**6. Bioactive compounds as antifungal agents**

Several lactobacilli species are reported to have antifungal activity (Gerez et al., 2009; Muhialdin et al., 2011b; Plockova et al., 2001; Stiles et al., 1999). The antifungal compounds consist of organic acids, reuterin, hydrogen peroxide and other peptides (Table 1). The organic acids are active at low pH and the activity relies on the un-dissociated form of the acids. Recently, interest has dramatically increased in the use of bioactive peptides produced by LAB as an antifungal agent. The use of protein-like compounds are preferred over the use of acids because their activity is present over a wide range of pH and they are heat stable compounds which are ideal for use in heat processed foods (Muhialdin et al., 2011a). Cyclic dipeptides cyclo (Phe-Pro) and cyclo (Phe-OH-Pro) were produced by the *L. coryniformis* subsp. *coryniformis* Si3 strain and were inhibitory to *Aspergillus* sp. (Magnusson, 2003; Ström et al., 2002). Ryan et al. (2011) observed that sourdough made with *L. amylovorus* DSM 19280 had a longer shelf life compared with bread produced with calcium propionate. The selected strain inhibited the growth of *Fusarium culmorum* FST4.05, *Aspergillus niger* FST4.21, *Penicillium expansum* FST4.22, *Penicillium roqueforti* FST4.11 and *L. amylovorus* DSM 19280 and produced seventeen antifungal compounds.




**Table 1.** Antifungal compounds produced by lactic acid bacteria and their target fungi
