Making homemade jerky, with a food dehydrator, is a fairly straightforward process; trim the fat from lean meat, slice the meat into 1/8 to 1/4 inch thick strips, if desired, marinate and or season the meat strips and then remove the moisture from the meat by placing the meat strips in your food dehydrator for up to 12 hours. However, properly dehydrating the meat can be a somewhat tricky process. When making jerky it is important to strike the right balance between:
Heating the meat slowly enough to dry it without overcooking it. If you heat meat too fast, case hardening can develop. Case hardened food has the outermost portion of the food dried while the interior remains moist. This situation typically results when too high of a drying temperature is used. Case hardened foods will spoil due to microbial growth.
Heating the meat quickly enough to eliminate moisture from the meat so that harmful
bacteria will not have a chance to grow.
Heating the meat to a high enough temperature to kill bacteria that can cause illness.
The United States Department of Agriculture’s (USDA) suggestion for striking the right balance in properly dehydrating meat is as follows: “The USDA Meat and Poultry Hotline's current recommendation for making jerky safely is to heat meat to 160 degrees Fahrenheit (71 degrees Celsius) and poultry to 165 degrees Fahrenheit (74 degrees Celsius) before the dehydrating process. This step assures that any bacteria present will be destroyed by wet heat. After heating (to a temperature of 160 degrees+ Fahrenheit), maintaining a constant dehydrator temperature of 130 to 140 degrees Fahrenheit 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.”
The USDA’s dehydrating concern revolves around heating the meat to a high enough temperature to kill food pathogens and bacteria like e coli, listeria and salmonella that may be present. Some food dehydrators may not reach a consistent temperature of 160+ degrees Fahrenheit (71+ degrees Celsius), thus there could be potential for bacteria that is present to survive the dehydrating process. Per the USDA, “The danger in dehydrating meat and poultry without cooking it to a safe temperature first is that the appliance (dehydrator) will (may) not heat the meat to 160 degrees Fahrenheit (71 degrees Celsius) and poultry to 165 degrees Fahrenheit (74 degrees Celsius) – temperatures 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.”
To back up their recommendation, the USDA cites several scientific studies on dehydrating meat and making jerky. Per the USDA, “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. In the jerky studies, some samples showed total bacterial destruction and other samples showed some bacterial survival – especially the jerky made with ground beef (emphasis by food-dehydrator.com). 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 degrees Fahrenheit (63 degrees Celsius).’
The USDA also cites scientific studies that tested ground beef jerky made with and without a curing mix of salt. The USDA cites, “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 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 (the authors) concluded, “For ground beef jerky prepared at home, safety concerns related to E. coli are minimized if the meat is precooked to 160 degrees Fahrenheit prior to drying.’’
Published 6/2/2009 12:00:00 AM