Biomedical Engineering Reference
In-Depth Information
Chapter 3
Application of Lactic Acid Bacteria and Their
Bacteriocins for Food Biopreservation
3.1
Bacteriocins and Bactericin-Producing Strains
Microbes and/or their natural products have played key roles in the preservation of
foods during mankind history (Ross et al.
2002
). The rational exploitation of micro-
bial antagonism based on scientifi c knowledge has been possible after the discovery
of the biochemical nature of the antimicrobial substances produced by microorgan-
isms. Bacteriocins produced by the lactic acid bacteria (LAB) have several features
that still make them attractive for food preservation: (1) LAB have a long history of
safe use in foods; (2) LAB and their cell products—including bacteriocins—are
generally recognised as safe; (3) LAB bacteriocins are not active and non-toxic on
eukaryotic cells, and (4) due to their proteinaceous nature, bacteriocins are expected
to become inactivated by digestive proteases and not exert signifi cant effects on gut
microbiota at the concentrations ingested with the food. In addition, LAB bacterio-
cins may be suitable as preservatives, given (1) their sometimes broad antimicrobial
spectrum, including food poisoning and spoilage bacteria, (2) their synergistic
activity with other antimicrobials, (3) a bactericidal mode of action exerted at mem-
brane level, which avoids cross resistance with antibiotics of clinical use, (4) stabil-
ity under the heat and pH conditions achieved under processing of many foods, and
(5) their genetic determinants are usually plasmid-encoded, which facilitates genetic
manipulation and development of producer strains with improved technological
properties. Bacteriocin-encoding plasmids may be transferred to other strains by
natural processes, but at the same time there is a risk for loss of the plasmid together
with the bacteriocin production capacity.
Application of bacteriocins in food preservation may be benefi cial in several
aspects (Thomas et al.
2000
; Gálvez et al.
2007
): (1), to decrease the risks of food
poisoning; (2) to decrease cross contamination in the food chain; (3) improve the
