Agriculture Reference
In-Depth Information
laboratory media, but at the present time their use against food spoilage yeasts and
fungi in foods is lacking and thus it is not possible to give a realistic assessment
of their potential at this moment.
6.8 Future trends
It is now realised that a 'magic bullet' that will provide wide spectrum antimicrobial
effects allowing its use as a natural food preservative will not be forthcoming.
Researchers, therefore, will continue to make use of 'hurdle technology' with the
use of natural preservatives in combination at low concentrations to provide
effective preservation. Synergy is more likely to occur if the target cellular sites
for both agents are similar but not the same. If the modes of action are exactly the
same an additive effect is more likely. However, such an approach is not without
its disadvantages. If too many additives are used it can clutter the label. In many
countries, and especially the EU, full toxicological evaluation and demonstration
of a need both by industry and consumers will be required. Toxicological
evaluation will be costly and nobody will be prepared to meet such costs unless a
return on investment is guaranteed. A more common international approach for
approval of natural preservatives would accelerate their development.
Unfortunately, there is still a negative perception by many that microbially
produced preservatives such as nisin, other bacteriocins and natamycin are
'antibiotics' and as 'antibiotics' they will cause problems in development of resistance
to medical 'antibiotics'. Although, for example, the safety of nisin in this respect has
been clearly demonstrated (Hossack
et al.
1983; Wessels
et al.
1998; Cleveland
et al.
2001), it can be diffi cult to convey the message to decision-makers. Legislation in
many countries can be a long and time-consuming bureaucratic process.
A more systematic research approach in hurdle technology has been called for
to recognise the needs of industry and standardise methods of testing (Halliday
2008). There is perhaps a need for the formation of a scientifi c committee to
identify and standardise testing procedures on interactions between antimicrobial
agents. At the moment reports can be diffi cult to compare because researchers use
different methods and strains. Furthermore, reports often contain insuffi cient
information on the sensory effect of the proposed additives in the food, or whether
they are toxicologically safe or approved. Although there is a requirement for
replacement of chemical preservatives with natural alternatives, there is no
uniform or clear defi nition of what 'natural' means. The continuing need for foods
that are minimally heat processed, taste fresh, but have a long shelf life, and
contain only natural preservatives means that interest in the identifi cation,
isolation and use of natural antimicrobials will continue.
6.9 Sources of further information and advice
DAVIDSON
,
P
.
M
. ,
SOFOS
,
J
. and
BRANEN
,
A
.
L
. ( 2005 ),
Antimicrobials in Food
, CRC Press ,
Boca Raton, FL .
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