Fermentation and acidification ingredients

Abstract

The distinct sensory qualities and remarkable shelf-life characteristics of fermented sausages, as compared to cooked sausages, are largely due to acidification of the meat batter. Traditionally, acidification of the raw meat is the result of a microbial fermentation process, i.e. lactic acid production by lactic acid bacteria (LAB). Acidification is generally combined with protection from oxygen (stuffing into casings), extensive salting, and curing (Chap. 1), and with an ageing stage for product maturation. The latter stage can be absent, short, or long, depending on the type of product, and leads to drying, resulting in a lower water activity, as well as to a complex and desired flavor formation (Campbell-Platt & Cook, 1995; Lücke, 1998). Sometimes, smoking or heating is applied as a last step in the manufacturing process. Heating is common in the United States, where regulations require a core temperature of 58.3°C before selling the end-product (Lücke, 1998). The almost anaerobic environment and the low pH and water activity values that prevail in the sausage are to be considered as the main hurdles that inhibit undesirable microbial growth and lead to a relatively stable end-product. In the case of spontaneously fermented sausage or sausage prepared through back-slopping, LAB that cause acidification of the meat and, hence, start the fermentation process, originate from the raw material or production environment. However, LAB can also be added deliberately by the sausage manufacturer as a starter culture to the meat batter (Campbell-Platt & Cook, 1995; Hugas & Monfort, 1997). In contrast to spontaneous fermentation, where the manufacturer relies on the presence of a "house microbiota" (counts of 10 2 -10 3 LAB per gram of fresh batter), the addition of a starter culture leads to high initial LAB counts (10 6 -10 7 per gram of fresh batter). This enhances acidification, leads to a more standardized and predictable production process, shortens the development of firmness and the overall ripening time, and improves food safety (Lücke, 1998). As an alternative to the use of LAB starter cultures, some manufacturers prefer to apply chemical acidulants, mainly to shorten the production process. Best results have been obtained with glucono-delta-lactone (GdL) (Barbut, 2006). However, a disadvantage of chemical acidulants is that they generally induce rapid and poorly controlled acidification, leading to inhibition of flavor development. The present chapter focuses on fermentation and acidification ingredients that are applied in sausage technology. In particular, it will discuss starter cultures for sausage fermentation, including both classical and novel, functional starter cultures, as well as chemical acidulants. © 2009 Springer Science + Business Media, LLC.