MAPAX® – modified atmosphere packaging. The ultimate combination for freshness. Contents.

1. MAP – Modified Atmosphere Packaging 2. MAP – Benefits 3. MAP – Food grade gases and gas supply 4. MAP – Packaging materials 5. MAP – Packaging machines 6. MAPAX® – Packaging concept 7. MAPAX® – Best for meat and meat products 8. MAPAX® – Best for fish and seafood 9. MAPAX® – Best for dairy products 10. MAPAX® – Best for fruit and vegetables 11. MAPAX® – Best for dry foods 12. MAPAX® – Best for bakery products 13. MAPAX® – Best for prepared foods and catering 14. MAPAX® – Leak detection 15. MAPAX® – FAQs 16. MAPAX® – Glossary

Linde is a trading name used by companies within The Linde Group. The Linde logo and the Linde word are trademarks of Linde AG. MAPAX® is an EU-registered trademark of The Linde Group. Trademark registrations and their status may differ from one location to another. Copyright © 2017. Linde AG. → MAPAX® modified atmosphere packaging

MAP – Modified Atmosphere Packaging. Winning the race against time.

Nowadays, good food has to be healthy, spoilage endanger the quality and shelf-life of the minimally processed and attractively packaged – foodstuff. However, external factors also pose a as consumers’ expectations from foodstuffs are threat to the product’s freshness. It is therefore of continuously rising. Consequently, demands critical importance how the product is handled in on food producers and producers of packaging the processing stage, on the filling line or during machines and ma­terials are increasing, too. the chilling process prior to packaging. Particular emphasis must be placed on the packaging stage, The consumer of today reacts sensitively when because the way the foodstuff is packaged is it comes to artificial additives and always wants decisive when it comes to prolonging shelf-life to have the option of buying and preparing fresh and guaranteeing food safety for the consumer. foodstuffs and ready-made dishes that look and taste as if they have come directly from the farm or producer. Food safety and easy access to a The solution: modified atmosphere rich variety of foodstuffs are very important. packaging (MAP) Therefore, it is becoming more and more difficult to meet consumers’ high expectations. It is also In order to prevent this loss of natural freshness becoming clear that the time factor is crucial. and quality, an effective and intelligent concept of food preservation has been developed – MAP. By combining food-grade gases with the right The challenge: maintaining freshness packaging materials and machines, MAP can maintain the quality of foodstuffs and extend From the very moment fruit is picked, corn is their shelf-life. harvested or fish is caught, the race against time begins. From now on, natural deterioration and Deterioration processes and the role of gases

Food is a biological, sensitive commodity. Original Anaerobic microorganisms include Clostridium freshness and shelf-life are affected by the and Lactobacillus. When foodstuffs are handled inherent properties of the product just as much incorrectly, Clostridium can generate a toxin. as by external factors. Internal factors affecting Lactobacillus, on the other hand, is a harmless quality are: bacterium that turns the food sour by producing • The type and quantity of microorganisms lactic acid.

• Water activity aw • pH value • Cell respiration Low temperature is a highly effective • Food composition inhibitor

External factors affecting the inherent quality: Temperature is one of the most important factors • Temperature controlling microbiological activity. Most micro­ • Hygienic conditions organisms multiply optimally in the 20 to 30°C • Gas atmosphere range and show reduced growth at lower • Processing methods temperatures. Careful temperature monitoring is there­fore vital during all food handling and distribution stages. Chilling alone, however, will Spoilage starts immediately not solve all microbiological problems. There are some psychro­philic bacteria, e.g. Pseudomonas, It is primarily microbial and chemical/biochemical that multiply at relatively low temperatures. For deterioration that destroys food. Microbial such organisms, other measures such as modified deterioration starts immediately after harvesting atmospheres are more effective. or slaughtering. The presence of microorganisms can be traced back to the raw materials, the ingredients and the environment. Microorganisms are found everywhere in our surroundings, e.g. on Solubility in water at Pgas = 100 KPa gram/ our skin, on tools and in the air. For this reason, kilogram at 15°C good hygienic conditions must be maintained throughout the processing chain. The ways in which Carbon dioxide, CO₂ 1.97 microorganisms cause spoilage vary depending Argon, Ar 0.06 on the type of organism and the foodstuff itself. Oxygen, O₂ 0.04 Basically, microorganisms can be divided into two Nitrogen, N₂ 0.02 categories: aerobic and anaerobic.

Aerobic organisms require the presence of oxygen (O₂) to survive and multiply. Anaerobic organisms, on the other hand, grow in the absence of oxygen. Aerobic microorganisms include Pseudomonas, Acinetobacter and Moraxella, which spoil food by decomposing and producing substances that give a bad taste and odour. Oxygen causes chemical breakdown

The chemical reactions may be caused by oxidation of vitamins or lipids or by enzymes. The chemical breakdown of lipids is the primary process in dry or dehydrated foodstuffs and in high-fat fish. This is due to the oxidation of unsaturated fats in the presence of atmospheric oxygen, causing the pro­duct to turn rancid. Enzymatic reactions caused by polyphenol oxidase, for example, result in brown discolouration of sliced fruits and vegetables. Oxygen, however, is impor­tant in maintaining the red colour of cut meat.

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MAP – Benefits. Packaging solution for fresh herbs

A short story about long-term profits Extending the product range

The success story begins when a consumer decides Using modified atmospheres to extend shelf-life to buy. Which foodstuffs do they buy and which gives food suppliers the opportunity to widen ones do they refuse? And why? Tailored modified their reach and range by bringing new products atmosphere packaging (MAP) solutions are based to market. They can increase revenue by offering on consumer statistics and intensive market more products in the shops, e.g. fresh pizza or research geared towards actively preempting ready-made salads. consumer preferences and buying patterns. By packaging the foodstuff in a modified atmosphere, it is possible to maintain high quality and extend shelf-life by days or even weeks. Products that previously could not be stored fresh throughout the distribution chain can now be offered in shops without sacrificing quality. There are compelling economic advantages for food suppliers using MAP. This technology opens up new markets and simplifies distribution logistics for the successful promotion of sales and profits. High-quality shelf-life is extended when microbial deterioration is inhibited

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Increasing productivity, rationalising distribution

MAP simplifies all distribution logistics because scale companies. In some sectors, there are strong goods can be delivered less frequently and fluctuations in the availability of raw materials. For across longer distances. This enhances planning example, seasonal bottlenecks have to be bridged flexibility and rationalises the workflow from or peaks balanced. Food suppliers are challenged delivery of a raw material to transport of goods to ensure a steady stream of fresh produce at all to shops or distribution centres. Due to prolonged times. A predictable supply also allows them to shelf-life, food manufacturers are able to supply plan production more efficiently and ensure steady new markets with their goods and greatly extend utilisation of human and production resources. All their geographical sales region. This is another these factors increase the productivity and the important advantage when operating in a global efficiency of any company. market which is increasingly dominated by large- Higher availability, greater market share Reduced spoilage and returns

By using MAP, days if not weeks of high-quality Fresh food that is not sold in time is returned. shelf-life are gained during which fresh produce This is a large-scale problem that seriously remains available to consumers. Sales figures affects productivity. MAP makes it possible for soar with every additional day. As many big- products to maintain a safe level of quality. The name companies have proven, MAP results results are reduced spoilage and fewer returns. in successful product sales and raises market share. The bigger the market share, the more consumers react positively to the product. In addition to this, doing away with preservatives increases the sales volume and has a positive effect on the company’s image. Bacterial growth on pork in different atmospheres at +4°C

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MAP – Food-grade gases and gas supply. Scientists working in food packaging laboratory.

Matching supply modes to customer volume and pressure needs

Cryogenic vessel Cryogenic with high-pressure High storage storage vessel

Cryotank 200 HP Cryotank 200 (high pressure)

Medium Cylinder manifolds or manifold cylinder pallets (MCPs)

Gas consumption m³/month consumption Gas High-pressure compressed gas cylinders

Small cylinders Low 0 10 20 30 Gas application pressure requirement, bar

Names may vary from country to country. A gas supply adapted to every application

The gases predominantly used in modified “Food-grade gas” is a specific definition for gases atmosphere packaging (MAP) are carbon dioxide used as a processing aid and/or additive in order (CO₂), nitrogen (N₂) and oxygen (O₂). These gases to ensure that standards are complied with. are used either alone or in mixtures. The gas Linde‘s food-grade gases conform to food-grade properties and the interaction of gases with the regulations, e.g. the regulation (EC) 1333/2008 food ingredients, e.g. solu­­bility in the foodstuff, and regulation (EU) 231/2012 on food additives should be taken into account when choosing the within EU countries and the FDA guidelines in the gas or gas composition. USA.

Linde supplies the food-grade gases CO₂, N₂ and N₂ and O₂ are separated from atmospheric air. O₂ and other gases authorised for foodstuffs either CO₂ is ta­ken from natural wells or captured pre-mixed or as individual gases in cylinders under as a by-product of, for instance, fermentation high pressure. For higher volume needs, these processes (wine, beer) or ammonia production. gases can also be supplied as liquids in insulated Sometimes it may be more effective and practical tanks for subsequent mixing at the packaging to produce nitrogen on site using PSA (pressure machine. swing adsorption) or a permeable membrane plant. If a PSA/membrane system is used, a backup gas supply system is recommended. Careful evaluations ensure the perfect fit Thorough quality control of food gases

The best supply option depends on the type Before the cylinders are filled, they are of foodstuff, the production volume, the examined, checked thoroughly and pre-treated packaging line and also whether the gas is to if necessary. Each unit is regularly analysed to be used anywhere else in production. It may be check for cleanliness and the correct mixture preferable to have pre-mixed gases supplied ratio. In addition, various independent institutes if production is relatively limited or if a new regularly inspect gas equipment for compliance production facility is being started up. When with sterility requirements. production rates increase and various products are to be packaged, it may be more suitable and more economical to switch over to mixing gases on site. Then a mixer is used and the gases are Advantages for gas users supplied from cylinders, tanks or PSA/membrane systems. • Gas supply solutions tailored to volume and pressure needs Each application must be evaluated separately • Security of supply before deci­sions can be made regarding the • Constant quality assurance supply options and gas mixtures. For quality • Traceability from source to customer assurance, regularly checking the gas mixture • High standards in purity in the finished packages after sealing is recommended. Gas supply

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MAP – Packaging materials. Various packaging materials

Perfect food comes in perfect packaging.

Packaging materials are of decisive importance For example, they have to examine how to for food quality and shelf-life. Many sophisticated protect the product against quality deterioration packaging solutions have been developed to from microbial growth, oxidation or dehydration. prevent rapid deterioration caused by oxygen, light and bacteria or by foreign odour and taste Other factors that play a role in the decision substances that come into contact with the include the barrier properties of the packaging product. against oxygen, light and volatile substances, the water vapour transmission rate, transparency, Foodstuff manufacturers have to choose suitable sealing ability, anti-fogging properties, packaging designs and materials while also microwaveability and price. complying with legal requirements on packaging materials. Various material properties combined

Packaging materials used with all forms of modified atmospheres (with the exception of fruit and vegetables) should have high barrier characteristics. Polymers used include polyester, polypro­pylene, polystyrene, polyvinyl chloride, nylon, ethylene vinyl acetate and ethylene vinyl Permeability ratio alcohol polymers. These are usually laminated or coextruded with polyethylene, which comes N2 : O2 : CO2 into direct contact with the food and is the heat- 1 : 5 : 25 sealing medium.

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Abbreviation Basic materials Primary function Al Aluminium High barrier APET Amorphous polyester Rigidity, gas barrier CPET Crystallised polyethylene Rigidity, high temperature resistance, gas barrier terephthalate EVA Ethylene-vinyl acetate Sealing layers EVOH Ethylene-vinyl alcohol Gas barrier HDPE High density polyethylene Moisture barrier, rigidity, microwave capability, sealing layers LDPE Low density polyethylene Sealing layers OPA Oriented polyamide Gas barrier OPET Oriented polyethylene- High temperature resistance, flexibility, puncture terephthalate resistance OPP Oriented polypropylene Moisture barrier, flexibility, puncture resistance PA Polyamide (nylon) High temperature resistance, flexibility, toughness, partial gas barrier PAN Acrylonitrile Gas barrier PET Polyethylene Rigidity, partial gas barrier terephthalate (polyester) PP Polypropylene Moisture barrier, rigidity, microwave capability PS Polystyrene Rigidity PVC Polyvinyl chloride Rigidity, gas barrier PVdC Polyvinylidene chloride Moisture barrier, gas barrier

Research focuses on developing materials each layer having its own function. Different that can be produced and disposed of in an plastic materials can therefore be chosen and environmentally friendly way, as well as on combined to achieve: optimising the packaging material, so that the amount of material is minimised. One →→ mechanical strength development is the use of foamed materials in →→ water vapour barriers to prevent weight loss trays for more attractive presentation. Another and dehydration development is the use of re-sealable packets →→ gas barrier for sliced ham, cheese and similar products. →→ gas permeability The table above shows a list of some typical →→ anti-fogging properties (the inside of the materials used for product packaging. The material should have a surface that does not exact composition of the film is adapted to the allow the formation of water droplets, which individual product and to the type of package reduce transparency) required. To ensure that a modified atmosphere →→ sealing properties, i.e. capable of sealing will be retained during the lifetime of the into a tight package while retaining material package, several different plastic materials are properties even along the package seal. often combined into a multilayered structure, Examples of materials used with certain food products

Food Material Bottom Top Red meat, OPET/PE/EVOH/PE OPP/PE/EVOH/PE processed meat, XPP/EVOH/PE OPET/PE/EVOH/PE poultry, fresh fish EPS/EVOH/PE OPA/PE (XPP and EPS are injection-moulded materials) Sausages PA/PE Pizza, pasta, cheese OPA/PE PA/PE Dry products, coffee, milk powder Metalised PET/PE Chopped lettuce leaves OPP PS/PE OPA/PE

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Packaging of salad with flow-pack machine → MAPAX® modified atmosphere packaging

MAP – Packaging machines. Crisps packed on a vertical flow-pack

Packaging machines for individual products.

There are five main groups of packaging machines on the type of machine. In gas flushing, the that use modified atmosphere packaging (MAP) air surrounding the food inside the package is technology, depending on the type of product replaced by means of a continuous gas stream and type of packaging. Although these machines before the package is sealed. A continuous are based on different principles, the basic flushing process enables high packaging speeds. mode of operation is the same. First, a package In the vacuum process, air is extracted from the is formed (or prefabricated packages are used) package and the resultant vacuum is broken by and filled with the product. Then the air in the injection with the desired gas mixture. Since package is replaced by a modified atmosphere. this is a two-step process, it is slower than the Finally, the package is sealed. These three steps gas flushing method. However, because the air take place either manually or automatically. The is almost totally removed, the efficiency of this methods used to modify the atmosphere include process with regard to residual oxygen levels is gas flushing or vacuum extraction and then gas better than in the case of gas flushing. injection. The specific gas consumption depends Vertical flow-pack

A film is formed into a tube that is pinched together at one end and sealed over an injection pipe. The product is portioned out into the tube, which is then sealed at the other end and cut off. Gas is continually fed through the tube to purge the air. This machine is mostly used for powdered and bulk products such as coffee and peanuts as well as diced foodstuffs. Sometimes gas flushing may be necessary before packaging.

Horizontal flow-pack

The foodstuffs are fed into a horizontal flowing tube that is constantly formed by a packaging machine. The tube is sealed and cut off along both sides of the product. Gas is flushed into the resultant bag, purging the air. This equipment works fast and uses less complicated film material than a deep-drawing machine. Typical foods are bakery products, sausages, cheese, pizza and salad leaves.

Crisps packed on a vertical flow-pack

Tray-sealer machine

The tray sealer can be operated manually, semi-automatically (illustrated here) or continuously depending on production volumes. This machine can be compared to a deep-drawing machine, but the bottom trays into which the product is placed are ready-made and not formed during the process. Depending on the foodstuff and marketing requirements, a wide range of trays can be used with the tray-sealer machine. These machines are used for most food products, e.g. ready meals, salads, meat and fish.

Gas flow Gas analyser Deep-drawing machine

Film is heat-formed into a tray at a drawing station and the product is then added. Air is extracted, gas is injected and the loaded package is then sealed with a top film. This machine is suitable for foodstuffs such as meat, fish and prepared foods.

Vacuum chamber machine

The product is inserted into prefabricated bags or trays. The packages are placed in a chamber from which the air is extracted and the pressure is then equalised with gas. The packages are then sealed. This machine type is suitable for small, low-cost production volumes.

Bag-in-box sealing machine

Prefabricated bags are filled with the product. A probe is introduced into the bag and air is extracted. Gas is then fed in, the probe is removed and the bag is sealed. Such equipment is used for large packages of meat, poultry and fish, for example. Packaging of vegetables with flow-pack machine → MAPAX® modified atmosphere packaging

MAPAX® – Packaging concept. Food-grade gases in action

All-in-one, universal MAPAX solutions

MAPAX is Linde‘s tailor-made modified →→ the handling and processing of the product atmosphere packaging (MAP) programme →→ the types and quantity of microorganisms based on data relating to foodstuffs, gases and →→ the level of hygiene packaging. MAPAX takes the following factors →→ the delay before packaging into account: →→ the temperature →→ the properties of the packaging material, e.g. permeability →→ the free gas volume of the package →→ the gas mixture →→ the residual oxygen level MAP industrial infrastructure

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Combining experience, research and know-how for fresher food

In order to be able to recommend the right Linde works closely with food research institutes MAPAX solution for the application in question, in many countries, for example SIK (Sweden), VTT Linde acts as more than a mere supplier of gas. (Finland) and Campden (UK). In the laboratories MAPAX is based on close cooperation between of SIK, for example, various simulations are the suppliers of the packaging materials, the carried out to determine the potential hazards packaging machines and the gases. The purpose from microorganisms. Such studies provide of this collaboration between suppliers is to be the information necessary for determining safe able to meet demands for efficient and cost- shelf-life periods. Because Linde understands effective packaging of food­stuffs, with consistent how different bacteria are affected by the product quality throughout the entire distribution combination of temperature/atmosphere and chain and, ultimately, an attractive display other parameters such as permeability, it can in the chilled-food counter. By exploiting the offer a MAPAX solution that will ensure maximum advantages of MAP technology in the right way microbiological safety for each foodstuff. and by adapting methods to each application, solutions can also be offered to allow the manufacturer to develop new products for sale in new markets. Comparison of shelf-life for products packed in air and MAPAX

Food Typical shelf-life in air Typical shelf-life with MAPAX Raw meat 2–4 days 10–12 days Raw poultry 4–7 days 10–21 days Cooked meat/poultry 2–4 days 3–5 weeks Minced meat 24 hours 4–9 days Sausages 2–4 days 2–5 weeks Raw fish 2–3 days 5–9 days Cooked fish 2–4 days 3–4 weeks Hard cheese 2–3 weeks 4–10 weeks Soft cheese 4–14 days 1–3 weeks Cakes Several weeks Up to one year Bread Some days 3–4 weeks Pre-baked bread 5 days 4–6 weeks Cut salad mix (fresh) 2–5 days 5–10 days Pasta (fresh) 1–2 weeks 3–4 weeks Pizza (fresh) 7–10 days 2–4 weeks Sandwiches (fresh) 2–3 days 15–20 days Ready meals 2–5 days 7–20 days Dried foods 4–8 months 1–2 years Nuts 4–6 months 1–2 years

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Practical experience gives customers peace of mind

Linde has customers in the food processing have been established with several leading industry all around the world. Valuable contacts companies that package their products in modified atmospheres. Over the years, Linde has had the advantage of accumulating experience Cost of gas in relation to other factors of and know-how from application challenges for production which MAPAX has proved to be the answer. Collaboration with the food processing Gas machine package food industry has helped Linde to develop modified 1 : 5 : 10 : 100 atmosphere solutions to suit the widest variety of foodstuffs and packaging concepts. → MAPAX® modified atmosphere packaging

MAPAX® – Best for meat and meat products. Comparison of two different meat packages – one with modified atmosphere packaging and the other one without

Linde’s MAPAX® portfolio meets today’s food preservation challenges with bespoke gases and mixtures, application expertise and complementary installation, test and safety services.

Bacteria grow easily on fresh meat

Meat and meat products are particularly oxidation of the red pigment. The atmosphere susceptible to bacterial growth owing to their for fresh meat therefore normally contains high high water activity and nutrient content. Meat con­centrations of oxygen (60–80%) in order to is sterile to begin with, but when carved up, the retain the red colour by ensuring high oxygen surfaces exposed to ambient air provide excellent levels in the meat’s myoglobin. Highly pigmented conditions for the growth of bacteria. Minced meat such as beef thus requires higher oxygen meat is naturally even more exposed. For this concentrations than low pigmented meat such as reason, hygiene and effective temperature control pork. With the right mixtures, the practical shelf- in pro­cessing and prepackaging – keeping tools life of con­sumer-packed meat can be extended and equipment clean – are vitally important to from 2–4 days to 5–8 days at 4 °C. minimise the contamination of the product with microorganisms. The effectiveness of carbon dioxide

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Bacteria count over time for meat stored in air and in a modified atmosphere at the same temperature. The meat stored in air enters the period of extremely fast growth, the lag phase, well ahead of the meat stored in the modified atmosphere. This is because the CO₂ in the modified atmosphere has dissolved into the surface of the meat, reducing its pH value, inhibiting bacterial growth and thus extending the lag phase, until the point when the inhibiting effects become insufficient to control the bacteria.

Recommended gas mixtures for meat and meat products

Product Gas mixture Gas volume Typical shelf-life Storage temp. Product volume Air MAP Raw red meat 60–80% O₂ + 100–200 ml 2–4 days 5–8 days 2–3 °C 20–40% CO₂ 100 g meat Minced meat 80–100% O₂ + 100–200 ml <24 h 3–4 days 2–3 °C 0–20% CO₂ 100 g meat Raw light poultry 40–100% CO₂ + 100–200 ml 4–7 days 16–21 2–3 °C 0–60% N₂ 100 g meat days Raw dark poultry 70% O₂ + 100–200 ml 3–5 days 7–14 days 2–3 °C 30% CO₂ 100 g meat Sausages 20–30% CO₂ + 50–100 ml 2–4 days 2–5 4–6 °C 70–80% N₂ 100 g prod. weeks Sliced cooked meat 30% CO₂ + 50 –100 ml 2–4 days 2–5 4–6 °C 70% N₂ 100 g prod. weeks Poultry

Poultry is very susceptible to bacterial spoilage, bulk or master bags), 100% CO₂ is recommended. evaporation loss, off-odour, discolouration and In both retail and bulk modified atmospheres, N₂ biochemical deterioration. The sterile poultry is used as an inert filler gas. tissue becomes contaminated during the evisceration process. The practical shelf-life of gas-packed poultry is about 16 to 21 days. Meat products have different microflora The head-space volume should be nearly as large as the product volume. In con­trast to red Deterioration of meat products is most meats, poultry does not undergo irreversible commonly caused by microbial spoilage. Due discolouration of the meat’s surface in the to the processing operations, for instance presence of O₂. The spoilage of raw poultry is marinating, dry­ing, smoking, fermentation, mainly caused by microbial growth, particularly curing and cooking, the microflora in meat growth of the Pseudomonas and Achromobacter products differ from those in raw meat and the species. These aerobic spoilage bacteria are spoilage mechanisms are thereby different. very effectively inhibited by CO₂ in modified This affects the gas composition used in the atmosphere packaging (MAP). Levels of CO₂ package. In order to prevent the products from in excess of 20% are required to significantly going off, the concentration of carbon dioxide extend the shelf-life of poultry. Package collapse is usually low (20–50%). and excessive drip could be a problem for raw poultry, so if higher levels of CO₂ are used, the gas/product ratio should also be increased. Where package collapse is not a problem (e.g. Microbiological shelf-life of chicken at different atmosphere/temperature combinations







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MAPAX® – Best for fish and seafood. Linde’s MAPAX® portfolio meets today’s food preservation challenges with bespoke gases and mixtures, application expertise and complementary installation, test and safety services.

Fresh fish deteriorates very quickly

Fresh fish rapidly loses its original quality due to In order to maintain the high quality of fresh microbial growth and enzymatic processes. The fish products, it is absolutely necessary to keep sensitivity of fish and seafood is caused by its the temperature as close to 0°C as possible. In high water activity, neutral pH value (at which combination with the right gas mixture, shelf-life microorganisms thrive best) and the presence can be extended by a few important extra days. of enzymes which rapidly undermine both Provided, of course, there has been a continuous taste and smell. The breakdown of pro­teins by cold chain. Cod, flounder, plaice, haddock and microorganisms gives rise to unpleasant odours. whiting are ex­amples of fish that can be stored The oxidation of unsaturated fats in high-fat fish at 0°C twice as long in a modified atmosphere as such as tuna, herring and mackerel also results in air. in an unappetising taste and smell. Fish such as herring and trout can turn rancid even before microbial deterioration is detectable. Carbon dioxide: a prerequisite for maintaining quality

The presence of carbon dioxide is necessary to Depending on the storage temperature (0–2°C), inhibit the growth of common aerobic bacteria modified atmosphere packaging (MAP) prolongs such as Pseudomonas, Acinetobacter and shelf-life by 3 to 5 days compared with the shelf- Moraxella. This is primarily because CO₂ reduces life of raw fish in a tray with film over-wrap. the pH value of the product surface. The CO₂ Excessively high concentrations can produce concentration should always be above 20% and undesirable after-effects in the form of lost tissue can be as high as 50% to achieve the maximum liquid or, in the case of crabs, an acidic or sour shelf-life extension. taste. Recommended gas mixtures for fish and seafood

Product Gas mixture Gas volume Typical shelf-life Storage temp. Product volume Air MAP Raw fish 40–90% CO₂ + 200–300 ml 3–5 days 5–14 days 0–2°C 10% O₂ + 100 g fish 0–50% N₂ Smoked fish 40–60% CO₂ + 50–100 ml 15 days 30 days 0–3°C 40–60% N₂ 100 g fish Cooked fish 30% CO₂ + 50–100 ml 7 days 30 days 0–3°C 70% N₂ 100 g fish Prawns (peeled, 4% CO₂ + 50–100 ml 7 days 21 days 4–6°C cooked) 60% N₂ 100 g prod.

Quality loss in fish preserved in air and MAP

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Fish such as cod and plaice kept at 0°C can maintain their high quality for twice as long in the correct modified atmosphere. Oxygen keeps colour

Oxygen can be used as a component of a modified atmosphere to avoid colour changes and pigment fading in fish and seafood. The gas is also used to prevent the growth of anaerobic microorganisms such as Clostridium, which can produce toxins. However, the risk of Clostridium growth in fish with a short shelf-life packaged in the correct modified atmosphere is negligible. If the temperature is kept below 2°C, there can be no growth.

To combat rancidity, oxygen should not be used in packages of high-fat fish. Nitrogen is more suitable in such cases.

Importance of hygiene for a long shelf-life

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MAPAX® – Best for dairy products. Linde’s MAPAX® portfolio meets today’s food preservation challenges with bespoke gases and mixtures, application expertise and complementary installation, test and safety services.

Decomposition of dairy products Lactobacillus

Microbial growth and rancidity are the primary Lactobacillus, which is widely used in dairy causes of quality deterioration in dairy products. production, may also be a problem as it turns products sour by lowering their pH value. This The type of breakdown depends on the may be further intensified by the fact that characteristics of the particular product. Hard cottage cheese packages, for example, contain cheeses with relatively low water activity are incorrect gas atmospheres with excessive levels normally affected by the growth of moulds, of carbon dioxide. whereas products with high water activity such as cream and soft cheeses are more susceptible to fermentation and rancidity. The effect of 100% CO₂ on various bacteria

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Microorganisms are inhibited to varying degrees by carbon dioxide.

Mould prevented by carbon dioxide

In the packaging of hard cheese, carbon dioxide is the most effective choice. It effectively stops or reduces microbial activity and helps to retain texture. Even carbon dioxide concentrations of just 20% strongly affect the growth of mould fungi. Lactic acid bacteria, a natural constituent of cheese, are affected very little by the surrounding atmosphere. Soft cheeses are also packaged in atmospheres with increased carbon dioxide levels and low oxygen levels to inhibit bacterial growth and rancidity. In packaging for hard cheeses, the carbon dioxide level is up to 100%, and for soft cheeses, the level is usually restricted to 20–40%. This is to prevent the package from col­lapsing under atmospheric pressure as the carbon dioxide dissolves into the water content. Recommended gas mixtures for dairy products

Product Gas mixture Gas volume Typical shelf-life Storage temp. Product volume Air MAP Hard cheese 80–100% CO₂ + 50–100 ml 2–3 weeks 4–10 weeks 4–6°C 0–20% N₂ 100 g cheese Hard cheese, 40% CO₂ + 50–100 ml 2–3 weeks 7 weeks 4–6°C (sliced, grated) 60% N₂ 100 g cheese Soft cheese 20–60% CO₂ + 50–100 ml 8 days 21 days 4–6°C 40–80% N₂ 100 g cheese

Major cheese categories – moisture content

Cheese category Example varieties Moisture content (%) Unripened, soft Cottage not >80 Mozzarella >50 Ripened, soft Camembert 48 Brie 55 Semi-hard Caerphilly 45 Limburg 45 Hard Cheddar <40 Gouda 40 Emmental 38 Gruyère 38–40 Blue-vein Roquefort 40–45 Gorgonzola 40–45 Stilton 40–45

CO₂/N₂ mixes to avoid package collapse

Value-added cheeses, such as grated or products. The shelf-life of cottage cheese packed sliced cheddar, are also packed in modified under carbon dioxide can be exten­ded by a atmospheres. Grated cheese is usu­ally packed in week. an atmosphere of 50% N₂ and 50% CO₂. The use of nitrogen avoids package collapse. Nitrogen stops cream turning sour

Adding cultured products to the list Cream and dairy products containing cream rapidly turn sour in pure carbon dioxide Cultured products such as cottage cheese atmospheres. The gas is therefore replaced by were not packaged in modified atmospheres nitrogen or a mixture of nitrogen and carbon until recently. But the demand for longer life dioxide. By eliminating oxygen, nitrogen prevents has extended modified atmospheres to these rancidity and the growth of aerobic bacteria.

→ MAPAX® modified atmosphere packaging

MAPAX® – Best for fruit and vegetables.

MAPAX® is a registered trademark of The Linde Group. Linde’s MAPAX® portfolio meets today’s food preservation challenges with bespoke gases and mixtures, application expertise and complementary installation, test and safety services.

The permeability of packaging material Optimal equilibrium is vital The key to successful modified atmosphere A modified atmosphere must be combined with packaging (MAP) for fresh produce lies in the right packaging material to achieve optimum a packaging film of correct intermediary preservation of fresh fruit and vegetables. If the permeability. This enables a desirable equilibrium products are sealed in an insufficiently permeable modified atmosphere (EMA) to be established, film, undesirable anaerobic conditions (<1% O₂ where the rate of oxygen and carbon dioxide and > 2% CO₂) will develop with subsequent transmission through the pack equals the produce deterioration in quality. Conversely, if fruit and respiration rate. Typically, optimum EMAs of vegetables are sealed in a film of excessive 3–10% O₂ and 3–10% CO₂ can dramatically permeability, the modified atmosphere will leak increase the shelf-life of fruit and vegetables. out and moisture loss will also lead to accelerated deterioration in quality. Examples of materials that The EMA thus attained is influenced by numerous can be used for MAP of fresh produce (fruit and factors such as the re­spiration rate, temperature, vegetables) are microporous film or LDPE/OPP. packaging film, pack volume, fill weight and light. The respiration rate, in turn, is affected by the variety, size and maturity of the produce as well as the extent to which it has been processed. Consequently, determining the optimum EMA of a particular item is a complex challenge that can only be solved through practical experimental tests. Recommended gas mixtures for fruit and vegetables

Product Gas mixture Gas volume Typical shelf-life Storage temp. Product volume Air MAP Lettuce 5% O₂ + 100–200 ml 2–5 days 5–8 days 3–5°C 5–20% CO₂ + 100 g prod. 75–90% N₂ Fresh cut salad mix 5% O₂ + 100–200 ml 2–5 days 5–8 days 3–5°C 5–20% CO₂ + 100 g prod. 75–90% N₂ Fresh cut carrots 2–5% O₂ + 100–200 ml 2–5 days 5–8 days 3–5°C 15–20% Co₂ + 100 g prod. 75–83% N₂ Fresh herbs 0–5% O₂ + 100–200 ml 1–3 days 10–18 3–5°C 5–20% CO₂ + 100 g prod. days 75–95% N₂ Fruit salad mix 0–5% O₂ + 100–200 ml 1 day 3–6 days 3–5°C 5–20% CO₂ + 100 g prod. 75–95% N₂ Sliced apple 0–5% O₂ + 100–200 ml 1–2 days 8–12 days 3–5°C 5–20% CO₂ + 100 g prod. 75–95% N₂ Pineapple peeled, 5–10%O₂ + 100–200 ml 2–5 days 6–9 days 3–5°C cut 10–15% CO₂ + 100 g prod. 75–90% N₂ Pre-peeled 40–60% CO₂ + 100–200 ml 0.5 hours 10 days 3–5°C potatoes 40–60% N₂ 100 g prod.

Finding the right gas/packaging combination

The optimum MAP can be achieved by either compared with air packing. We offer practical sealing the produce in air or gas flushing with tests to demonstrate this for our customers‘ 3–10% O₂ and 3–10% CO₂ and 80–90% N₂. As specific produce. Different conditions may apply previously explained, modified atmospheres for peeled potatoes and apples, which should evolve within an air-sealed pack because of not be packed with oxygen because of enzymatic produce respiration. However, there may be reactions that bring about brown discolouration. circumstances when it is desirable to gas flush Pre-peeled potatoes, for example, can be packed so that a beneficial EMA is established more in 40–60% CO₂ + 40–60% N₂, prolonging their quickly. For example, the enzymatic browning of shelf-life from 0.5 hours to 10 days at 4 to 5°C. salad vege­tables can be delayed by gas flushing Classification of selected fruit and vegetables according to their respiration rate and degree of perishability in air and 3% O₂

-1 -1 a Respiration rate – CO₂ production (ml kg h ) Relative In air In 3% O₂ respiration rate at 10°C b Commodity 0°C 10°C 20°C 0°C 10°C 20°C in air Onion (Bedfordshire 2 4 5 1 2 2 Champion) Cabbage (Decema) 2 4 11 1 3 6 Beetroot (storing) 2 6 11 3 4 6 Low Celery (white) 4 6 19 3 5 12 <10 Cucumber 3 7 8 3 4 6 Tomato (Eurocross BB) 3 8 17 2 3 7 Lettuce (Kordaat) 5 9 21 4 6 14 Peppers (green) 4 11 20 5 7 9 Carrots (whole, peeled) — 12 26 — — — Parsnip (Hollow Crown) 4 14 23 3 6 17 Medium Potatoes (whole, peeled) — 14 33 — — — 10–20 Mango — 15 61 — — — Cabbage (Primo) 6 16 23 4 8 17 Lettuce (Kloek) 8 17 42 8 13 25 Cauliflower (April Glory) 10 24 71 7 24 34 Brussels sprouts 9 27 51 7 19 40 Strawberries (Cambridge 8 28 72 6 24 49 High Favourite) 20–40 Blackberries (Bedford 11 33 88 8 27 71 Giant) Asparagus 14 34 72 13 24 42 Spinach (Prickly True) 25 43 85 26 46 77 Watercress 9 43 117 5 38 95 Broad beans 18 46 82 20 29 45 Very high Sweet corn 16 48 119 14 32 68 40–60 Raspberries (Malling 12 49 113 11 30 73 Jewel) Carrots (julienne-cut) — 65 145 — — — Mushrooms (sliced) — 67 191 — — — Extremely Peas in pod (Kelvedon 20 69 144 15 45 90 high >60 Wonder) Broccoli (sprouting) 39 91 240 33 61 121

a mg CO₂ converted to ml CO₂ using densities of CO₂ at 0°C = 1.98, 10°C = 1.87, 20°C = 1.77. b Unless stated, produce is whole and unprepared. Respiration of fruit and vegetables

All living plants respire, i.e. different organic which involves a series of enzymatic reactions. compounds, mainly sugar compounds, provide The entire aerobic process can be described in energy to other life processes in the cells. This simplified form as: conversion of sugar to energy needs oxygen. Air contains 21% oxygen. When sufficient oxygen sugar + oxygen (O₂) → is available, the respiration is aerobic. If the carbon dioxide (CO₂) + energy + water concentration of oxygen drops, respiration becomes anaerobic. Anaerobic oxidation leads The respiration rate is measured as generated to intermediate products with undesirable ml CO₂/kg x hour or as used ml O₂/kg x hour. odours. Respiration is a compli­cated process

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MAPAX® – Best for dry foods. Linde’s MAPAX® portfolio meets today’s food preservation challenges with bespoke gases and mixtures, application expertise and complementary installation, test and safety services.

The key to keeping dry foods fresh The role of oxygen

Drying food to preserve it is a time-honoured Even small amounts of oxygen in food packaging practice. Everything from tea, coffee and may compromise quality and make dried products spices through milk and cocoa powder to dried impossible to sell. The oxygen concentration fruit and beans can be dehydrated to prevent thus has a major impact on the shelf-life. The spoilage. However, these dried foods still contain oxidation process can be effectively inhibited unsaturated fats of varying concentrations. This with a modified atmosphere, which involves makes them sensitive to oxidation and rancidity. replacing oxygen in the package with nitrogen, carbon dioxide or a mixture of the two. Packages containing particularly sensitive dry foodstuffs, such as powdered milk for babies, should have oxygen levels of less than 0.2%. As light can have a big effect on oxidation reactions, the modified atmosphere packaging (MAP) of dried foods should ideally also act as a light barrier. Recommended gas mixtures for dry foods

Product Gas mixture Gas volume Typical shelf-life Storage temp. Product volume Air MAP Instant tea 100% CO₂ 50–100 ml 5 days 20 days 20–25°C 100 g prod. Dry coffee N₂ or CO₂ 50–100 ml 4 weeks 24 weeks 20–25°C (ground) 100 g prod. Milk powder 100% N₂ 50–100 ml 12 weeks 52 weeks 20–25°C 100 g prod. Nuts 100% N₂ 50–100 ml 12 weeks 52 weeks 20–25°C 100 g prod. Crisps 100% N₂ 50–100 ml 5 days 20 days 20–25°C 100 g prod. Dry soup 100% N₂ 50–100 ml 5 days 20 days 20–25°C 100 g prod.

The role of water

Deterioration reactions in food are also influenced by water activity. This is not the same as water content. Water activity refers to the rate at which water becomes available for microorganism, chemical and biochemical reactions. It is defined as the ratio between the vapour pressure of a product and the vapour pressure of pure water under the same conditions. Hence a low level of water activity will help to prevent microbiological spoilage. Moisture also has a big impact on the appeal of dried snacks. Consumers expect their snacks to be crispy, which means the packaging must provide a barrier against water vapour. In the case of dried soups and instant drinks, water vapour is similarly problematic as it causes powders to clump and look unappetising. Here also, MAP with a moisture barrier can help avoid these undesirable effects. MAPAX for coffee – protecting valuable aroma and flavour.

Protecting form and flavour Perfect balance for dried foods

A modified atmosphere not only keeps dried fruit With MAPAX®, Linde has developed a range of and snacks crisp and fresh, it can also help protect modified atmospheres specifically to address the goods. The gas cushion forms a protective the challenges involved in preventing spoilage shield around sensitive products, making sure of dried foodstuffs. Our MAPAX application they reach the consumer undamaged. And in the engineers would also be happy to help you case of products such as coffee, where aroma run detailed tests to establish the optimum plays such an important role in the perception gas mixture and packaging properties for your and experience of the consumer, an impermeable dried foods. By optimising properties such modified atmosphere can help lock in flavour and as permeability, gas barrier and mechanical aroma. strength, you can extend shelf-life by valuable weeks and months.

→ MAPAX® modified atmosphere packaging

MAPAX® – Best for bakery products. Linde’s MAPAX® portfolio meets today’s food preservation challenges with bespoke gases and mixtures, application expertise and complementary installation, test and safety services.

Carbon dioxide slows mould growth on bread

The main spoilage factors for bakery products Modified atmosphere packaging (MAP) is are mould growth and chemical breakdown. especially suitable for rye bread, sweet bakery Fermentation may cause problems in filled bakery products and certain pies. For Danish pastries products. Since the water activity of bakery and other iced bakery products, excessive levels products is low, the growth of microorganisms of carbon dioxide can worsen the appearance of other than mould is seldom a problem. To reduce the icing by dissolving into the fat content and the risk of mould and spore contamination, very causing it to “melt away”. If the carbon dioxide good hygienic con­ditions are required, e.g. a clean concentration is balanced by nitrogen, the room. Mould is an aerobic microorganism, so it can product’s appearance remains unchanged. The be effectively controlled by carbon dioxide and loss or adsorption of moisture in bakery products low oxygen content, which subsequently extends is prevented by a barrier material. shelf-life by many valuable days. Recommended gas mixtures for bakery products

Product Gas mixture Gas volume Typical shelf-life Storage temp. Product volume Air MAP Pre-baked 100% CO₂ 50–100 ml 5 days 20 days 20–25°C bread 100 g prod. Cakes 50% CO₂ + 50–100 ml 15 days 60 days 20–25°C 50% N₂ 100 g prod. Fresh dough 50% CO₂ + 50–100 ml 3–7 days 18–31 days 5°C 50% N₂ 100 g prod. Pastries/ 30% CO₂ + 50–100 ml 7 days 21 days 20ºC doughnuts 70% N₂ 100 g prod. Sliced bread 50% CO₂ + 50–100 ml 2 weeks 2 months 20ºC 50% N₂ 100 g prod. Sandwiches 30% CO₂ + 50–100 ml 3–7 days 10–28 days 0–4°C 70% N₂ 100 g prod. Cream cakes 30% CO₂ + 50–100 ml 3–4 days 21 days 0–4°C 70% N₂ 100 g prod.

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 3URGXFW  (5+ 6WRUDJHWHPS 33UDUWEDNRGXFWHGEUHDG  (5+ 6WRUƒ&DJHWHPS 3)UXLWSLHVDUWEDNHGE UHDG   ƒƒ& )UXLWSLHV3DUWEDNHGU ROOV   ƒƒ& (5+3DUWEDN(TXLOLEULXHGUROOVP5HODWLYH+XPLGLW \  ƒ& (5+(TXLOLEULXP5HODWLYH+XPLGLW\ The importance of managing O₂ levels

Bread is a very porous product with a lot of effect mixes the modified atmosphere gas air bubbles inside it. Once it has been packed, with the air around the product. In the case of the air inside the bread and the modified flow-packers, oxygen levels are around 2–5%. atmosphere will balance each other out and Any concentration above that would have a the low O₂ content within the package will rise detrimental effect on the shelf-life. naturally by a few percentage points. The choice of machine has an impact on the O₂ level in the Thermoformers packaging and thus on the shelf-life. Horizontal Thermoformers can combine vacuum packing flow-packers and thermoforming machines with MAP. This flexibility enables further are typically used to pack bread in a modified reductions in the oxygen level. With many – but atmosphere. not all – breads, this enables manufacturers to extract as much oxygen from the packaging Horizontal flow-packers as possible. With both packaging technologies This packaging technology flushes gas into the (flow-pack & thermoforming), the modified packages to replace the air. This usually results atmosphere must be combined with the right in higher final oxygen levels because the flush packaging material to optimise shelf-life overall. A note on the staling process

The use of MAP has little or no effect on the most bakery products eaten cold are normally rate at which bakery products go stale. Staling stored at ambient temperature. For bakery pro­ is caused by starch retrogradation. Staling rates ducts eaten hot, such as pizza bases, the staling increase at chilled temperatures and therefore process is reversed during the reheating cycle.





 

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MAPAX® – Best for prepared foods and catering.

MAPAX® is a registered trademark of The Linde Group. Linde’s MAPAX® portfolio meets today’s food preservation challenges with bespoke gases and mixtures, application expertise and complementary installation, test and safety services.

Prepared foods – a challenge due to the Moisture and composition affect variety of ingredients deterioration rate

The deterioration of prepared foods varies Choosing the best CO to N₂ ratio for prepared considerably from one product to another. If meat food packages depends on the deterioration is one of the main ingre­dients, as in ravioli or processes that would otherwise limit shelf-life. lasagna, it spoils differently than, for instance, The composition of food and, most importantly, pasta. One major difficulty associated with the water activity determine the speed of prepared foods is the introduction of microbial microbiological growth, oxidation and enzymatic contamination during the manufacturing process. activity – as do the processing steps before This means that stringent demands are placed packaging. As a rule, the higher the level of on hygiene as well as on the raw materials water activity, the higher the CO₂ concentration during the production process. The most serious should be. breakdown processes are caused by the growth of microorganisms and by oxidation. In addition, The values in the table to the far right are affected bakery products sometimes go stale, leading by the use of modified atmospheres. As described to rancidity, discolouration and loss of taste. A in our “MAP - Modified Atmosphere Packaging” fresh pizza, for example, stored without modified flyer, the use of modified atmospheres provides atmosphere packaging (MAP) at 4°C to 6°C, spoils extra support in ensuring the safety of chilled food. in about a week. High quality can be maintained for some extra weeks by packaging the product in a modified atmosphere with a low oxygen concentration and high carbon dioxide level. In the case of pizza, the concentration of oxygen should be less than 1.5%. Recommended gas mixtures for prepared foods and catering

Product Gas mixture Typical shelf-life Storage Air MAP temp. Fresh pizza 30–60% CO₂ + 1 week 3 weeks 2–4°C 40–70% N₂ Fresh pasta 30–60% CO₂ + 1 week 3 weeks 2–4°C 40–70% N₂ Sandwiches 20–30% CO₂ + 3–7 days 10–28 days 2–4°C 70–80% N₂ Ready meals 30–60% CO₂ + 4 days 21 days 2–4°C 40–70% N₂ Fresh herbs 0–5% O₂ + 5–20% CO₂ + 1–3 days 10–18 days 2–4°C 75–90% N₂ Sliced onions 10–20% CO₂ + 1 day 4–6 days 2–4°C 80–90% N₂ Wraps 20–30% CO₂ + 2 days 6–10 days 2–4°C 70–80% N₂ Salad with 30% CO₂ + 70% N₂ 1 day 6–10 days 2–4°C chicken

Multi-component products have special demands

Each product in a prepared food represents a complex challenge. Particularly difficult are varied combinations such as sandwiches, filled pasta, salads, pizza and spring rolls. Since several different ingre­dients, each with its own special inherent properties, make up the pro­d­ uct, in-depth know-how is required to establish the right gas mixture that will best inhibit deterioration and maintain quality.

MAP is an important aid and safety measure, since prepared foods kept in the wrong environments can spoil very quickly, especially in the case of food products with a neutral pH value. Minimum growth conditions for selected microorganisms in chilled modified atmospheres

Type of microorganism Minimum pH Minimum aw for Minimum growth value for growth growth temperature Aeromonas hydrophila 4.0 na* 0.0°C Bacillus cereus 4.4 0.91 4.0°C Clostridium botulinum 4.8 0.94 10.0°C (proteolytic A, B and F) Clostridium botulinum 4.8 0.97 3.3°C (non-proteolytic E) Clostridium botulinum 4.6 0.94 3.3°C (non-proteolytic B and F) Clostridium perfringens 5.5 0.93 5.0°C Enterobacter aerogenes 4.4 0.94 2.0°C Escherichia coli 4.4 0.9 4.0°C Lactobacilli 3.8 0.94 4.0°C Listeria monocytogenes 4.4 0.92 –0.1°C Micrococci 5.6 0.9 4.0°C Moulds <2.0 0.6 <0.0°C Pseudomonas species 5.5 0.97 <0.0°C Salmonella species 3.8 0.92 4.0°C Staphylococcus aureus 4.0 0.83 7.7°C Vibrio parahaemolyticus 4.8 0.94 5.0°C Yeasts 1–5.0 0.8 –5.0°C Yersinia enterocolitica 4.5 0.96 –1.3°C na* = data not available Meeting the needs of the catering To reach the desired shelf-life and maintain industry the good quality of your pro­d­ucts, it is vital to keep constant control over both the product and The catering industry has always been packaging temperature. challenged to supply fine foods that are fresh and of the highest quality. Last-minute production is very often required to fulfil these Sandwiches packed using MAPAX demands. In most cases, this is an inefficient and very expensive way to operate. By using Preparing sandwiches is a complicated process Linde’s MAPAX® technology in your kitchen or where different items are placed on top of each production facilities, you will reduce stress to a other, for example brown bread with butter, minimum and be able to plan the coming days prawns, mayonnaise, lemon, lettuce, parsley or weeks of production even more effectively. and red pepper, or baguette with butter, ham, Well-organised food production coordinated cheese, lettuce and red pep­per, or brown with MAPAX technology will clearly improve bread with butter, smoked salmon, scrambled utilisation of human and production resources, eggs, lettuce and parsley. The individual items give you better control over purchasing influence each other because they provide and storage and extend your shelf-life. The different conditions for bacterial growth. By most common and beneficial way of using packaging in MAP, the shelf-life is extended by this packaging method in catering, hotel or 5 – 7 days if the product is packed in 30% CO₂ in restaurant kitchens is to get ahead of the “mise- N₂ at a storage temperature of 2–4°C. A typical en­-place” production. For example, if you slice packaging material is PA/PE. The use of MAPAX cheese and ham for the breakfast buffet on a technology for packaging sandwiches makes it daily basis, you can reduce this task to once or possible to prepare them in advance and thereby twice a week. The number of slices stays the reduce labour costs in the evenings and at the same, but you work more efficiently. This is also weekends, for example. true when preparing fresh meat cuts for the grill. Packing sandwiches and chilled food for out-of- hours service and other mar­ket segments is a cost-efficient and hygienic way of selling your produce. → MAPAX® modified atmosphere packaging

MAPAX® – Leak detection. MAPAX® LD for high-precision leak detection in all kinds of packaging.

Preserving freshness

Modified atmosphere packaging (MAP) is a can only be guaranteed if the package is correctly popular and proven way to preserve the quality sealed and intact. Consequently, leak testing is and freshness of foods on their way from the becoming an increasingly important part of end- field or producer to the retailer. They are also an to-end packaging concepts. It is the only way effective way to extend shelf-life in the shop – by for producers to ensure that every package that anything from days to months in the case of dried leaves the processing line is in perfect condition. foodstuffs. However, the effectiveness of MAP Wide spectrum of testing methods

There is a wide choice of methods available the production line. The ability to pinpoint single for leak testing. One of the most common is defective packages would eliminate the expense sampling, where random packages are selected involved in repacking or discarding entire batches. for inspection. However, this can be a costly approach as an entire batch may have to be discarded if a leak is detected. In addition, MAPAX® LD the random nature of sampling affords limited assurance overall. MAPAX LD is Linde’s innovative and accurate leak detection technology for high-speed, non- Integrated into the production line, in-line tests destructive in-line results. It uses a MAPAX gas provide more coverage and are much better mixture containing up to 4% hydrogen during the suited to highly automated food production packaging process. This does not affect the quality processes. Many food producers would welcome of food. A sensor in the machine instantly detects a leak detection method that is reliable, cost- the presence of hydrogen and triggers an alarm if a effective and fast enough to enable each package is leaking. The faulty package or packages package to be inspected without slowing down can be instantly removed from the production line and the rest of the batch continues as usual.

Benefits of MAPAX® LD at a glance

→→ In-line detection and removal of faulty packages →→ Higher productivity, less downtime →→ Cost savings due to reduction in rejects →→ Enhanced customer experience with consistently high quality levels →→ Low-maintenance design

MAPAX LD machine, side view Looking ahead

The only way to meet rising demand among and Critical Control Points (HACCP) concepts in retailers and consumers for fresh, perfect compliance with EU regulation 852/2004 on the foodstuffs of consistently high quality is to hygiene of foodstuffs will most likely rely more tighten control over sub-standard packages. and more on gas-enabled, in-line leak detection Leak detection will increasingly be viewed as concepts such as MAPAX LD as they are the most a critical control point in the food production reliable and flexible way to identify, evaluate process. Effective, future-proof Hazard Analysis and mitigate risks to food safety. Need to tackle food waste

Experts estimate that up to one third of food Both producers and retailers are challenged is wasted globally every year. In the EU, a to find effective ways to meet consumer significant – if not the largest – block of wastage expectations for cosmetically perfect food while occurs during food/drink manufacturing also reducing waste-induced costs by preventing processes and at the retail/wholesale stages. food from spoiling.

Per capita food losses and waste (kg/year) at production and consumption stages, in different regions

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MAPAX®. FAQs. Gas.

Which gas mixture should I use? If I use more gas, will using individual cylinders It depends on the type of food you produce, the become more expensive? shelf-life you need and the way your product Yes. As your business grows, so will your gas is consumed. For detailed information, refer to consumption. It is important to consult your local the specific MAPAX® flyers and your local Linde Linde representative to work out the best time to application engi­neer. Tests will probably need to switch from cylinders to a bulk tank supply mode. be conducted to decide the optimum mixture. What about safety for the use of gases? I am just starting out with the MAP system. We provide safety information and training. Each What equipment do I need? country has its own safety regulations for the use Most systems require a minimum of a regulator, a of gas. These regulations must be followed and flowmeter and piping. It is recommended to start integrated into your quality systems. Our specially with the pre-mixed single cylinders. Contact your trained experts will support you here. local Linde appli­cation engineer to see what else might be needed. What precautions should be taken when using gas mixtures with a high oxygen content? Is it better to purchase pre-mixed cylinders or Please contact the machine supplier to check to purchase pure gases and mix them on site? whether the machine is suitable for operation This depends on the volume and the type of with mixtures containing high oxygen levels. production at your facility. If the volumes are The machine has to be specified for high oxygen large or your plant produces various products ratings. with different gas requirements, it would be better to mix the right gases on site. What are the functions of different gases? The most important gas is CO₂, since it delays Where can I place the cylinders that I am the growth of microorganisms by dissolving into using? the food. N₂ is used to replace O₂ and thereby Ideally you would want them out of the pro­ decrease deterioration. It is also used as a buffer cessing area for quality and hygiene reasons. gas. O₂ is used to keep the red colour of meat and Please refer to your local regulations. for the respiration of fruit and vege­tables. The gases are normally used in mixtures to suit the How much pressure do I need to supply to my needs of the specific product. machine? This depends on the type of machine and the Why should I use food-grade gases? type of product being run. Consult your machine Industrial gases do not meet the legal demands manufacturer as well as your local Linde relating to the quality, traceability, labelling and application engineer. handling of food-grade gases as additives. Food.

How far can I extend the shelf-life of my Can I freeze a product that is packed in a products by using an MAP system? modified atmosphere? That depends on many factors such as food Yes- but it would be more effective and efficient product, temperature, hygiene, package and gas to first freeze the product and then pack it in a mixture. Generally, shelf-life can be increased by modified atmosphere. Make sure the packaging a period ranging from days to se­­ve­ral weeks. For material is suitable for freezing. specific information, see the MAPAX booklet for your particular product. Which gas or gas mixture can prevent the greenish colouring on the ham I produce? This greenish colouring is caused by bacteria grown naturally during processing. There is no gas or mixture that can change this afterwards. The meat I pack under MAP loses its colour, can result in drip inside the package. Adding but the colour reappears after I open the nitrogen should minimise the problem. package. Am I using the right gas mixture? The myoglobin molecule, which is responsible When I open the food package, I can smell a for the colour of meat and meat products, specific odour. How can we explain this? In most turns different colours with different gases. For cases when food is properly stored, this is a recommendations relating to the correct gas normal phenomenon. Each product generates mixture, see the flyer “MAPAX – Best for meat its own odour which consists of many volatile and meat products”. compounds that collect in the headspace of the package. Wait a minute after opening. If The sliced meat product I pack under MAP the smell continues, please check the quality turns grey. Sometimes only spots on the meat further. have different colours. Could that be caused by a wrongly filled gas cylinder, or is it Which gas or gas mixture should be used for caused by the gas mixture in general? the ripening of meat? The gases and mixtures in our food-grade Meat can be successfully ripened in mixtures of gases are controlled constantly and the wrong CO₂ and N₂. The mixture depends on the type of labelling or filling of a cylinder is almost meat and how it is cut. impossible. The grey spots may be caused by a number of factors. To give you just a few There are some pale grey, almost white spots ideas: the UV filter of the films could have been on smoked sausages. The sausages are rinsed, changed so that it no longer matches the light cooled in a cryogenic freezer and then packed exposure, additives could have been changed, in MAP. How can I prevent this? or the process could have been altered. Even There may be a number of reasons for these raw materials like water and meat can vary. spots, for example, a local low temperature area Maybe the optimum gas mixture is not being could arise during the cooling process that often used, or there is an excessively high residual comes before the slicing. Cryogenic freezing oxygen level in the package or condensed water involves very low temperatures that can cause that can fall down from the lid. Contact your bleaching. Contact your appli­cation engineer to local Linde engineer for tests. check the freezer. Changes in various steps of the process may influence this. Why does drip loss appear in fresh meat in a modified atmosphere? Drip loss is caused by meat handling and processing. Carbon dioxide and oxygen are absorbed and metabolised by the product and microorganisms, creating a partial vacuum inside the container. In fresh meat packaging, this vacuum may be strong enough to actually squeeze water from the meat if insufficient nitrogen is present in the headspace. This Packaging.

Does the package labelling have to indicate Why do MAP packages collapse? that the produce is packaged in a modified This is a normal physical phenomenon that often atmosphere? happens to products with a high water content. That depends on regional regulations. For EU CO₂ is a basic compound in MAP mixtures and countries, if the durability of a food has been dissolves easily in the water and fat phase of a extended by being packaged in a modified product kept at low temperatures. That’s why atmosphere, the packaging must state: the amount of CO₂ in the head-space decreases “Packaged in a protective atmosphere”. and creates a small degree of underpressure inside the package. What headspace (gas volume) is used in the package? How do I know that I have the right gas That depends on the food product and type of volume and mixture in the package? package. The gas volume / product volume ratio There are several types of gas analysers on lies between 0.5 for sausages and 2 for fish. the market. They are easy to use and will give you fairly accurate answers to questions about I get condensation in my package – mixtures and residual O₂ levels. It is important what’s wrong? to establish good routine checks to make sure The most likely reason is the temperature you do not package a large amount of produce difference between the product and the storage and end up with a less-than-optimum outcome. temperature. We can improve packaged product Your Linde application engineer will assist you visibility by using anti-fogging films. The product by advising on the mixture and equipment best should always have the lowest possible tempe­r­ suited to your needs. a­ture at the moment of packaging and be kept at the same temperature or lower during sto­r­age. Why does the residual oxygen in the package The package could also be punctured. Check the increase over time? residual oxygen. There are a few reasons why this might hap­ pen. There could be a leak in the package or My packages inflate over time. Is the product the oxygen barrier may not be high enough. fermenting? Moreover, air (containing 21 % oxygen) could This is nearly always due to the CO₂ which is have been trapped within the product during generated by the product. This can be caused packaging (cakes and breads for example). by too high tem­peratures (exceeding 4°C) over However, the most common reason is leaks in a certain time. This process cannot be reversed the sealing. by coo­l­ing the product down again. Some products, such as hard cheeses, develop CO₂ How much residual oxygen is recommended in through natural fermentation; this process can the package? sometimes continue after packing and cause an This depends very much on the product. Consult undesirable inflated effect. The package can also your local Linde application engineer. be contaminated and develop unwanted gases which cause it to expand. Check immediately with your food lab. → MAPAX® modified atmosphere packaging

MAPAX®. Glossary. Active packaging BIOGON® Active packaging employs a packaging material BIOGON® is the trademark for food-grade gases that interacts with the internal gas environment from Linde available in certain countries. to extend the shelf-life of food. Such technologies continuously modify the gas environment (and CA may interact with the surface of the food) by Controlled atmosphere. removing gases from or adding gases to the headspace inside a package. Examples of active Campylobacter packaging systems are oxy­gen scavenging, A genus of microaerophilic bacteria, some forms carbon dioxide production, water vapour removal, of which can cause serious health issues. ethylene removal and ethanol release. Carbon dioxide Aerobic organism CO₂ has a slightly acidic odour. It dissolves easily An organism that normally grows in the presence in water and thereby inhibits the growth of many of air (20% oxygen). microorganisms. Air contains approximately 0.03% carbon dioxide. Anaerobic organism An organism that normally grows in the absence Catalyst of air (20% oxygen) or oxygen. Anaerobes can A substance that regulates the rate of a chemi­cal be “strict” (obligate) anaerobes, i.e. they can be reaction and itself remains unchanged. killed by oxygen, or “facultative” anaerobes, i.e. they can grow under either aerobic or anaerobic Clostridium conditions. A genus of bacteria classified as gram-positive rods, anaerobic endospore formers with a Anti-fogging properties fermentative mode of metabolism. Film manufacturers produce a high surface tension film with hydrophilic properties that Controlled atmosphere allows moisture to wet the surface in order to The atmosphere surrounding food is changed and avoid fogging. then controlled during storage.

Argon CFU Ar is an inert gas with low solubility in water. Colony-forming units are used to measure the Air contains approximately 1% argon. number of microorganisms.

Bacteriostatic effect EMA Capable of inhibiting bacterial growth without Equilibrium Modified Atmosphere. killing microorganisms. Enzymatic reaction Biochemical process Chemical reactions catalysed by enzymes. Process or phenomenon in a living organism or biological system described in chemical terms. Enzyme MAPAX® Globular protein that is the catalyst of a biological MAPAX® is a tailor-made MAP solution developed system. and delivered by Linde based on data about food, gases and packag­ ing.­ ERH Equilibrium Relative Humidity. MAPAX LD In-line leak detection system from Linde. Fermentation Anaerobic energy-yielding metabolism of cells. Master-pack Consumer packages (over-wraps) are packed in a Gas flushing big flexible pack that is gas-flushed. Flushing with gas or gas mixture to establish a modified atmosphere. Membrane A membrane consists of numerous layers of HACCP very thin polymer film, bundled into fibres. It is Hazard Analysis and Critical Control Point. used to produce nitrogen on site by exploiting A systematic approach to the identification, the variations in velocity at which different gas evaluation and control of food safety hazards. molecules pass through polymer materials.

Inert gas Mesophilic bacteria A gas that does not react with other substances Organisms living in the temperature range around under normal temperatures and pressures. that of warm-blooded animals. This means those that grow well between 20°C and 45°C. Lactic acid bacteria Gram-positive bacteria, usually non-motile, Microorganism non-sporulating bacteria that produce lactic All microscopic forms of life, which includes such acid as a major or sole product of fermentative forms as bacteria, fungi, viruses, protozoa and metabolisms. All rod-shaped lactic acid bacteria algae. are placed in one genus called Lactobacillus. Modified atmosphere Leak detection An atmosphere differing from that of normal air. Quality assurance method to check whether food Normally the oxygen content is reduced and the packages have leaks. carbon dioxide content is increased.

Listeria Mould Facultatively anaerobic bacteria causing serious Aerobic food-spoilage microorganisms. They human disease. tolerate low water activity and a low pH value.

MAP Myoglobin Modified Atmosphere Packaging. This means The principal pigment in fresh meat. The form it altering the composition of the atmosphere inside takes is of prime importance in determining the a package so that it differs from that of normal air. colour of the meat. Nitrogen Psychrophilic bacteria N₂ is an inert gas with low solubility in water. Air These bacteria are able to grow at low contains approximately 78% nitrogen. temperatures, i.e. 0°C to 5°C.

Nitrous oxide Rancidity N₂O dissolves easily in liquid. It is mainly used Oxidation of lipids. for whipping cream. Respiration Nutritional content Aerobic energy-yielding metabolism of cells. Expresses the nutritional content, e.g. carbohydrates, fats, proteins and vitamins. Shelf-life The period between packaging a product and Oxidation its use, during which the quality of the product Chemical reaction with oxygen resulting in remains acceptable to the consumer. unwanted changes, e.g. rancidity and vitamin loss. Shelf-life technology The methods for enhancing shelf-life. Oxygen O₂ is a very reactive gas with low solubility in Sous-vide water. Air contains approximately 21% oxygen. The sous-vide technique entails packaging a food product in a vacuum, then preparing it at pH value high temperature (70 to 80°C), and quickly Expresses acidity (pH 0–6), neutrality (pH 7) and chilling it down to 2 to 4°C. alkalinity (pH 8–14). Thermophilic bacteria PSA Organisms that grow at elevated temperatures, Pressure swing adsorption. This technology is i.e. above 55°C. used to produce nitrogen on site. It is based on the ability of activated carbon to capture Water activity and retain oxygen from the air under certain aw. The ratio of the water vapour pressure of a conditions, while allowing nitrogen to pass material to the vapour pressure of pure water at through. the same temperature.

Protein Macromolecules built up of amino acids with peptide bonds.

Pseudomonas A genus of an aerobic gram-negative rod-shaped bacteria, ecologically important in soil and water owing to their large capacity to mineralise organic matter.

Phone +49 31001-0, 89 Phone www.linde-gas.com Gases Division, Carl-von-Linde-Strasse 25, 85716 Unterschleissheim, Germany Linde AG

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