**4. Concluding remarks**

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

*pentosaceus*), *Lc. lactis* and *Streptococcus thermophilus.* 

*Lb farciminis Lb fermentum Lb gallinarum Lb gasseri Lb heveticus Lb hilgardii Lb johnsonii Lb kefiranofaciens* 

*Lb kefiri Lb mucosae Lb panis* 

to bacitracin will vary greatly (Ammor et al, 2007; Coppola et al., 2005).

Lactobacillus plantarum

Lactobacillus heterofermentative

**Table 6.** *Lactobacillus* (Lb) species with QPS- status according to EFSA (from Korhonen, 2010).

Lactobacilli are generally susceptible to antibiotics inhibiting the synthesis of proteins, such as chloramphenicol, erythromycin, clindamycin and tetracycline, and more resistant to aminoglycosides (neomycin, kanamycin, streptomycin and gentamicin. While some species show a high level of resistance to glycopeptides (vancomycin and teicoplanin), susceptibility

**Species**

Pediococcus pp

Enterococcus spp

**Table 7.** Microbiological break points (g mL-1) categorizing some LAB species as resistant (Adapted

*Lb acidophilus Lb amylolyticus Lb amylovorus Lb alimentarius Lb aviaries Lb brevis Lb bucheneri Lb casei Lb crispatus Lb curvatus Lb delbrueckii* 

**Antibiotic** 

Ampicillin Vancomycin Gentamycin Kanamycin Streptomycin Neomycin Erythromycin Clindamicin Tetracycline Chloranphenicol Trimethoprim

Key: IR, intrinsically resistant

from Ammor et al., 2007)

Lactobacillus obligate homofermentative

defined taxonomic group, such as a genus or group of related species could be made based on establishing identity, body of knowledge, possible pathogenicity and end use (European Commission 2007). The 33 *Lactobacillus* species shown in Table 6 are the ones that in 2007 EFSA stated could be considered to have QPS-status. In addition to *Lactobacillus* species, also other LAB species have been granted QPS –status. They include three leuconostocs, (*Ln. citreum, Ln. lactis* and *Ln. mesenteroides*), three pediococci (*P. acidilactici, P. dextrinicus* and *P.* 

> *Lb paracasei Lb paraplantarum Lb pentosus Lb plantarum Lb pontis Lb reuteri Lb rhamnosus Lb sakei Lb salivarius Lb sanfranciscensis*

*Lb zeae* 

Leuconostoc

Lactococcus lactis

Streptococcus thermophilus

LAB are important in cheese processing because (i) they increase food safety through the release of lactic acid and bacteriocins, (ii) produce aromas and flavor and accelerate the maturation process of cheese via their proteolytic and lipolytic activities, bringing economic advantages to the industry, (iii) bring about desirable food textures via release of polysaccharides that increase the viscosity and firmness, and reduce susceptibility to syneresis, (iv) they may be used to deliver polyunsaturated fatty acids (PUFA) and vitamins, leading to dairy products with increased nutritional value, (v) specific probiotic strains contribute to liberation of health-enhancing bioactive peptides improving absorption in the intestinal tract, stimulating the immune system, exerting antihypertensive, antithrombotic effects, or functioning as carriers for minerals.

Novel insights arising from use of Bioinformatics, Systems Biology and Bioengeneering approaches will offer perspectives for the application of a new generation of starter cultures for cheese-making, having enhanced functional features and offering several health, marketing, and technological advantages, contributing to the development of small and medium sized enterprises on the one hand, and product diversification of large companies on the other.

However, there are still many developments to be achieved towards fully realizing the many foreseen potential of LAB or their products. For example extraction and purification of bacteriocins is still difficult as they form micelles or clumps with the nitrogen sources already in the growth medium. On the other hand while genetic engineering may offer many solutions related to optimal use of LAB, they may not be easily allowed by food legislation.
