There is a major drive towards natural rather than chemical or synthetic additives, as they are perceived by consumers to be safer and better for them. Indeed, the commonly used preservative sodium benzoate has been under the spotlight since 2006, as a result of its interaction with ascorbic acid in certain beverages, resulting in the formation of harmful chemicals.
But Dr Evangelia Komitopoulou, an authority on natural antimicrobials at Leatherhead Food International, told FoodNavigator.com that a lot more work needs to be done on natural preservatives before industry is in a position to cut out the chemicals – and still deliver safe products.
“Everyone is talking about a replacement for chemical preservatives, but first of all no-one has even defined what is natural,” she said.
While some research is being done on plant extracts, herbs and spices as possible natural preservatives, but Komitopoulou – who reviews as many as 200 such studies a month – has reservations about the quality of the research and its usefulness to industry.
She says they tend to omit or contain insufficient information on the sensory affect of the proposed preservatives on the foodstuff, or the toxicological question.
“We need a systematic approach to researching anti-microbials,” she said, “and identify areas in which the industry is in need.”
While it is still worth having the information that is included in the incomplete studies, she believes a scientific committee should be put together to develop a standard operating procedure.
At the moment, the studies are all using different controls – and some are not even using natural microbial isolates, she claims.
“People are not really paying attention.”
Leatherhead’s Food Safety Forum Day will take place on September 30, and Komitopoulou said that she will be throwing open the idea of a more organised approach to industry and scientific participants at the event.
When it comes to cultures, Komitopoulou noted that a lot of work has been done towards their potential in this area by major players like Danisco – and it is generally agreed that cultures can be considered natural.
However their use to date tends to be limited to dairy products, and it has not been broadened out to other application areas.
More research has been conducted on bacteriophages, or phage-derived proteins – in recent times. However amongst the limitations are a limited host range and the emergence of phage-resistant mutants.
In addition, it has yet to be seen whether consumer perception and acceptance will restrict their adoption in the food industry.
Activity at Leatherhead
Leatherhead has been conducting its own research into natural preservatives in recent years.
One aspect of this is microbial communication systems. Komitopoulou explained that different micro-organisms interact, or “talk” to each other in foods, and this is how they cause spoilage.
She said the aim is to identify the mechanisms by which they communicate, and to see how this knowledge could be put to use in food preservation.
The Leatherhead team is also looking at how microalgae can be used in food preservation, particularly in producing compounds that can inhibit growth.
The aim is to find out whether specific microalgae have anti-microbial activity against the main food spoilers, and if so how this information can be used by the industry.