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Refrigerated Food Safety Forum - Interview with speaker Peter Wareing, Leatherhead Food Research

Peter Wareing, Principal Food Safety Advisor from Leatherhead Food Research explores what are the most dangerous foodborne diseases and what actions can producers take to remain vigilant across the cold chain.


Peter has over 30 years’ experience in food and agricultural development work, specialising in food mycology research, and has worked in countries across Africa, Asia and South America. At Leatherhead Food Research he develops and manages a portfolio of food safety, HACCP, auditing and microbiology training courses and provides consultancy and troubleshooting for clients.

Peter’s specialties include Food Safety, HACCP, Auditing, Risk Assessment, Food Microbiology, Food Mycology, with speciality expertise covering specifically soft drinks, sauces and dressings, bakery products and dried foods


Predicting and extending shelf life in chilled goods - Microbial surveillance and food borne disease


Please detail your role at Leatherhead Food Research and the kinds of projects that you are involved in.

At Leatherhead as a Principal Food Safety Advisor I get involved in all sorts of work, from delivering food safety related training courses, to consulting on client issues, answering enquiries and helping colleagues across Leatherhead with food safety on their projects.  Some typical projects that I have been involved with recently are:  being an expert witness in court on food poisoning cases involving restaurants, helping to identify the source of a spoilage problem in fruit purees and jams, validation of soft drink thermal and non thermal processes, troubleshooting contamination issues in dairies, an evidence based review of a company’s microbiological criteria, to name a few!

Your role as Principal Food Safety Advisor requires expert knowledge of the industry and developments - how do you remain up-to-date with what is going on in food safety?

I’m very fortunate as that’s what we do at Leatherhead. It’s our job to be up to date and keep our members informed, not just on safety but also on related issues such as regulations, processing, and any health issues that impinge upon food safety; salt reduction for example. So consulting with colleagues who are specialists and sharing ideas and the findings of our own research industry databases is invaluable. Of course we receive a lot of information from government and other sources, so I can tap into that and I subscribe to trade and other journals. I attend or speak at conferences, listen to clients’ issues and needs.

With consumer demands focusing more and more on green/natural products, how do you feel sustainability concerns are affecting innovation in the chilled food sector?

There are positive and negative impacts of sustainability on innovation; on the one hand the consumer demands for green, or natural, or ‘clean label’ means that companies have to innovate to keep or increase their market share.  On the other hand, this can mean that products, processes or ingredients become out of bounds if the emphasis is on sustainability.  This may mean more ethical sourcing of ingredients and the use of natural preservatives, for example.  Sometimes companies think that you have to choose between the largely social benefits when sustainable products are developed, compared with the cost of that approach.  But the environmentally friendly methods that come from sustainability can allow for reduced inputs, and increased revenue from the perception that these products are healthier. In fact some companies regard sustainability as the cutting edge of innovation.

Similarly, extending shelf life on chilled products, especially dairy and ready meals, is big news - what challenges does a manufacturer face when extending the shelf life of their product?

As you might expect, this is a complex subject; the answer will depend in part on the type of product under consideration.  For example, if the product has a relatively high water activity and pH, and the process will not kill psychrotropic Clostridium botulinum, then the 10 day rule usually still applies. The biggest challenge is probably the drive to reducing sugar, salt and other preservatives from products; the quest for a ‘clean label’, coupled with lighter processing regimes for ready meals but still retain the shelf life.  Equally, increasing the shelf life is difficult because the recipe and intrinsic control factors will have been optimised for the current shelf life.  Usually, there is much more flexibility with dairy products, since many are fermented, which increases their safety factor considerably.

The obvious challenges are to make sure that the products are still safe, and look and taste acceptable to the end of their shelf lives.

Your presentation will look in to foodborne diseases in relation to shelf life. In your opinion, what are the most dangerous foodborne diseases and what actions can producers take to remain vigilant across the cold chain?

That’s a tricky question, as the most common cause of bacterial food is Campylobacter, which cannot grow in food, as it cannot grow below 30°C, so strictly speaking it is unaffected by temperatures changes that relate to shelf life.  Listeria monocytogenes is proving to be an increasing problem for the elderly, and in fact it is the pathogen most adapted to life in the chill, under modified atmospheres.  E. coli has been shown to be a pathogen that can adapt, and some new strains have caused some major food poisoning outbreaks in chilled foods over the past few years.  And let’s not forget Salmonella, which still causes food poisoning; new strains are still being detected.

How do you feel that packaging suppliers and cold chain distributors can help to ensure safety in chilled products?

This is a really interesting question; the right packaging can ensure that products can reach the expected shelf life, rather than fall short of it.  Maintenance of the chill chain is very important, any break in the chain can allow chill-tolerant pathogens such as Listeria monocytogenes to start to grow, which may allow it to reach an unsafe level before the end of the shelf life.  The right packaging can allow gas exchange on the one hand, or prevent loss of the modified atmosphere conditions, on the other.  Smart packaging for products and monitoring aids linked to RFID on pallets, cartons or bulk loads can show the environmental profile of the product.

Some types of smart packaging can deliver a slow release antimicrobial into the product atmospheric space, slowing or preventing the growth of pathogens and spoilage agents.

Finally, what are you most looking forward to about the Refrigerated Food Safety Forum and what do you hope to gain from attending/speaking?

I’m really excited by the wide ranging topics, and the flow of the chilled food story through the two days.  Of particular interest are the perspectives from around the world, and the technology-based solutions to improving and monitoring chilled products shelf life. I’m also hoping to network with a wide range of people that will be attracted to the format and content of the event.