Improving food safety ‘the natural way’ would
certainly appeal to the increasingly health vigilant
consumer. Scientists in the UK have been looking at a
variety of natural antimicrobials that could extend
food shelf-life and improve its safety by reducing the
presence of pathogens.
According to researchers at Thames Valley
university in London, food products - such as fruit
juice, beer, beef or salmon fillets – could be
protected through different combinations of chitosan
extracted from shellfish, bacteriocins produced by
bacteria and components from essential oils.
The EU-funded project,
co-ordinated by
Professor Sibel Roller
at Thames Valley, developed mathematical models for
growth of Listeria monocytogenes and
Pencillium chrysogenum in a model food, using
natural preservatives, pH, water activity and
temperature as variables.
The scientists report
that they set to emphasise the synergistic effects of
the antimicrobials, but also included other components
such as salt, hydrogen peroxide, sulphite, organic
acids and EDTA.
New bacteriocins from
two lactic acid bacteria were found to protect beer
and beverages, and a combination of chitosan,
carvacrol and hydrogen peroxide showed to be efficient
in surface cleaning of stainless steel, reducing
counts of Listeria, Salmonella, Staphylococcus
and Saccharomyces.
Finally, a novel
combination of chitosan and carnocin allowed a reduced
content of sulphite addition to chilled pork sausages,
improved shelf life and a reduced risk of Listeria
innocua. The researchers also found synergistic
effects between chitosan and benzoate in juices and
culture media, chitosan and sulphite in comminuted
pork and sausages, and bacteriocins for the prevention
of spoilage in alcoholic beverages.
