HIPSTER wants to change the face of food processing

When it comes to food, at least in a Western context, we want it all, we want it now and we want it chemical-free. Consumers do not want to be limited to eating only local and seasonal produce; however, they expect their food to make its journey in an unadulterated state, and with colours, flavours and textures intact.

Against this backdrop is the necessity for food to be safe from bacteria.

The fight against food poisoning

About 75% of the new diseases that have affected humans over the past 10 years have developed from animals or products of animal origin.

According to the Europe Food Safety Authority (EFSA), Campylobacteriosis remains the most commonly reported foodborne disease in the European Union, with over 190,000 human cases annually. Common routes of the bacterium are raw milk and undercooked poultry.

Salmonella, often transmitted by eggs, is the second most common intestinal infection, with over 100,000 human cases reported each year.

Listeriosis is also causing great concern, and continues to rise in Europe. In 2014, there were 2161 confirmed cases, resulting in 210 deaths, the highest annual number reported since 2009. Dairy products, vegetables, fruit and seafood are the possible vehicles of the infection.

“Globalisation and the movement of people have brought about trade in food, but there are also the chemical and biological hazards that come with it — and they know no borders,” explained Marta Hugas, head of the Biological Hazards and Contaminants Unit at EFSA.

For food processors, the challenge is huge. “Consumer preferences for convenient food that is easy to prepare, but as fresh as possible and minimally processed, are sidelining techniques like freezing, canning and chemical preservatives. Such techniques are very effective in terms of safety but may affect food quality and taste. Now we have to create new technologies to meet these demands and to ensure the long shelf life required by distant export markets,” said Geraldine Duffy, researcher at the Head Food Safety Department of the Teagasc Food Research Centre in Dublin, Ireland.

Duffy’s department is contributing to a European project called HIPSTER, which is attempting to validate and implement a food processing technology combining high pressure processing (HPP) with temperature (HPT).

A century-old technique…

Using high pressure to preserve and sterilise foods is a century-old technique known as high pressure processing (HPP) or Pascalisation, from the 17th-century French scientist Blaise Pascal, famous for studying the effects of pressure on fluids.

Applied to certain foods, high pressure can render inactive some microorganisms such as yeast, mould and bacteria, and some enzymes too, which contribute to deteriorating foods when processed.

In Japan since 1990, HPP has been used to preserve some juices, jellies, and jams; it is now used to preserve fish and meat, salad dressings, rice cakes and yoghurts. In the US, the technique has been used for guacamole: it did not change the taste, texture or colour, but the product’s shelf life increased from three to 30 days.

High pressure prolongs guacamole shelf life from three to 30 days. Image credit: Sweetonveg

However, HPP has its limitations. After HPP, most of the enzymes are intact, which means the colour and texture (and also flavour) are not stable during chilled shelf life. Another important difference is food safety of non-acidic products, like vegetables or meat. Due to bacterial spores, non-acid food is not safe after HPP treatment.

…with a modern twist

Enter the new version of HPP, the snappily-named ‘high hydrostatic pressure in combination with temperature' (HPT) technique, which adds a heating step to the high pressure processing.

The combination of a preheating stage and high pressure is expected to sterilise food products and ensure greater food safety, freshness and nutritional quality, while extending shelf life. In addition, HPT promises to be environmentally friendly thanks to its low energy costs and reduced water consumption.

“We are testing its efficacy on prepared meals with extended shelf life, including soups and ready-to-eat meals that contain chicken and fish. If the HPT technology works, it could be applied to other foodstuffs in the future,” explained Duffy.

The high hydrostatic pressure on its own inactivates vegetative bacteria on the food, but not the spores that could make it unsafe or lead to spoilage.

Thus, scientists are investigating if submitting the food product to the high pressure treatment, in combination with temperatures of about 90°C, will inactivate such spores while guaranteeing quality, safety and taste and in addition to giving a long shelf life — conditions that are much valued by the market and the catering industry.

HPT promises much, but has not yet been scaled up and fully implemented into the food industry to be compared against existing food processing techniques.

The HIPSTER project

The European HIPSTER research project is aimed at validating, implementing and marketing this new method.

Nine European partners (five industries and four RTD organisations) will work together until August 2017, to implement HPT in the food industry on an industrial scale.

HIPSTER addresses the main barriers preventing the first market introduction and full deployment of HPT. The project will focus on the following activities:

R&D:

• Identify process windows (pressure/temperature/time) ensuring inactivation of pathogens and spoilage microorganisms using defined model systems and real foods.

Prototyping:

• Engineering and construction of a full-scale HPT equipment unit suitable for processing at different pressure/temperature ranges. The equipment is based on an innovative design of the vessel. Include auxiliary units for the preheating and cooling.
• Construction of tools (sensors, gauges, etc) for process monitoring.
• Develop a public database containing microbial kinetic parameters determined under well-defined processing conditions for guidance to food industry and control authorities.

Validation:

• Pilot and industrial scale testing of HPT treatments.
• Experimental production of a range of new food products (ready-to-eat and ready-to-use fish, meat and vegetable products).
• Shelf life studies.
• Viability study: compliance with legal requirements, economic feasibility and sustainability.
• Demonstrating in full-scale operational conditions the sustainability and techno-economic feasibility of the equipment and tools developed in collaboration with end users from the food sector.

Dissemination and exploitation:

• Communication of the technology to the broad public.
• Market plan to be deployed by each of the industrial partners.

Meanwhile, elsewhere in Europe

In the fight to keep food safe, clean and marketable, Scientists working for the project i3Food are developing three different technologies: pulsed electric field preservation (PEF-P) of liquid food products, like fruit juices and smoothies; high pressure thermal sterilisation (HPTS) for ready-to-eat meals; and low shear extrusion of cold food products, mainly ice-cream.

Other European research is contributing by improving the monitoring process.

“We need sensors to control and monitor the whole process from the beginning in order to avoid an effect of overprocessing, which could cause quality losses in the food product afterwards,” explained Stefan Töpfl, food technologist at the German Institute of Food Technologies (DIL).

Töpfl said that these techniques will reduce damage to the product by avoiding excess treatment intensity and energy use at every stage of processing.

“I think in Europe we have a high level of food safety, but we now face the challenge of finding a variety of preservation techniques to maintain this level while at the same time increasing the quality of the product in terms of consumer demands,” said Töpfl.

Image credit: ©Pavel Losevsky/Dollar Photo Club