Food safety in packaging: a retail perspective

Packaging Professional magazine
,
11 Nov 2013
Tin cans of food

Despite increasing pressures to address merchandising and environmental concerns, food packaging retailers cannot afford to let consumer safety take a back seat, argues Mark Caul, Technical Manager of Packaging at Tesco, UK. He examines food packaging risks and the associated legislation, and explains how companies can stay ahead of the game.

Food packaging is a necessary mechanism that allows retailers to deliver safe, hygienic food on a mass scale to an ever-increasing population. Packaging for food products has many functions - it is not just a carrier for the food, but provides tamper evidence as well as functionality, for example oven and microwave-proof packaging. It also retains food freshness, communicates ingredient and nutritional information, minimises food waste, protects food from contamination and imparts safety messages, such as allergen contents.

However, a less understood and perhaps taken for-granted aspect of packaging is its own risk to customer safety. The risks are both real and dangerous, and have been known to cause fatalities. These span everything from chemical risks (such as chemical migration into food) to physical hazards (such as bottle closures and metal can lids causing injury) to foreign bodies and tamper evidence. A food packaging team will ensure that a retailer steers clear of these risks, providing constant due diligence. To avoid this minefield, it is necessary to stay ahead of legislation – easier said than done at a time when the packaging industry is under increasing pressure to address environmental issues as well as squeeze costs.

An understanding of food packaging regulations is an absolute requirement for any retailer and particularly for a food packaging team. In Europe, the most important is the Materials and Articles in Contact with Food Regulation (EU Regulation 1935/2004), of which the equivalent in the USA are the FDA regulations. Extending beyond these are material-specific regulations, most notably the plastics regulations (2002/72/EU and its amendments). These specify the additives that can be used to manufacture the different plastic types and the quantities allowed. All these have been tested, approved for food use and placed on a positive list. Supporting the legislation are a number of packaging manufacturer hygiene standards (ISO EN 15593, ISO 22000 and BRC/IOP Global Standard), as well as an overarching Good Manufacturing Practice guideline. Together, these address a number of risks that can arise through food packaging.

Chemical migration
Chemical migration can occur from many different sources and across a wide range of material substrates, so much so that the Food Standards Agency (FSA) and the European Food Safety Authority (EFSA) has rolling programmes of investigation. Of particular note are chemicals in inks and varnishes, and those in plastic materials. The introduction of recycled content into plastic merited an in-depth study of risks, albeit led by retail in the absence of legislation.

Inks are manufactured from complex chemical recipes and the legislation governing their migration is equally complicated, due to the number of chemicals used and the fact that some are carcinogenic or genotoxic/mutagenic. While those known to be carcinogenic or genotoxic/mutagenic are legislated against, many chemicals have never had toxicity studies carried out on them, meaning that the effects of ingestion are simply not known.

Packagers must not only be vigilant on the sources and uses of inks and varnishes, but need to understand migration mechanisms from packaging. The risks from inks and varnishes were most notably highlighted in 2005, when a recall was put in place by Italy, France, Spain and Portugal due to the discovery of isopropylthioxanthone (ITX) in a branded cereal product. While it was clear that good manufacturing guidelines applied and no substances posing a health risk migrated into the food, the fact remains that at the time, ITX was not specifically regulated against by any kind of legislation. This demonstrates the importance for manufacturers and retailers to not simply rely on current legislation but to pre-empt it wherever possible (especially at a time when technology is advancing faster than legislation can keep up) to prevent potentially costly incidents such as this.

In 2009, the Belgian authorities imposed a product restriction as a result of unacceptable levels of 4-methylbenzophenone (4-MBP) and benzophenones in cereals, which affected UK retail. Both are used as photo-initiators for UV cured inks, but an animal study carried out by EFSA earlier that year had linked 4-MBP to carcinogenic effects. In this particular case, the inks printed on the outside of the pack migrated through the board and, in the absence of a barrier layer (such as plastic or aluminium coating) on the internal surface, migrated into the food.


Although ink manufacturers may refer to low-migration and low-odour inks (those with long molecular chains that limit the possibility of migration, but do not stop it), they will never claim that they are suitable for direct food contact use. Because it is possible for the ink to migrate via the vapour phase into the food, any application must be supported by migration studies and certainly only low-migration inks should be used.

Changes in legislation
Vigilance on legislative changes to overall and specific migration limits can make the difference between a legal or illegal product. Take the example of food products packaged in jars. Two chemicals are of concern here:

  • azodicarbonamide – a chemical present in the blowing agent of gaskets that decomposes to semicarbisides under high temperature (of particular concern for infant consumption of jar-packaged baby food)
  • epoxidised soybean oil (ESBO) – a plasticiser used in the gaskets of glass jars with metal lids that balances tight closure and easy opening


ESBO is an interesting example of how product and legislation changes can make an important difference between a pass and a fail. ESBO has been under scrutiny for its high migration, which results from the high ratio of gasket area in food contact. Oily products are particularly susceptible, with an almost complete migration transfer over a matter of weeks.

The overall migration limit for ESBO was set at 50mg/kg food, which was also the specific migration limit. However, the concern for infant products was such that a lower limit of 30mg/kg was set. This subtle but important change to legislation has serious implications for retailers selling baby foods.

To mitigate this, it is possible to implement a simple change in lid design that reduces the exposed gasket area. An understanding of the mechanism of transfer is important, as a simple product development that changes the gasket exposure area to the food can have a significant effect on the amount of chemical that migrates.

Physical risks
In addition to chemical risks, packaging can present a range of physical risks if not managed correctly. A retailer will respond to a wide range of customer injuries throughout the year and, although work is always ongoing to reduce the number of injuries, manufacturing tolerances, manufacturing error and customer behaviour mean that a zero injury target remains a distant aspiration.

Glass causes the greatest number of customer injuries in food retail, the primary source being wine bottles. It is vital to have a good understanding of the nature of glass defects as well as the glass manufacturing process, such as the importance of good annealing curves at the manufacturing site. In addition, an understanding of customer behaviour and the impact of good packaging design reduces the number of glass injuries.

As an example, glass wine bottles will have a tamper-evident plastic seal, which some customers will try to break using a knife. The impact on the rim of a bottle can cause a fracture initiation point, which will propagate to failure under the shear forces generated during cap removal, which can result in severe laceration to the hand. A simple design change, such as creating a coloured tear strip on the plastic seal, can steer customers away from using a knife to open the pack. This explains the reluctance of retailers to bow to the pressures of packaging reduction targets in this area, in particular on pressurised bottles such as champagne.

Glass is by no means the only culprit. Sharp edges on packaging such as biscuit tins, grocery cans (the corned beef can is a frequent source of injury) and indeed even plastic packaging such as yoghurt packs can inflict wounds. This is often the result of overengineered packaging that is difficult for customers to open, or poor manufacturing that leaves sharp edges and burrs.

Then there are burns and scalds to consider, caused by the likes of foil and plastic oven-safe trays, disposable barbecues, pyrex containers for hot desserts, and ceramic mugs retailed as part of food gifts such as Easter eggs. This diversity requires the packaging team to be familiar with a wide range of materials and understand the subtleties of food interaction and customer behaviour. Melting PET is a known issue that will remain at low levels of complaint until a material with a higher glass transition curve is developed. As such, knowledge of glass transition curves for plastics as well as oven variability will enable retailers to provide guidance for package labelling on oven ready meal products.

In addition, child safety should not be overlooked. A retailer can be prosecuted under the general safety directive for not understanding the risks its food packaging can pose to children. In essence, the law states that all reasonable precautions must be taken to ensure a product is safe, meaning that a retailer is responsible for risk assessments and, where possible, eliminating conceivable risks.

The risks for child injury are diverse, and some can potentially be fatal. The nature of these hazards can be choking, aspiration, laceration, insertion or chemical-related, or a combination of these. For example, a child will be attracted to a simple printed game on the back of a cereal box, be it for for play value or, in the case of the under-36-month age group, simply for its aesthetics. This younger age group will often mouth the packaging, thereby exposing themselves to the chemicals in inks as well as possible choking and aspiration hazards, as the paper/board will become wet and start to disintegrate.

Caps and closures are also common choking/ aspiration hazards for children, including sports caps on drinks. The importance of design that targets children came under close scrutiny in 2007 in the UK, when a shampoo bottle became subject of inquiry after the cap caused a child fatality. The bottle had been designed in the shape of a frog, the cap of which was smaller than the recommended 3.8cm diameter for choking hazards in children.

Another important risk to consider is the printing of face masks on packaging. Warning instructions for the use of scissors must be clearly stated on packaging of this type and, more importantly, the size of eye holes regulated under the child safety standard EN71. Too small a hole will restrict peripheral vision, which can lead to traffic accidents when children are crossing roads.

Beyond design
Even if the packaging itself is safe, what about the contents of the pack? Foreign bodies come in all shapes and sizes, from many different sources, and can stem from poor control of processes at manufacturing and packing filling sites, or indeed from farms producing ingredients for recipes.

The most common types are plastics, metal and insects. Sources of plastic foreign bodies include:

  • ‘angel hair’ and broken pieces of plastic from the packaging itself
  • blue polyethylene from bags used to transport food from the manufacturing site
  • small pieces of plastic from the land (most commonly found in produce packs)
  • blue plasters from workers on food manufacturing production lines
  • factory parts, such as plastic cleaning equipment, cable ties and machine parts


The good news is that all of the above is preventable, in particular through good training that develops understanding on systems for prevention, as well as mechanisms of failure such as environmental stress cracking.

However, even if a retailer does everything to ensure the packaging and its contents are hazard- free, the product has to stay that way until point of purchase if customer safety is to be ensured. Tamper evidence is becoming increasingly important, providing a method by which a product can easily be recognised as having been touched or opened either deliberately or by accident. It is important that retailers remain realistic and recognise that tamper proof is not achievable – instead, tamper evidence is the goal and for this there are many solutions, including inner seals and tabs, breakable caps and tabs, outer seals, shrink wraps and tear-away tabs.

The race against technology
Advances in packaging technology can sometimes move faster than supporting legislation. A case in point is food-safe recycled content in plastics that, although now commonplace in retail, was developed in the absence of relevant legislation.

The main challenge was an unhygienic waste infrastructure that reprocessed plastic packaging disposed of by the consumer into new food-contact packaging. While this was allowed as long as it was capped between virgin layers, lack of adequate legislation meant that packers and retailers were exposed to potential risks via uncertain mechanisms of migration through these capping layers – for example, pinholes and thinning of the capping layers at the corners of food trays. Legislation has since caught up with the loophole and new packaging regulations now exist that allow capping layers on post-consumer waste in plastics. However, the recycled content must be chemically clean, which is achieved using technologies such as high pressure and high temperature that drive off chemical volatiles.

The latest concern is legislation (or lack thereof) for the emerging nanotechnology applications for packaging. While that remains a pressing issue for legislators – and legislation will continue to become more complex, in particular in the arena of chemical risks – safety remains a critical function that the entire supply chain needs to be aware of.

Chemicals of concern

Aside from the substances mentioned earlier, it is important to be vigilant through horizon scanning techniques to monitor other potentially harmful chemicals, including:

  • novolac glycidyl ether (NOGE)
  • bisphenol-A diglycidyl ether (BADGE)
  • bisphenol-F diglycidyl ether (BFDGE)
  • bisphenol-A (BPA)
  • benzophenones and derivatives
  • phthalates and plasticisers
  • 1-methyl-2-propanol
  • aluminium, tin and heavy metals
  • primary aromatic amines
  • formaldehyde and melamine
  • mineral hydrocarbons

 

Standard studies

Both the FSA and the EFSA, which assess and communicate risks from the food chain to consumers, are currently undertaking an ongoing research programme into packaging.

It is important for a food's retail packaging team to be at the forefront of these programmes and, where necessary, replicate the research as well as interpret results to demonstrate due diligence and understanding of issues concerning human health. By doing so, a retailer can implement control of packaging by developing a quality management system that mitigates risk from packaging. The table below shows the packaging related study programmes carried out by the FSA in the last decade.

 

For more information, contact Mark Caul: markcaul@aol.com