Two market analyst reports paint a glowing future for the chilled food sector and modified atmosphere packaging. Protein packs are constantly being refined and produce is enjoying an extended honeymoon. Rodney Abbott reports

In its report Key Note says that, between 1997 and 2001, the UK market for chilled prepared foods increased by 9.4% to reach a value of £6.58bn. It believes growth will come from convenience foods, cooking sauces, soup and pasta. Key Note expect the market to be worth £7.57bn in 2006.

Conversely, MSI says that the volume of modified atmosphere packaging reached 2.5M tonnes in 2001, representing an increase of 13%. It is estimated that the volume of products packed using a modified atmosphere increased by a substantial 48% between 1997 and 2001.

The retail MAP market can be divided into three main types of packs – preformed trays with lidding film, flow packs and thermoformed trays with lidding film.

The largest proportion of the total market for MAP in 2001 was accounted for by preformed tray systems, which accounted for 38% of the MAP retail food market.

A leaking container can lead to cross-contamination so it is not surprising to find that the recently introduced food hygiene standards have had a big effect on hermetic sealing, in particular PVC stretch overwrap where consistent hermetic sealing is difficult to achieve.

The regulations have seriously impacted on the poultry market, a market that has a short shelf life and which has relied on PVC stretchwrap because of its cost effectiveness. Packed in this way there is a high risk of poultry product contaminating the shelves.

Poultry products are now presented in a completely different way. The supermarkets became sensitive to the fact that they were the last owners of that product before it went to the consumer so they wanted the sector to be squeaky-clean Europe wide.

So it is not surprising to learn that one of the biggest drivers in this sector in the last few years has been the decision by retailers to confine their role to retailing and not food packaging… and so the demand for case-ready has grown as a consequence.

At one time primals of beef were sliced back store, placed on a tray and processed through a stretch overwrap. Now fresh meat arrives case-ready after being centrally prepared by the supplier.

Elsewhere in mainland Europe case-ready is expanding for economic factors, rather than reasons related to hygiene. In the UK, the sale of meat in modified atmosphere packs is profitable. In mainland Europe it is not. That is the fundamental difference.

Globally, the UK is seen as a benchmark for case-ready marketing. Little has changed in modified atmosphere packaging over the last five years. The biochemistry remains the same with the three prime gases – oxygen, carbon dioxide and nitrogen being used in different permutations according to product, season and source.

However, the discipline has become more refined. Loose percentages of mixes of gases have been refined to within 5%. The old gases, say for meats, was purely 75% oxygen and 25% CO2. The oxygen was there for the colour. The CO2 was put in to suppress the growth of bacteria.

However, nitrogen is a lot cheaper than CO2 and scientists found that they could bring the level of CO2 down with a careful balance of nitrogen.

Recent claims by industrial gas providers regarding the benefits of argon over nitrogen in modified atmosphere packaging are overstated, according to Professor John Irven, director of Air Technology at Air Products packaged gases division.

“There have been several theories as to why argon seems to have beneficial effects over nitrogen but none of them completely fit the pattern of what is observed,” he comments.

The respiration rates of various packs were measured after being packaged with nitrogen or argon in the gas mixture to compare the effects of the two atmospheres. Although the results showed a decrease in respiration rates with argon, this decrease was marginal.

Air Products, therefore, decided to undertake a set of comparative experiments in collaboration with The University of Lincolnshire and Humber-side, using both argon and nitrogen on two commonly available enzymes, one involved in the respiration process (malic dehydrogenase) and one involved in the oxidative browning of fruit (tyrosinase).

The results confirmed that there was only a slight reduction in activity using argon compared with nitrogen.

“It is clear from both a scientific and commercial perspective that the reality of argon versus nitrogen has, until now, not been represented in a balanced way.”

Cryovac is also sceptical of the claims made for argon, claiming that the use of this gas to extend shelf life is debatable and argues that the gas, like helium, is better used to sense leak protection – more process control than food protection.

Cryovac is involved in two distinct fresh MAP markets – protein and produce.

Produce is still very much alive and, if you exclude oxygen, it starts to respire from the CO2 that’s developed [anaerobic respiration].

That means that the product can look fine from the outside but, when it is cut open, it can show signs of break down.

So in closed packs there are microscopic holes in the film to allow a certain amount of oxygen through and allow products to continue to respire. In these packs oxygen levels must not fall below 4.5%.

We tend to talk about MAP as sealing the oxygen out but, in terms of produce, it means getting it in and making sure it continues to be there for the storage life of the product.

Over the last two or three years, the prepared produce sector has grown like Topsy. While Cryovac has begun to develop a significant presence in this market with the acquisition of Dolphin Packaging, the main driving force has come from other European companies such as Amcor, EPL and Rexam.

The company has been active over the last three years on protein-based foods where the market place has been changing most. One of the reasons for this is that MAP for protein is high technology packaging, whereas MAP for produce packaging tends to use less sophisticated materials.

“Technology is in the understand-ing, not necessarily in the materials,” says Cryovac market development manager Leo Docherty. Campden and Chorleywood Food Research Associa-tion has done a lot of research in determining these levels.

“The supermarkets that have driven this have chosen the packaging materials so the same vegetable or fruit often needs an atmosphere that complements the material and pro-vides the right respiration rate.

“Fruit is prepared in different ways. It needs a different atmosphere because its respiration rate is affected. It’s also dependent on where it is harvested and the time of year.

“This is a food technologist’s job, rather than a packaging technologist’s job. The producer will then do their own development work to determine what’s best for them. It really is kept at this level with produce.”

The Autobar Disposables Group makes punnets for soft fruit and containers for a range of salads, some of which are supplied by Veriplast International. The Autobar Group is busy developing products from a range of materials including PP, OPP, EPS, APET and, most significantly, poly lactic acid.

The group is making punnets from PLA. Complementary lids with air holes are also available from Autobar. I spoke to chief executive Charles Shaw.

“The biodegradable market will grow but it is very much a niche market in Europe at the moment,” he says. “As the price of the raw material comes in line with the price of plastics raw materials, it will become more and more competitive.

“The biodegradable market is being driven by customers like specialised packers, supermarkets and Coca-Cola, which are keen to be seen as environmentally aware, and retailers who are using it as a point of communication with their customers.

“The cost of making a starch-based replacement is 2.5 times more expensive than PS or PP. The process currently being pioneered by Cargill Dow has yet to become economically viable.

“The system basically involves the cultivation of PLA from maize into bead form from which we can extrude and thermoform products. So far two commercial plants are producing PLA in quantity and they are sited in the US but there are smaller pilot plants in Europe, one in Holland and another in Scandinavia.

“The chilled produce sector is growing extremely well for us at the moment. The vegetable market is growing at about 7-10% every year. The whole market is growing at about 15%.

“The growth of the vegetable sector, as in the soft fruits market, is being held back because new products are continuously being introduced to the market.”

Punnets first made an impact in the soft fruits industry in the Mediterranean countries and the major consumers came from Germany, Holland and the UK.

Originally, these fruits were transported to markets in timber boxes in semi-refrigerated lorries in a day and a half. On arrival 50% of the fruit was found to be rotten. The other 50% had to be sold in a day and a half before it, too, became unsale-able.

   With the advent of the plastics punnet, the life of soft fruits was considerably length-ened. Firstly, the punnet allowed air to circulate around the pack which was placed in timber boxes and transported in a chilled container lorry and the goods reached the retailer 100% intact.

This meant that that packaging could go straight onto the shelf without the need to be picked out and sorted and the supplier was saving on re-handling costs.

Current packs have been designed to let even more air circulate in transit. The punnets have a bluish tint that makes them slightly different and, more importantly, they can be branded. They can also be tagged for full RFI traceability.

Changes in requirements have been closely monitored by Autobar, ensuring the product gets to the consumer in the best possible state.

“This has given the product more life. Now it can be sold up to six days later to a consumer that also benefits from good all-round optics. Indeed, a hinged prototype product has been developed by Autobar and will be available shortly.

“A more traditional material that Autobar uses for the produce sector is APET. APET is glossy and transparent and is regarded as more environ-mentally friendly than other plastics. It has a growth rate of around 13%.

“EU legislation means that there is a lot of environmental pressure to change and, therefore, the PLA market will become more attractive and that will happen sooner rather than later.

“APET, OPS and PLA are materials that will be used increasingly in future innovation for food related containers, pre-prepared salads, vegetable salads and fruit salads.”

When it comes to protein products, the packaging materials used are far more refined. Cryovac has learnt to do more with less.

Because protein was a back store business for many years, people liked the feel of EPS. But, when the supermarkets chose to stop processing food and to develop the market for protein straight to shelf, they chose to stick with EPS.

This featured a barrier liner and was made by robust equipment on site and complemented by equally robust materials.

Over the years this process has been refined to take cost out of the pack. It started with materials that topped levels of 90 micron.

Further development brought the level down to 60 micron and, more recently, 45-50 micron. In contrast Cryovac is now selling 25-micron co-extruded barrier shrink anti-fog films. That will be hard to beat!

“Now the barrier foam tray is changing. Users are moving to other materials and other packaging formats,” says Leo Docherty.

“Not everybody wants EPS. They want to market the meat differently. They want the consumer to see the product from all the angles. With barrier foam you can only see it from the top.

“Major UK retailers now use barrier APET material because their customers can see product from the side. This trend is also evident in Germany where the PP barrier tray predominates for economic reasons.

“So the tray will increasingly become available in clear or colour materials to give the user a broader offer for its protein product. Today, many consumers want to see what they are buying.

“The whole market place is changing. There is a sudden need for new materials and different ways of presenting product… and that’s the greatest challenge for Cryovac on a global basis.

“We see two main avenues of development in the immediate future. The first is barrier shrink films offering excellent pack appearance with good optics, shrink and dependable anti-fog.

“The second is the refinement of MAP technology to ensure that any product looks and is as good on day six as it is on day one. Lengthening shelf life is not important in the UK but preserving freshness and product quality is key.”