Antifungal activity of strains of lactic acid bacteria isolated from a semolina ecosystem against Penicillium roqueforti, Aspergillus niger and Endomyces fibuliger contaminating bakery products.
Thirty samples of Italian durum wheat semolina and whole durum wheat semolina, generally used for the production of Southern Italy's traditional breads, were subjected to microbiological analysis in order to explore their lactic acid bacteria (LAB) diversity and to find strains with antifungal activity. A total of 125 presumptive LAB isolates (Gram-positive and catalase-negative) were characterized by repetitive extragenic palindromic-PCR (REP-PCR) and sequence analysis of the 16S rRNA gene, leading to the identification of the following species: Weissella confusa, Weissella cibaria, Leuconostoc citreum, Leuconostoc mesenteroides, Lactococcus lactis, Lactobacillus rossiae and Lactobacillus plantarum. The REP-PCR results delineated 17 different patterns whose cluster analysis clearly differentiated W. cibaria from W. confusa isolates. Seventeen strains, each characterized by a different REP-PCR pattern, were screened for their antifungal properties. They were grown in a flour-based medium, comparable to a real food system, and the resulting fermentation products (FPs) were tested against fungal species generally contaminating bakery products, Aspergillus niger, Penicillium roqueforti and Endomyces fibuliger. The results of the study indicated a strong inhibitory activity - comparable to that obtained with the common preservative calcium propionate (0.3% w/v) - of ten LAB strains against the most widespread contaminant of bakery products, P. roqueforti. The screening also highlighted the unexplored antifungal activity of L. citreum, L. rossiae and W. cibaria (1 strain), which inhibited all fungal strains to the same or a higher extent compared with calcium propionate. The fermentation products of these three strains were characterized by low pH values, and a high content of lactic and acetic acids.
Valerio
Francesca
F
Institute of Sciences of Food Production, National Research Council, 70126 Bari, Italy.
Favilla
Mara
M
De Bellis
Palmira
P
Sisto
Angelo
A
de Candia
Silvia
S
Lavermicocca
Paola
P
D019342:Acetic Acid / Q000378:metabolism / Q000494:pharmacology; D000898:Antibiosis; D001234:Aspergillus niger / Q000187:drug effects / Q000254:growth & development; D001939:Bread / Q000382:microbiology*; D017753:Ecosystem; D055159:Endomyces / Q000187:drug effects / Q000254:growth & development; D005506:Food Contamination / Q000517:prevention & control*; D005658:Fungi / Q000145:classification / Q000187:drug effects / Q000254:growth & development*; D007558:Italy; D019344:Lactic Acid / Q000378:metabolism / Q000494:pharmacology; D007777:Lactobacillaceae / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification / Q000378:metabolism; D007778:Lactobacillus / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification / Q000378:metabolism; D048191:Lactiplantibacillus plantarum / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification / Q000378:metabolism; D007934:Leuconostoc / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification / Q000378:metabolism; D008826:Microbial Sensitivity Tests; D008969:Molecular Sequence Data; D010407:Penicillium / Q000187:drug effects / Q000254:growth & development; D016133:Polymerase Chain Reaction / Q000379:methods; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D013289:Streptococcaceae / Q000235:genetics / Q000254:growth & development / Q000302:isolation & purification / Q000378:metabolism; D014908:Triticum / Q000187:drug effects / Q000382:microbiology*
D012336:RNA, Ribosomal, 16S; D019344:Lactic Acid; D019342:Acetic Acid