been chopped and 
may be dried at any stage of the process, and it is stuffed into 
casings.
What is the Safe Storage Time for Jerky?Commercially packaged jerky can 
be kept 12 months; home-dried jerky can be stored 1 to 2 months.

For additional food safety information about meat, poultry, or eggs, 
call the toll-free USDA Meat and Poultry Hotline at 1 (800) 535-4555; 
Washington, DC, call (202) 720-3333; TTY: 1 (800) 256-7072. It is 
staffed by home economists, dietitians, and food technologists weekdays 
from 10 a.m. to 4 p.m. Eastern time, year round. An extensive selection 
of food safety recordings can be heard 24 hours a day using a touch-tone 
phone.

The media may call Bessie Berry, Manager, USDA Meat and Poultry Hotline, 
at (202) 720-5604.

Information is also available from the FSIS Web site: 
http://www.fsis.usda.gov

Consumer information pieces can be received by fax by calling the FSIS 
Fast Fax at 1 (800) 238-8281; Washington, DC area, call (202) 690-3754.

"The USDA is an equal opportunity provider and employer."



For Further Information Contact:
FSIS Food Safety Education and Communications Staff
Meat and Poultry Hotline:
•1-800-535-4555 (Tollfree Nationwide) •(202) 720-3333 (Washington, DC 
area) •1-800-256-7072 (TDD/TTY) 

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