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.