For good sausage production practices, a series of factors must be evaluated and kept under constant scrutiny.
The first is meat selection. Meats should be sound, the fat should be of high quality and fresh. The connective tissue should be minimal, and the color of the meats should be excellent.
Second is understanding protein solubility. The myofibrillar proteins must be extracted and solubilized through the use of salt concentration. Understanding the necessary factors associated with salt solubility of muscle proteins is an extremely important activity.
Third, processors must be able to make the correct particle size of raw meats.
Clean cut, correctly sized particles that have been cut with sharp equipment are more important than most people realize. It is easy to make a product with dull equipment, which will result in poor texture and poor eating quality.
Fat addition is important. The amount of fat, the size of the fat particles and when it is added to the meat mixture are very important.
Temperature of fat also affects the way it is cut and how well it is incorporated in the meat mixture. The warmer the fat becomes, the more the fat is subject to oxidative rancidity and smearing.
Additional production practices of importance are the stuffing procedures, which includes the size of the stuffing horn, the size of the casings used, the presence and absence of air voids, and how firmly the product is clipped or tied.
Thermal processing is the next step, with first a fermentation process involving temperatures for the proper fermentation of the meat mixture, followed by the finishing steps or with the normal cooking and smoking of the products.
Surface condition is important. What is the color of the sausage surface? What is the firmness, and what is the overall appearance of the surface of the product and the cut surfaces of the product?
Chilling, following the thermal processing of the meat and holding products in a cold room for several days, allows products to "mellow out."
This mellowing action allows for the acid to build up by the starter cultures or by the natural occurring bacteria to have time and opportunity to equalize throughout the entire sausage mass.
This usually causes the pH to be a little higher because of greater uniformity of distribution.
Water activity and pH
The combined effects of water activity and pH are important in modern sausage processing.
Semi-dry products today have a lower pH and are less dry than hard or dry salamis.
Semi-dry products tend to have a pH of 4.8 to 5.1, and their water activity is in the range of 0.91 to 0.85.
Water activity decreases as the amount of available water for micro-organisms decreases.
When looking at conditions for dry sausage products, they certainly have a little higher pH or a little less acidity, but they are dryer than semi-dry products.
Typical pH of dry sausage today is 5.0 to 5.3, and the water activity is 0.85 to 0.80.
Fat is responsible for many properties, including flavor, juiciness and mouth texture.
Fat also has a dramatic effect on oxidative rancidity, a very strong negative effect on most meat products.
It is important to avoid frozen fats and old fats that have been kept in the freezer, where they continue to deteriorate and continue to be oxidized.
Avoid the use of very oily fats, such as brisket fat from beef cattle and very hard fats, such as kidney knobs.
The fat should be clean, cold and have sharp particle definition after it has been cut.
In many cases, fat should be ground through a pre-breaker and then through a one-inch plate while very cold.
There should be a minimum amount of mixing time involving the fat, since it tends to warm and smear.
Non-meat ingredients are important in the development of all sausage products, including salt, sodium nitrite and flavorings.
Sugars need to be discussed and understood more thoroughly in the use of fermented sausages.
The preceding is a condensed, edited portion of a presentation given by Roger Mandigo of the University of Nebraska during a fermented sausage workshop sponsored by the American Association of Meat Processors.