by Larry Hand
The beef snack market is a growing $152 million business. They are one of the few snacks from beef products that are shelf stable.
Although snack sticks are often an acidified product either through fermentation or encapsulated acid, like the dried sausages such as pepperoni and hard salami, the care and extensive drying times necessary for manufacturing those products are not characteristic of this family of meat items.
Because of the typical small diameter, they are dried very quickly through the normal drying process-where in a typical dried sausage product, smearing and too hasty of a drying process can lead to disastrous product failures.
The primary problem with beef jerky is mold growth after packaging. This comes from contamination during packaging or inadequate packaging material. In most facilities, processors try their best to package in a cool room. If the dry jerky product is left sitting too long in the packaging room, then the moisture in the cool room condenses on the warm, dry product. What was once shelf-stable jerky now has a higher moisture/protein ratio, and mold growth occurs. The answer to this potential problem is to control packaging (low humidity room) and place desiccant in the packages or jars to remove the moisture from the air in the stores.
Product manufacture
The basic steps in the manufacture of a typical snack stick involve grinding the raw materials, mixing the spices and other added ingredients, acidulation, stuffing into small diameter collagen casings, hanging, fermentation, cooking and drying. Stuffing and hanging is critical to the salable yield, as smoke stick marks are not acceptable as only straight snack sticks are salable.
This has resulted in the development of many different hanging methods and equipment to decrease the number of smoke stick marks. One of the simplest requiring the minimum investment in new equipment is to stuff an entire casing stick and then hang in large, long loops over a smoke stick on the top of the truck and around one rung on the bottom of the truck. The bottom stick is then placed under the bottom rung of the truck providing tension on the sausage, thus straightening out the product. One difficulty in producing snack sticks in large volume is the time required to stuff out the product in such a small diameter.
Acidification is the next major step in the process. This is either done by the addition of encapsulated acid (usually citric) or through the use of starter cultures of lactic acid producing bacteria. The chemical acidulants are usually encapsulated in vegetable oils that have different melting points.
These release the acid into the meat system as the appropriate temperature is achieved which prevents the denaturation of the protein prior to the stuffing and forming process.
Great care must be exercised in the use of these products as the encapsulation can be fragile. To obtain the best results, the encapsulated acid must receive the least mechanical action possible. This usually involves adding the encapsulated acid at the very end of the mixing, and if reground after mixing, stuffing immediately as the grinding and mixing process can break the encapsulation and the acid is released too soon. If encapsulated acid is subjected to extremes in temperature during shipping and storage, the encapsulation can be damaged. Freezing is not recommended for storage as encapsulation has the potential for fracturing.
There are many benefits to using encapsulated acids including control over how much acid one wants to add to the product, and the processing speed when compared to a typical fermentation or starter culture. Instead of fermenting for eight to 12 hours, one can move directly into the cooking and drying stage.
Lactic acid starter cultures is another method to decrease the pH in snack sticks to increase the shelf life. Microorganisms used in starter cultures inhibit the growth of many pathogenic bacteria. Rapid fermentation is recommended to insure product safety and time/temperature/pH guidelines incorporated into quality control programs.
Starter cultures are sold in two forms: freeze dried or frozen. In the United States., the most popular form is frozen. Care must be taken to thaw the culture appropriately in distilled water prior to use. USDA regulations allow the use of culture plus water to equal 0.5 percent of the batch weight without label declaration of water. During fermentation of the products, it is important to provide adequate humidity (70 to 90 percent), temperature (90 to 110 degrees F) and time (eight to 24 hours) for the starter culture.
After fermentation, most products are cooked to at least 137 degrees F for trichina control but most are cooked to 150 to 160 degrees F using dry cycles to dry the product and lower the moisture protein ratio. A study conducted by Oklahoma State University shows that snack sticks processed at a lower processing humidity had longer shelf life.
12-month shelf life
An average commercial shelf life on snack sticks is typically 12 months. However, when one adds cheese or other ingredients, that changes the mixture of microorganisms and shelf life. Since these products are commonly found at room temperature on convenience store or tavern counters, the humidity, temperature and light abuse presents the potential for food safety problems. Shelf stability, however, can be controlled by attention to control parameters of pH and moisture or water activity.
With the use of either encapsulated acid or starter cultures, pH control is important. In ball park terms, the lower the pH, the less spoilage organisms grow. Fresh meat has a pH in the range of 5.6 to 6.0. To achieve a significant means of bacterial control, a pH of 5.0 should be achieved.
Each batch of meat is slightly different and responds differently to either starter cultures or encapsulated acid. Therefore, a means of measuring pH is needed for successful production of acidified meat products. The measurement of pH is a relatively simple process. Take about one part of product (ground) and 10 parts of distilled water, stir or mix, insert pH meter and record the result.
The pH meter must be standardized on a daily basis with buffers of known pH (recommended 4.0 and 7.0) to provide accurate readings. The measurement of pH can vary from simple pH papers (not accurate in smaller ranges) to hand-held probes that can be inserted into the sausage to laboratory models. The cost of these range from $5 (papers) to $700 to $900 (portable meter and solutions or lab top meter and solutions). The important thing about measuring pH is to maintain some control over the process and product.
Dr. Hand is in the department of animal science (meat) at Oklahoma State University. This paper is a portion of a presentation he made during the 23rd annual Midwest Meat Processors Seminar at Kansas State University.