Description of the bacteriocins produced by two strains of Enterococcus faecium isolated from Italian goat milk.
In this study two strains of Enterococcus faecium, M241 and M249, isolated from goat milk, were studied for their capability to produce antibacterial compounds. It was determined that the bacteriocins produced by both strains were active towards Listeria monocytogenes and Clostridium butyricum, and they did not have any activity with respect to other species of lactic acid bacteria. Enterocins A and B were targeted by polymerase chain reaction (PCR) and sequenced, after cloning, in both strains. The bacteriocins contained in the cell free supernatants were stable when subjected to treatments at high and low temperatures or with lipase, catalase and alpha-amylase. Whereas, the activity was lost when proteinases were used. Lastly, a co-culture experiment with L. monocytogenes in skimmed milk was performed. In the presence of the E. faecium strains, the pathogen showed a delay in the growth of about 6h and it reached a maximum counts of about 10(6) colony forming unit, two orders of magnitude low with respect to the control. This result suggests the possibility to use the strains studied as starter cultures to enhance food safety of dairy products.
Cocolin
Luca
L
Dipartimento di Valorizzazione e Protezione delle Risorse Agroforestali, Università degli Studi di Torino, via Leonardo da Vinci 44, 10095, Grugliasco, Torino, Italy. lucasimone.cocolin@unito.it
Foschino
Roberto
R
Comi
Giuseppe
G
Grazia Fortina
Maria
M
D000818:Animals; D000900:Anti-Bacterial Agents / Q000096:biosynthesis / Q000494:pharmacology; D001430:Bacteriocins / Q000096:biosynthesis* / Q000494:pharmacology*; D046972:Clostridium butyricum / Q000187:drug effects* / Q000254:growth & development; D018920:Coculture Techniques; D015169:Colony Count, Microbial; D003257:Consumer Product Safety; D016984:Enterococcus faecium / Q000302:isolation & purification / Q000378:metabolism*; D005516:Food Microbiology; D006041:Goats; D006801:Humans; D007558:Italy; D008089:Listeria monocytogenes / Q000187:drug effects* / Q000254:growth & development; D008892:Milk / Q000382:microbiology*
D000900:Anti-Bacterial Agents; D001430:Bacteriocins; C107799:enterocin A; C107801:enterocin B