**2. Meat and meat products**

### **2.1. Raw fermented sausages**

The importance of starter and protective cultures for the manufacturing of safe and highquality fermented sausages has been known for a long time and, lactobacilli play an important role in their production [11,5]. *Lb. sakei* and *Lb. curvatus* are quite often the predominant LAB in dry-fermented sausage while other lactobacilli, such as *Lb. versmoldensis*, *Lb. plantarum*, *Lb. brevis*, *Lb. farciminis*, *Lb. alimentarius*, *Weissella* species, pediococci, and leuconostocs, usually occur in significantly lower numbers [12]. This has recently been also shown for different traditional salamis from North Italy [13-15]. However, other recipes and ripening conditions may promote other LAB as well. LAB isolated from dry spontaneously fermented sausages from 15 different producers in Spain included mainly *Lb. sakei* (66%), *Lb. curvatus* (26%), and *Lb. plantarum* (8%) [16]. For dry fermented Spanish 'chorizo' sausage *Lb. sakei* (69%), *Lb. curvatus* (16%) and *Pediococcus* (9%) have been reported [17]. From naturally fermented Greek dry salami about 50% of the isolates belonged to *Lb. sakei/curvatus*, 30% to the *Weissella* genus, 10% to *Lb. plantarum* and 3% each to *Lb. farciminis* and *Enterococcus (Ec.) faecium* [18]. In "Alheira", a fermented sausage produced in Portugal, *Lb. plantarum* and *Ec*. *faecalis* prevailed while other LAB, such as *Lb. paraplantarum*, *Lb. brevis*, *Lb. rhamnosus*, *Lb. sakei*, *Lb. zeae*, *Lb. paracasei*, *Leuconostoc (Leuc.) mesenteroides*, *Pediococcus (Pc.) pentosaceus*, *Pc. acidilactici*, *Weissella (Ws.) cibaria*, *Ws. viridescens* and *Ec. faecium*, occurred in lower numbers [19].

The main role of LAB is to convert fermentable sugars in the sausage batter to lactic acid, thereby contributing to product safety by creating unfavourable conditions for pathogens and spoilage organisms. The production of lactic acid has also a direct impact on sensory product quality by providing a mild acidic taste, and by supporting the drying process which requires a sufficient decline in pH. Furthermore, LAB influence the sensory characteristics of the fermented sausages by the production of small amounts of acetic acid, ethanol, acetoin, pyruvic acid, carbon dioxide, and their ability to initiate the production of aromatic substances from proteinaceous precursors [20-22]. The selection criteria for lactic acid bacteria to be used in the production of fermented sausage include (i) fast production of lactic acid (ii) good growth at different temperatures, (iii) homofermentative metabolism, (iv) persistence over the whole fermentation and ripening process, (v) nitrate reduction, (vi) ability to express catalase, (vii) no fermentation of lactose, (viii) formation of flavour, (ix) no formation of peroxide, (x) no formation of biogenic amines, (xi) no formation of ropy slime, (xii) tolerance or even synergy to other microbial components of the starter, (xiii) antagonism against pathogens, (xiv) antagonism against technologically undesirable microorganisms, (xv) improvement of the nutritional value of the sausage and, (xvi) economic factors [23]. Many homofermentative LAB associated with cured meat products are quite resistant to nitrite up to 200 ppm [24]. A new starter culture for raw sausages, 'BITEC Advance LD-20' from Frutarom Savory Solutions, containing *Lb. sakei* and *S. carnosus* is marketed as consistently providing a 'pleasant mild taste' while rapidly deminishing the pH value of the sausage batter. Rapid acidification is important for product safety while a high competitiveness against the spontaneous lactic flora is important for product quality. The culture can be used for firm and fresh raw sausages as well as sausage spreads.

The use of homofermentative lactic acid bacteria is desirable because acetic acid has an unpleasant taste as compared with lactic acid [25].

It must be kept in mind, however, that, although lactic acid production and pH reduction by LAB provide quite unfavorable conditions for pathogenic bacteria thereby preventing them from growing and contributing to their reduction, several pathogenic microorganisms are able to survive in fermented sausages under certain conditions for extended periods, especially during refrigerated storage of sparsely dried sausages. Pathogenic strains of *Escherichia (E.) coli*, *Listeria (Li.) monocytogenes* and *Yersinia (Y.) enterocolitica* are inactivated better after the initial fermentation and ripening stage if stored at ambient rather than at refrigeration temperature. Inclusion of a maturation period above refrigeration temperatures before distribution may increase the safety of these products [26-29].

### **2.2. Dry-cured hams**

130 Lactic Acid Bacteria – R & D for Food, Health and Livestock Purposes

mouthfeel or warmed-over flavour, resp. [9,10].

*viridescens* and *Ec. faecium*, occurred in lower numbers [19].

**2. Meat and meat products** 

**2.1. Raw fermented sausages** 

hams, and pasteurised, sliced prepackaged meats (cold cuts) [3-8]. The use of protective cultures in prepackaged, refrigerated sliced Bologna-type sausage and cooked ham against pathogenic listeria is a much discussed, sustainable technology for improving the microbial safety and quality of these products. It helps to avoid chemical preservatives, such as sodium lactate/potassium acetate additives, or repasteurisation in package after slicing and packaging, which both have a negative impact on sensory product quality leaving a numb

The importance of starter and protective cultures for the manufacturing of safe and highquality fermented sausages has been known for a long time and, lactobacilli play an important role in their production [11,5]. *Lb. sakei* and *Lb. curvatus* are quite often the predominant LAB in dry-fermented sausage while other lactobacilli, such as *Lb. versmoldensis*, *Lb. plantarum*, *Lb. brevis*, *Lb. farciminis*, *Lb. alimentarius*, *Weissella* species, pediococci, and leuconostocs, usually occur in significantly lower numbers [12]. This has recently been also shown for different traditional salamis from North Italy [13-15]. However, other recipes and ripening conditions may promote other LAB as well. LAB isolated from dry spontaneously fermented sausages from 15 different producers in Spain included mainly *Lb. sakei* (66%), *Lb. curvatus* (26%), and *Lb. plantarum* (8%) [16]. For dry fermented Spanish 'chorizo' sausage *Lb. sakei* (69%), *Lb. curvatus* (16%) and *Pediococcus* (9%) have been reported [17]. From naturally fermented Greek dry salami about 50% of the isolates belonged to *Lb. sakei/curvatus*, 30% to the *Weissella* genus, 10% to *Lb. plantarum* and 3% each to *Lb. farciminis* and *Enterococcus (Ec.) faecium* [18]. In "Alheira", a fermented sausage produced in Portugal, *Lb. plantarum* and *Ec*. *faecalis* prevailed while other LAB, such as *Lb. paraplantarum*, *Lb. brevis*, *Lb. rhamnosus*, *Lb. sakei*, *Lb. zeae*, *Lb. paracasei*, *Leuconostoc (Leuc.) mesenteroides*, *Pediococcus (Pc.) pentosaceus*, *Pc. acidilactici*, *Weissella (Ws.) cibaria*, *Ws.* 

The main role of LAB is to convert fermentable sugars in the sausage batter to lactic acid, thereby contributing to product safety by creating unfavourable conditions for pathogens and spoilage organisms. The production of lactic acid has also a direct impact on sensory product quality by providing a mild acidic taste, and by supporting the drying process which requires a sufficient decline in pH. Furthermore, LAB influence the sensory characteristics of the fermented sausages by the production of small amounts of acetic acid, ethanol, acetoin, pyruvic acid, carbon dioxide, and their ability to initiate the production of aromatic substances from proteinaceous precursors [20-22]. The selection criteria for lactic acid bacteria to be used in the production of fermented sausage include (i) fast production of lactic acid (ii) good growth at different temperatures, (iii) homofermentative metabolism, (iv) persistence over the whole fermentation and ripening process, (v) nitrate reduction, (vi) ability to express catalase, (vii) no fermentation of lactose, (viii) formation of flavour, (ix) no formation of peroxide, (x) no formation of Currently there are only a few publications which clearly substantiate the advantages of starter and protective cultures during raw cured ham production. On the other hand, starter cultures have been more and more implemented by meat industry into the production of dry-cured hams since the early 1980s [6,30]. These cultures are expected to be active under the harsh manufacturing conditions (low temperatures, high salt, lack of oxygen, presence of nitrite). LAB contribute to a moderate pH decrease which promotes the microbial stability as well as product texture, reduce stickiness and pH variations of the raw material. As an example, FSC-111 BactofermR from Chr.-Hansen A/S contains, besides a staphylococcal strain, also a strain of *Lb. sakei*.

The LAB induced acidification is usually more pronounced with injected or compound meats than with dry-salted ones. Modern turkey hams are produced by squeezing turkey breast over the screw of an extruder in the presence of (g/kg) nitrite curing salt (35), diphosphate (2,5), dextrose (2), water (100), starter culture and a spice compound, and subsequent tumbling until protein release. This mixture is then stuffed into fiber casings and left for 5 days at 2°C. This is followed by a fermentation step of around 16 hours at 22°C and 92-94% relative humidity until a pH below 5.4 is reached. Finally, the product is heated in a cabinet at 47 °C to a core temperature of 40°C. The desired result is a fresh looking product

with a slightly hyaline appearance with an optimum safety against undesired and pathogenic microorganisms [30].

The Role of Lactic Acid Bacteria in Safety and Flavour Development of Meat and Meat Products 133

**Figure 1.** Distribution of samples of refrigerated sliced cooked meats from the German retail market

**Figure 2.** Abundancy of different LAB species in refrigerated sliced cooked meats from German retail (n=50). sak, *Lb. sakei*; carn, *Leuc. carnosum*; curv, *Lb. curvatus*; viri, *Ws. viridescens*; mes, *Leuc. mesenteroides*; malt, *Cb. maltaromaticum*; Lb, *Lactobacillus* sp.; La, *Lactococcus* sp.; div, *Cb. divergens*; gel, *Leuc. gelidum*; Lc,

Biopreservation of meats refers to the control of pathogenic and spoilage microorganisms by a competitive microflora of desired indigenous microorganisms or so-called starter and protective cultures. The development of starter cultures for meats is tightly coupled with the industrialisation of the traditional artisanal processes. The production of safe and tasty fermented sausages by traditional technologies requires expert knowledge and continous attention to guide the fermentation into the desired direction, i.e. to promote the development of the desired microorganisms and to suppress the development of undesired microorganisms. Mistakes are heavily paid for by dangerous and/or low quality outcomes.

with respect to different LAB counts one week past the indicated shelf life [43].

*Leuconostoc* sp. [43].

**3. Biopreservation** 
