Continuous improvement drives both processing and technology in the meat and poultry category. The difference is that production improvements are implemented quickly, while technical advancements take years and even decades to take root.
Coextruded sausage casings follow this arc. Purists may insist on natural casings, but man-made casings are gaining share in production of bratwursts, kielbasas, hot dogs and other sausage categories. Cellulose or collagen -- the protein that provides the connective tissue in mammals -- typically is used to produce these casings.
Whether natural or man-made, casings by tradition were stuffed by hand. “This was and still is a very slow process that is susceptible to variations and also presents more challenges in terms of sanitation,” observes Shai Barbut, a meat scientist and faculty member at the University of Guelph in Ontario. That began to change in the 1990s with the advent of collagen gels or pastes extruded onto and encircling meat as it exits the stuffer, creating a film that is fixed onto the meat with a calcium solution.
Automation drives contemporary food production, and “all large companies are relying on high-speed linkers, coextrusion or both to produce thousands of identical sausage links every hour,” adds Barbut, who provides a primer on the process in The Science of Poultry and Meat Processing, an open-source textbook he created as a service to the industry.
Change comes in baby steps, however, and a prolonged adoption stage was required. Collagen film originally was commercialized for surgical use; sausage applications didn’t occur for another 30 years. Even today, coextruded collagen casings account for less than half the artificial casings on sausages sold in North America, though most of the largest manufacturers are migrating to continuous systems.
With three coextrusion lines, Denmark, Wis.-based Salm Partners LLC may be the technology’s biggest user. (A fourth line produces chicken sausage in Decatur, Ala., in a joint venture with Wayne Farms.) The contract manufacturer produces more than 110 million lbs. of private label and branded sausages a year, quadruple the throughput before incorporating coextrusion in its processes.
Coextrusion doesn’t account for all of Salm’s success, of course. Sous vide cooking adds a post-packaging pasteurization step that helps push refrigerated shelf life of RTE sausage beyond 300 days. But coextrusion moves stuffing from a batch to a continuous process, preventing starvation of downstream activity between batches and helping optimize throughput.
Salm uses coextrusion systems from Marel Townsend. Those machines can produce about 11,000 lbs. of rope or linked sausage per hour. That’s less than some continuous cook/smoke/chill lines, but the cross linking that occurs between the meat and the collagen film provides texture and flavor that allow products to compete in the higher-value segment of the market.
In a paper presented at the American Meat Science Assn.’s Reciprocal Meat Conference, Salm’s Paul Hargaten cites the added benefit of applying liquid smoke during the post-stuffing drying process. Liquid smoke solution helps “set color but more importantly cross-links the casing [with the previously applied collagen] and the casing to the meat batter,” thereby enhancing quality of finished goods.
Handtmann Maschinenfabrik (www.handtmann.de/en/handtmann-group/) fabricates a similar coextruder using alginate, and in 2012 added the ability to twist the sausage ends. Collagen casings represent about one-third the cost of natural casings, according to Scott Cummings, a regional manager at Robert Reiser & Co. Alginate is even lower cost. “Alginate solution is around 5 cents per lb.,” Cummings says, compared to 14 cents for collagen. Reiser’s CC215 coextruded alginate machine is capable of producing 1,000 1-oz. breakfast links per minute.
Shifts in consumer preference can shrink the timeline of change considerably. Demand for natural and organic chicken that is free of antibiotics illustrates this.
Feed supplements play a big role in keeping young chicks healthy with little or no antibiotics, but interventions at the embryonic stage also pay dividends. Ultraviolet and chemical fogging are among the treatments being applied before chicks hatch. To fortify its no-antibiotics-ever strategy, Perdue Farms uses baby wipes to clean the 13 million eggs it needs each week to maintain downstream processing.