The ready-to-eat (RTE) chilled meals category is currently valued at over $8 billion in Europe and around $3 billion in the Asia Pacific region, and has experienced rapid growth in the period from 2009 to the beginning of 2013, growing at an annualised rate of 21 per cent and 11.5 per cent respectively.
Market data and projections for the category represent significant opportunities for Australian food manufacturers.
Conventional thermal preservation methods are generally used for the food safety management of extended shelf-life chilled meals.
There are no high pressure processed RTE meals in Australia, although there are currently a small number available in Europe processed by high pressure, but not by high pressure thermal treatment.
The significant safety margins incorporated into conventional thermal preservation methods can result in detrimental effects on product quality such as over-cooked flavour, colour and texture.
Additionally, extended shelf-life foods often require additional safety precautions such as low moisture or high acidity of less than pH 4.6 to inhibit bacterial growth, which places limits on recipe options used for multi-component meals.
Multi-component foods are complex. Each component is vulnerable to different bacteria and different components vary in their sensitivity to processing, for example, meat protein differs to vegetable protein which differs to carbohydrates.
Often one component is treated overly harshly in order to treat another sufficiently. Furthermore, there can be detrimental effects owing to the time it takes to heat the whole product through from the outside to the centre.
High pressure thermal processing
CSIRO, along with other food researchers internationally, has been studying high pressure thermal processing as a potential alternative to conventional thermal processing to deliver quality benefits to a range of processed foods, such as soups, sauces, as well as chilled and shelf-stable multi-component meals with extended shelf-life.
High pressure processing (HPP) uses very high hydrostatic pressures of up to 700MPa to inactivate vegetative microorganisms and achieve shelf-life longer than traditional thermal processes. HPP can also have other benefits such as enhanced crispness, colour, texture, flavour and nutrient retention, and control of some enzymatic reactions, depending on the product, conditions and application.
For high-acid foods, such as fruit juices, high pressures are sufficient for food safety. However, refrigeration is still required for these products as bacterial spores are highly pressure resistant at ambient temperatures.
To obtain microbiologically safe and stable low-acid foods such as multi-component meals where not all ingredients are acidic, added heat is necessary. By using pressure in combination with heat, it is possible to inactivate the spores at lower temperatures or shorter times than if the process was only thermal.
Developing the concept
CSIRO’s $40m food processing centre in Werribee, Victoria, is a world leader in HPP technology and therefore ideal for developing RTE meals using thermally assisted HPP with commercial potential.
With this application, we are targeting quality characteristics, such as fresh-like attributes, colour, texture and extended shelf life, making the products superior to those of other RTE meals on the market. Vegetables, for example, retain better colour and do not taste over-cooked as they can in traditionally thermally processed RTE meals.
After developing formulations inspired by CSIRO Total Wellbeing Diet recipes, we developed test products and conducted an initial risk assessment for process safety and shelf-life boundaries using natural hurdle technology to target food-borne pathogens and spoilage microorganisms, including endospores of non-proteolytic C.botulinum and Bacillus spp.
The process involves conventionally heating the product to initial temperatures of over 60°C, then packing the product and bringing it to about 90°C under pressures of about 600MPa.
Even though these temperatures are not substantially lower than those used in conventional pasteurisation, the total process time is significantly shorter than in conventional methods, as products under pressure don’t need to be heated for as long and the heating and cooling is rapid and uniform throughout the product, unlike in conventional treatment.
The combination of lower processing temperatures, shorter processing times and the uniform heating effect under pressure all contribute to the superior quality attributes of the RTE meals.
The work was made possible by CSIRO’s supporting capabilities in microbiology, particularly in thermal HPP inactivation kinetics and mechanisms, process engineering, food quality analysis and process validation.
Marketing the concept
CSIRO brought in food industry marketing specialist Ken Melia of FoMo to apply his understanding of the chilled meals category and develop potential point-of-sale packaging for the product. According to Melia, one key step in developing a breakthrough innovation is to base your product on consumer insights and market research.
“Companies can have the best technologies and the best people, but that doesn’t mean anything if they don’t have an emotional connection to the consumer,” Melia said.
“And if they don’t understand the consumer, the product’s not going to be on the shelf in a supermarket or in a restaurant and all they’re going to do is go out of business fast.”
The prototype meals’ were based on the following insights:
- Purchasing motivations: the number one reason for consumers purchasing RTE products is convenience, 74 per cent of consumers buy RTE meals because they don’t have time to cook and 13 per cent buy them because it’s cheaper than buying the ingredients; the quality is as good as cooking from scratch; or they taste better. As a result of this insight, the meals were produced in single serve formats for singles and couples and only take minutes to prepare in the microwave.
- Consumption occasions: 82 per cent of consumers eat RTE meals at dinnertime and 74 per cent consumers eat them for lunch, breakfast and snacks. This insight led to the prototype products being called Dinner is Served and Lunch is Ready.
- RTE product types: All-in-one meals, salads and desserts are the most popular types of RTE products and for its first products CSIRO chose to develop complete, all-in-one meals.
Lunch is Ready, Dinner is
Served
Lunch is Ready, a prawn casserole with tomato and basil, and Dinner is Served, beef and basmati rice with tomato and basil, are the results of CSIRO’s work so far. They have registered trade names and simple shelf-ready packaging designs.
They are low in fat and kilojoules and have a low GI. They require no artificial flavours or colours and the vegetables appear fresher than those in conventionally thermally treated meals.
The meals have a shelf life that is a minimum of 30 days under refrigeration. The products are pitched at the premium, time-poor markets in Asia and Australia for consumers with sufficient disposable income.
Points of difference
High pressure thermally treated meals have several major benefits over those prepared using current technology and methods. Similar chilled meals currently on the market have a shelf life of around 10 days depending on the product and process.
They are cooked, then packed, often in high-care environments, to reduce any post-cook bacterial contamination.
Meals that are microwave or thermally treated are processed in-pack and achieve around 30 days shelf life, but owing to the time-temperature treatment required for microbiological safety, the quality can be poor.
In comparison, thermally assisted HPP meals can have a significantly improved look, taste, texture and nutritional value.
An additional point of difference of these next-generation meals is a greater flexibility with recipe design.
We can now add more moderately acidic components and have a final product with an acidity higher than pH 4.6, making meals like stir-fries a possibility.
Food manufacturers, equipment and
packaging suppliers and retailers are welcome to call to discuss
co-development and commercialisation opportunities for the meals.
For
more information, visit www.innovativefoods2012.com.
The video of Ken Melia’s presentation can be viewed online at www.csiro.au/HPP-meals.
Food safety and HPP
In terms of safety, the main pathogens for chilled meal manufacturers to be concerned about are non-proteolytic and proteolytic Clostridium botulinum bacteria, which form stress-resistant spores.
Additionally, vegetative (non-spore forming) pathogenic bacteria, such as Salmonella Enteritidis and Escherichia coli (E. coli) can affect the safety of a food or beverage product.
High pressure processing (HPP) can inactivate vegetative organisms, such as Salmonella and E.coli, but C. botulinum spores are resistant to pressure, therefore HPP foods require refrigeration and need additional hurdles such as a pH less than 4.6 or a salt content higher than 3.5 per cent.
Thermally assisted HPP is capable of inactivating both
vegetative organisms and C. botulinum spores, allowing ready meals to
be produced with a reduced thermal load.
of ready meals.
The
‘next gen’ ready-to-eat chilled meals have arrived, thanks to a
patented high pressure thermal processing application that improves
quality aspects like fresh taste, texture, colour and nutrient value.
About the author
Lloyd Simons is business development manager at CSIRO. He can be contacted on 03 9731 3311 or Lloyd.Simons@csiro.au
