Pathogen of least resistance

Food safety features daily in newspaper headlines, but this complex topic is often over-sensationalised. So when considering the benefits of new technologies, food manufacturers are constantly faced with the question: how would our consumers react to it? If the answer is 'badly', then it's back to the drawing board.

One contentious technology, used to kill listeria, was explored at a recent Leatherhead Food International (LFI) food safety forum. It was suggested that viruses called bacteriophages could be added to food as a method of keeping listeria under control. One unnamed food ingredients company said that it had considered developing this technology, but it came to the conclusion that, ultimately, it would be rejected by the consumer.

Despite this, Dr Boerboom, senior applications manager of EBI Foods, attempted to convince delegates that the technology was both safe and successful. He said that bacteriophages are a natural enemy of Listeria monocytogenes, claiming that as well as being harmless to humans their application does not alter the organoleptic properties of food.

EBI Foods' Listex P100 is a bacteriophage product, which has been recognised by Generally Recognised as Safe, the US Food & Drug Administration and US Department of Agriculture. It is used as a processing aid only against listeria, during the production of meat, cheese, fish, vegetables, fruit and other food products.

EBI Foods claims that its solution infects 99% of Listeria monocytogenes and can be considered as natural, organic and free from genetically modified organisms. Customers in the US have been using the product since 2005.

At the end of the presentation, one conference delegate asked Boerboom: "Are you not worried that if the tabloid press get hold of this the headlines might read: 'Mad scientist injects virus into foods'?"

"For this technology to be used within the EU it would need to go through a very strict novel food assessment to establish that it is safe to use," said Jamie Weall, principal advisor at Bodycote LawLabs - a consultancy and laboratory service.

"Personally, I think relying on such an ingredient is not the way forward," he added. "Food manufacturers should, instead, concentrate on having good procedures in place to prevent listeria - and this is why such a technology could be seen as being controversial."

The 'natural' minefield

The challenges of food safety are numerous, often leaving a long trail of labelling and marketing dilemmas behind them. And while consumers shun certain processes and technologies in favour of others, without entirely understanding them, "one thing is for sure", said Dr Josephine Head, chair of the food safety forum, "the drive is towards 'natural'."

The claim 'natural', however, brings us into a legal minefield, Head continued. "But not only that, what does it mean anyway?

"Pathogenesis is becoming more of an issue in food processing and unfortunately industry is having to comply with unscientific microbiological criteria, courtesy of the EU."

One answer to the 'natural' dilemma, claimed Dr Joss Delves-Broughton, senior applications specialist at Danisco Innovations UK, is the use of so-called 'protective cultures' in food processing as a means of food preservation. He suggested the use of bacterial cultures, particularly lactic acid bacteria, as a label-friendly way of preserving fermented foods such as meats, dairy products and vegetables.

Research has found that the protective cultures should inhibit undesirable organisms without any negative impact on the organoleptic qualities of the treated food product. Delves-Broughton added: "They are also becoming increasingly accepted by consumers, regulatory agencies and by the food industry."

Plants as preservatives

One area of food safety that is massively overlooked is the use of plant extracts to prevent food spoilage, according to the Royal Botanic Gardens (RBG), Kew. It claims that plants offer unique anti-bacterial properties that are accepted by consumers to be 'natural' and label-friendly.

According to professor Monique Simmons, head of sustainable uses of plants at the RBG, manufacturers face several challenges when it comes to using plant extracts in food. Legislation, for example, in some cases can prevent usage, and special permission or consent may have to be sought. Incorrect use of plants can also lead to high toxicity levels in foods - which has, in the past, led to police and hospital enquiries.

"Despite this, with the correct knowledge, there is so much unexplored potential to use plants for their antibacterial properties, especially at a time when consumers are demanding 'natural' products," Simmons added.

In the UK, raspberry leaves, goldenrod, bluebell, cowslip and figwort have traditionally been used for their preservative qualities. And, according to Simmons, by looking into the past to see how specimens have been used in food preservation, this could provide answers for the future.

Currently 35,000 species are being tested for their anti-bacterial properties. These include herbs, spices, pulses, beans and mint. Tea and eucalyptus, for example, contain epigallocatechin gallate, which has anti-bacterial properties.

"The complex nature of using plant species in food manufacturing creates a lot of hurdles. But it is possible to breed plants to contain higher amounts of certain compounds. The commercial potential is massively understated," Simmons added.

Concerns over food safety remain at the forefront of public attention, claims LFI's head of food safety Dr Evangelia Komitopoulou.

"It is critical that all food products are manufactured to the highest possible standards of safety and stability," says Komitopoulou. "And, apart from the obvious legal responsibility, there is a moral obligation to ensure that products are safe and fit for consumption."

LFI has been working on a number of research projects - trying to understand and identify spoilage organisms and bacterial pathogens in food, such as salmonella and Escherichia coli, for example.

Food spoilage organisms

Traditional identification of food spoilage organisms can be expensive and time-consuming, according to LFI. In the future, however, it intends to apply miniaturised microarrays routinely for the identification of food spoilage organisms in a high through-put and rapid manner. It is working towards a fully automated system that can work with 96 samples per run and can produce results within three to four hours.

At its nutritional chemistry laboratory, LFI is also is the process of completing a procedure that will detect melamine. Currently two matrices have been validated: chocolate and powdered baby food.

"When considering new technologies to ensure food safety, we need solid methods in place to evaluate them," Head concluded. "We can't start spraying things around and using cultures without fully understanding the implications.

"The wide use of some food safety technologies will inevitably spark contention in the UK. As well as solid quality assurance, we need to carefully consider how to communicate scientific complexities to the consumer." FM