Around the world, meat from domestic and wild animals is used to make jerky. Meats from domestic animals include beef, pork, goat and mutton or lamb. Wild animals including deer, kudu, springbok, kangaroo, and bison are also used. Recently, other animals such as turkey, ostrich, salmon, alligator, crocodile, tuna, emu, horse, camel and even earthworm have entered the market. Jerky is a popular meat item because it is ready to eat and does not require refrigeration.
Jerky is simply defined as meat cut in strips and dried. It is considered a convenience food because the shelf life is a period of months.
All that is needed to produce basic jerky is a low-temperature drying method, and salt to inhibit bacterial growth. However, modern jerky manufacture now includes a cooking or lethality step to eliminate pathogenic bacteria. Drying is the world's oldest and most common method of food preservation. Drying technology is both simple and readily available to most of the world's culture.
Meat Preparation Jerky is lean meat that has been trimmed of all visible fat and cut into thin strips and then dried to prevent spoilage.
Modern manufactured jerky is normally marinated in a seasoned spice rub or liquid as the method to add the salt and other seasonings to the strips. Some product manufacturers finely grind meat, mix in seasonings, and press the ground meat into flat shapes. The advantage in this method is the consistency in shape and thickness. Some additional form of chemical preservative, such as sodium nitrite, is often used in conjunction with the historical salted and seasoning procedure to prepare jerky.
Heating and Lethality The red meat (such as beef and pork) needs to be cooked to a minimum 72 °C and poultry to a minimum 74 °C (internal temperature)— temperatures at which pathogenic bacteria are destroyed. (Hint: Since the meat strips are thin, the best way to determine internal temperature is to place the thermometer probe between two pieces of meat). It is important to cook the meat prior to the dehydrating process, because, after drying, bacteria become much more heat resistant. Drying or Dehydrating Dry the product in an oven with a temperature of 60 -70°C.
Generally, the product is dried to approximately one third its original weight. This results in a product with a moisture to protein ration in the general range of 0.75 to 1. However, this amount of dryness does not necessarily ensure product safety. To achieve product safety and allow for storage at non-refrigerated temperatures the jerky needs to be dried until it reaches the water activity of 0.85. Water activity, by definition, is the measurement of water vapor pressure generated by the free or non-chemically bound water in foods and other products. (Bound water and moisture content cannot be measured with this method). Pure water has a water activity of 1.00. Most foods have a water activity of 0.95. Pathogenic bacteria cannot grow at a water activity of 0.85 or below. Water activity is measured by a device simply called a water activity meter. Cooling Chill the product to an internal temperature of 2° C or less. Packaging Either nitrogen gas flushed or vacuumed packed results in optimal packaging.
To prevent the oxidation of any remaining fat that was not removed during the trimming process the sealed packages often contain small pouches of an oxygen absorber. Additionally, vacuum sealed packages are not 100 percent oxygen free; thus, the need for the oxygen absorber. In conclusion, the critical manufacturing steps to keep in mind are:
Consistency of shape and thickness during preparation
Cook before drying to ensure lethality of bacteria
Accurate measurement of internal temperature
Dry to water activity of 0.85 or below to ensure product safety for this non-refrigerated finished product.