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Putting packaging on the MAP

A look down the aisles of any major retailer will confirm consumers love a package with a modified atmosphere. For them, MAP spells out fresh, quick and easy with the accoutrements of an entire gourmet meal ready for the baking - or microwaving. For the plastics packaging industry MAP means BIG business.

“Modified atmosphere packaging will see tremendous growth over the next five years,” forecasts Pira International. “The market for flexible packaging in this sector is predicted to grow by over 11% per year and be 43 250t in 2006 in Western Europe,” it predicts in the third edition of ‘Flexible Packaging for the European Market’ due to be published shortly.

But MAP interest does not just affect film and thermoformed trays and bowls. Its tremendous take up has been manna from heaven for the thermoform, fill and seal suppliers, the vertical form, fill and seal machine builders, flow wrapper and tray sealer manufacturers. It is a technology that cuts across packaging engineering and its applications are seemingly multiplying every month.

MSI Data is due to update its MAP statistical review and huge increases on earlier numbers are expected. But even statistics from 1999 indicated its potential. From under 2,000M packs in 1993 the UK volume for MAP packs shot up to 2,809M in 1998, with growth rates steadily increasing from 5% a year in 1997 to 8% by 1998.

These figures are small beer now, according to most sources. Growth could be as high as 25% per year over the last couple of years, bringing the number of packs up to over 5000M.

The cooked meat sector has seen rapid expansion, especially in the thermoformed, fill and seal format. “We sell vastly more machines for bacon and cooked meats applications than fresh foods,” reports Multivac’s John Hutchen.

Peelability and sealability is the natural progression in keeping favourite sandwich fillers fresh in the fridge. Over the last two years Multivac has responded with a peel and reclose profiled lid thermoformed from the top web.

The pack prevents the contents drying out once the MAP has been released. “Performed on the Multivac R530, this pack required forming to extremely tight tolerances; the two webs had to be accurately married together,” says Mr Hutchen.

Meanwhile, retailers are forever looking to promote higher volumes. A recent initiative is the four-pack multipack of hams supplied by DeliCo to Sainsbury.

Premium honey cured and premium smoked ham is filled into four, individually sealed MAP adjacent formings, which are perforated. The 300g packs may be opened one at a time, preventing the cooked meat from drying out and encouraging larger pack purchases.

The pack’s ability to snap open easily, peel well, while giving consumers choice without contamination saw it win Silver in the Starpack 2001 awards.

The Multivac line on which it is produced is highly automated and includes a MR thermal transfer unit to print the use by codes on the metallised top web.

Another Multivac idea, shown at Pakex, allows a cost effective positive reseal without extending the base web very far. The peel tab is slightly extended and a series of holes are punched in the top web that seals to this area.A label is then placed over the top.

In use, the lid is peeled back from the seal, but a positive reseal is achieved by the label sticking through the holes to the bottom web. “At the same time the holes are not compromising the modified atmosphere; they are in the outer lip area,” explains Mr Hutchen.

On the fresh meat front John Hutchen points to a recent development on the beef mince market as an example of “continuing pressure to take costs out of the business. ”

MAP machines have become faster and cheaper to run. In turn, prompting an appraisal of tray formers over tray sealers.

Anglo Beef Processors (ABP) chose three Multivac R530s for its redesigned mince packs. The equipment runs at 100 packs/min. Richard Cracknell, managing director of ABP says: “The 500g pack is one of the most attractive for mince in the market. At the same time Multivac has come up with the lowest cost option. “

Technically the system is claimed to be very effective too. Previous gas analysis techniques have involved removing all the packs produced in one machine cycle and carrying out destructive tests to measure residual oxygen levels off line. Here, in line analysis saves time by assessing the gas level in the sealing chamber at every cycle. If results fall outside the strict specification an alarm sounds to herald the need for remedial action.

According to Samantha Penn, commercial manager at heat sealing machinery specialist Packaging Automation, the choice of ready made pack or the thermoform, fill seal route is “a question of volume”.

Her company confirms MAP’s current position. “It is perhaps the single most important development in food packaging of modern times, it’s the number one technique for shelf-life extension of everything from raw meat to cheese and fresh pasta to processed seafood.”

The company offers a wide range of equipment including the semi-automatic machines, like the PA182 and PA2016 up to the Vision 4000. As well as true modified atmosphere techniques or MAP-V, the company has developed the gas flushing MAP technique – MAP-F.

Using MAP-V the air is removed from the pack by pulling a vacuum and is replaced by a single gas or a mixture of gases. It can be either ordered in pre-mixed cylinders or mixed at the point of use with a gas mixing panel on the heat-sealing machine.

Packaging Automation’s chairman, Anthony Penn says the reason it was originally not incorporated into automatic machines was because of the time needed to perform the MAP operation, which negated the speed benefits of in-line automatic machines.

MAP-F was introduced by Packaging Automation in the early ’90s with the objective of bringing modified atmosphere packaging to volume producers of prepared foods. It is now incorporated into the Vision machines, the 182 and the 4000, which are used by many of food production customers who supply Sainsbury, Marks and Spencer, Asda and Tesco.

With MAP-F the ambient air in the pack is expelled by the force of the new gas mixture blown into the pack, explains Anthony Penn.

Compared to MAP-V there is a reduction in the time needed for the modified atmosphere to be achieved, and this speeds up the sealing process. It allows volume driven producers to use MAP without compromising output speeds to the extent they would with MAP-V.

The PA 2016 and Vision 4000 both have the safety features needed for high oxygen work – a technique where the oxygen content in a gas mixture is usually around the 80% part and always higher than 21%. Because oxygen is a combustible gas, strict food industry regulations insist the machine incorporates a sealed chamber into which the products are placed. High oxygen MAP is now widely used in the packaging of raw meat and fish.

One area that has not mapped out as well as expected is the ready meal sector. Based on the growth of chilled over frozen foods, ready meals were predicted to become a key area for MAP.

Samantha Penn believes that producers and retailers see extended shelf life as a double edged sword. Increased shelf life leads to reduced wastage and increased efficiency because producers can do longer product runs, but consumers may perceive long shelf life as equalling not fresh.

“Only a small proportion of ready meals producers use MAP. In the last 18 months less than 15% of equipment sold to this sector was capable of MAP and most of this was for MAP-F.”

Two areas where the heat sealing equipment company has seen greater success in MAP growth are ready made salads in bowls and raw meat/marinated meat products.

“More than two thirds of the equipment sold to the prepared salad sector is capable of MAP and the majority of this is MAP-F. On the other hand more than two thirds of equipment sold to the meat sector is MAP-V – less than 1% is MAP-F,” Ms Penn reports.

Although, MAP ready meals are beginning to show signs of life according to Michelle Jackson, business development specialist MAP at gas supplier Air Products.

“MAP ready meals have not moved as fast as expected but we are starting to see them increase now – in particular the chicken in sauces in trays and pasta dishes.”

She points to last year’s developments in gas flushed ready meals in heat sealed smooth walled aluminium trays. The latest success being the Geest patented valve technology that allows MAP packs to be placed in the microwave, without the pack having to be pierced. When the pack heats the valve opens and the quality of the cooked product is said to be much improved. It is understood that another company is currently developing a second technology.

“Poultry has shown a big growth as it has moved away from overwrapped products in MAP mother bags to gas flushed pre-made trays, and marinatedmeats are growing too as people are keen to try more ethnic foods,” she adds.

But the hot news is likely to be “a change to the ‘whole bird’ market. Instead of being overwrapped we will begin to see gas flushed whole chicken packs,” she predicts.

Meanwhile, “the biggest turn round is going to be in smoked salmon. Six or so companies are now getting into gas flushed packs containing a few slices. You can see the packs in Waitrose and Marks & Spencer, for example,” says Ms Jackson.

Stir fries make another popular MAP meal in both vertical, form fill and seal and bowls. “The transparent PP wok is a ‘brilliant concept’ providing real differentiation in the microwaveable meals market,” said the Starpack judges of the Silver winning Anson Packaging pack for Geest Prepared Foods.” The product is gas flushed

The MAP market has also been a key driver behind development of Sandiacre Packaging Machinery’s reciprocating motion machine launched at Pakex.

The TG350-RC machine, which accommodates pack widths ranging from 60 to 350mm, has been designed to pack high volume packs of arduous salad, for example, at high speeds in a diverse range of bag sizes and styles. Pillow packs of 200x300mm containing 100g of salad produce can be output at a rate of 100/min, claims the company.

Reciprocating jaw motion, which is at the heart of the design, delivers features such as constant film speed, thus better back and cross seals, consistent bag length, and reduced strain on the film.

“It is all about speed and seal integrity,” says sales director John Edmonstone. He reported that two machines have been on trial for the last three months. “One has been packing cress under MAP, a particularly difficult product.”

With the purchase of Rose Forgrove three months ago, Sandiacre can now offer MAP flow wrapping technology as well as vertical form, fill and seal equipment. “Key issue is seal integrity,” emphasised international sales manager of Rose Forgrove, Paul Field.

“The PC driven Integra has the capacity for the sealing time on the transverse seal to be dialled in. So even if you are running at say 40, 60 or 80 packs/min you can keep the seal time at say 0.2sec.”The latest application reportedly seeing growth is flow wrapping of British sausages.

Richard Tearle, Ilapak’s divisional manager horizontal form fill seal reports excellent acceptance of the company’s Delta 3000 LDR, its latest inverted, electronic flow-wrapper.

It is designed to produce hermetically sealed modified atmosphere packs at high speeds of up to 140 packs/min. “We have sold seven lines for ethnic bakery products in the last 18 months,” he adds.

Stacks of tortillas are particularly difficult to handle, but the three belt lugless infeed allows products to be transferred automatically onto the moving film to minimise product damage.A pressureless product accumulation conveyor is also available for more delicate products.

The film is fed into the machine from below the level of the product flow – this allows loose pieces to be placed directly onto the film, ensuring exceptional hygiene standards and efficient pack handling, added the company. High integrity sealing is effected by the simple sealing head, which has an ‘oval’ jaw motion profile.