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When a chemical from packaging migrated into baby milk products in four EU countries in 2005, Tetra Pak and Nestlé were hit with an estimated £1.7m bill to recall food packs over contamination fears.

However, that sum pales into insignificance against the total cost to a brand and the damage to consumer confidence in the way food is packed.

Isopropylthioxanthone (ITX) was in the ink used to print the rolls of material before they were converted into tetra paks. Once the inks were printed and UV-cured onto the carton, the material was rolled up for transport to the assembly point. Thus the printed outside came into contact with what would be the inside of the carton, and traces of ITX were transferred.

At the time, Nestlé spokesperson Francois-Xavier Perroud said: “This is a packaging issue not a food safety issue”, firmly denying that the public should worry about the health effects of drinking ITX-tainted milk.

“A lot of the problem was not that we knew that stuff was toxic, but that we did not know how toxic it was,” says Alistair Irvine, Pira Testing’s principal consultant in the analytical services division. He warns that managing a food safety incident without knowing all the facts can be very difficult.

Testing times
The Food Standards Agency (FSA) responds to any safety issues regarding food production, packing or vending, and issues alerts when incidents occur. The European Food Safety Authority (EFSA) tests packaging materials and sets guidelines for what is considered to be a tolerable daily intake (TDI) by humans of any chemical that comes into contact with food.

Rusty Odhiri, food contact materials consultant at the FSA, says the food packaging industry has a good safety record. “Scares rarely happen. But when they do happen, it becomes a big scare,” he warns.

He points to the FSA’s Annual Report of Incidents 2006, which shows that packaging plays a small part in food scares. Four incidents were reported in 2006 regarding chemicals leaching from packaging materials into food. Three incidents were the result of chemicals leaching from a can or tin and one incident was the result of chemicals leaching from cardboard packaging. The FSA dealt with 1,338 other reports of food contamination.

This doesn’t stop packaging-related food scares occurring. Remember the reports in 2005 that antimony continuously leached from PET bottles into the water they contained? Professor William Shotyk from the Institute of Environmental Geochemistry, University of Heidelberg, tested Canadian bottled water and said at the time that he would never drink water from a plastic bottle again.

Professor Shotyk’s stance was disputed by many sources. And the reaction of UK consumers showed they trust packaging and that, in convenient formats for popular products, scares wouldn’t deter them from buying a product. Euromonitor International reports that in 2006, more than 2bn PET bottles of water were sold in the UK, up from 1.9bn units in 2005.

There is already a wealth of data available from the EFSA on food-contact materials and a TDI limit has been set for most materials so that firms can test whether their products comply before putting them on sale. “Generally, in terms of plastic, the legislation is nearly complete. Most things have been assessed,” says Irvine. But he says adhesives, inks and additives are the areas food packaging companies should pay attention to in the future.

Tony Lord, an analyst in the chemical investigations division of Pira Testing, focuses on preventing tastes and odours seeping from a pack into a product. He agrees with Irvine that printing inks are a regular cause of food taints.

Ink issues
Barry Ferne, business development manager at packaging ink supplier Sun Chemical, says that most inks are not designed to food contact. “The general view to packaging is that inks are not intended for direct contact with food, although there are some available.

“We provide a range of food contact inks,” says Ferne, but there are some limitations. “They can be used for ordinary packaging, but they don’t have the brilliance and the lustre that people expect from ordinary inks.”

Odour taint, says Lord, often presents more of a problem. When a person opens a pack and smells something other than the food they are expecting, they tend to discard the whole thing without eating any. “That initial waft of a bad odour is enough to make them not eat that food,” says Lord.

“The number of particles needed to cause an odour is very small,” he says, and that quantity would normally be below the TDI limit, so, even if the smell was not off-putting to an individual, they would be unlikely to consume a harmful amount of any contaminated food.

Taints may not often cause harm to the public, “but they can cause millions of pounds worth of damage to a brand’s image and in recall costs,” says Lord. This should be encouraging to the public because “the industry takes a lot of care to avoid this,” he says, which can only mean safer food packs.

Lord says that “being able to take a structured view is important” when redressing an incident. In 2003 when semicarbazide was discovered in jars of baby food, the FSA admitted that “it now seems likely that semicarbazide does migrate into food from the plastic gaskets used to seal glass jars with metal twist-off lids”, but said “the information about how much of this substance can get into food is still extremely limited.”

Two years later, EFSA unveiled its conclusions on the matter, saying “it is not a concern for human health at levels found in food”, but that the food industry should find alternative methods for sealing jars as a precautionary measure.

This approach seems to be paying off in the UK as scares are rare, but a study in the US in July reported that there was a major threat to the quality of packaging materials from imports. The Toxics in Packaging Clearinghouse assessment of heavy metals in packaging found that 16% of the products tested breached legal toxicity limits. Many had come from the Far East.

Careless contamination
The safety alerts issued by the FSA in recent years show it’s not chemical contamination, but carelessness, that causes the most packaging recalls. HJ Heinz recalled a batch of its chicken and mushroom toast toppers in November 2006 because the packs had been incorrectly filled with the ham and cheese topping and the product was therefore labelled with the incorrect allergen information.

In June, Walkers withdrew a batch of six-pack prawn cocktail crisps after a quantity were filled with roast chicken flavour instead. This was classed as a packaging error because the packs would be labelled with the wrong allergen information. In July, ready salted crisps were mixed up with smoky bacon flavour and the packs labelled with the wrong allergen information as a result. And in April it was the turn of Wotsits Really Cheesy flavour snacks, when packs wrongly contained the Flamin’ Hot variety.

Also in April, Unilever’s Pot Noodle succumbed to packaging problems when a batch of plastic pots proved likely to develop cracks in the base or side wall. The firm quickly recalled the batch and has had no problems with production since.

All these incidents were addressed speedily because the food packaging industry knows how important food safety is to public health and to brand value. However, there are always new areas that need to be addressed and Odhiri from the FSA says EFSA has scheduled investigations into the safety of recycled plastic in food packs and it is likely to look at paper and board in the future.

In the meantime, the responsibility for rigorous materials testing must be shouldered by the manufacturer who can commission organisations like Pira to lighten the load.

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SAFE FROM HARM?
When 38 independent specialists in Bisphenol A (BPA) toxicity issued a statement on 2 August concluding that it “presents a clear risk to human health”, the debate on the relative food-safety of BPA in packaging re-emerged.

BPA has been an ingredient in epoxy-resins used to coat food cans and in polycarbonate, a rigid, clear, very strong plastic, since the 1950s.

In the 1930s it was investigated as a synthetic estrogen and it began to be considered by some scientists as a potential health threat to humans’ reproductive and endocrine systems.

Since then, it has been confirmed that BPA will leach out of plastic into food and liquids. But there are conflicting opinions about safety levels.

“BPA has always had limits set in food contact regulations,” says Dr Mercier Gick, senior advisor on industrial issues to the British Plastics Federation. “Because of concerns raised over leaching into tinned food and concerns raised on environmental aspects, the material came under the microscope.”

“It’s an emotive issue,” says Gick, since polycarbonate is used for packs like baby bottles and large water-dispenser bottles. However, she says the European Commission and the US Food and Drug Administration (FDA) agree that food contact products made with BPA are, and remain, safe for their intended use.

Gick says there is no problem as the amount of BPA that leaches into food is “very small. We’re talking parts per billion.”

With so little BPA contaminating food, packaging companies often feel there is no need to change the material of their packs, says Gick: “Commercially, there is certainly no alternative to BPA. The problem with substituting polycarbonate is that it has unique properties. It has a very high impact resistance – so high, it’s used for police protection shields.”

However, in some applications, BPA is no longer used in packs. “In tins cans, the amounts were, relatively speaking, a large small amount,” says Gick. “That’s where we find alternatives being put forward and used. That happened fairly rapidly. It was easier for firms just to act rather than try to judge the outcome of the debates.

“The real issue is, do very small amounts have the potential to cause harm?” she says. And at the moment, certain parts of the packaging industry are willing to trust the majority of the scientific community which believes that, in very low doses, BPA causes no harm to humans. “I have not seen or heard about major action being taken on the water bottle front. The alternative is a higher chance of the bottle breaking,” says Gick.

However, in the US at least, one retailer has taken action on BPA in its baby packs. “As of January 2006 we stopped selling baby bottle and child drinking cups made from polycarbonate plastic,” says Whole Foods Market.

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EUROPEAN REGULATION
The legislation that applies in the case of food safe packaging is the European Commission’s Framework Regulation 1935/2004, which states that food contact materials shall be safe and that they shall not transfer their components into the food in quantities that could endanger human health, change the composition of the food in an unacceptable way or deteriorate the taste and odour of foodstuffs.

It establishes 17 groups of materials and articles which may be covered by specific measures: active and intelligent materials and articles, adhesives, cork, rubber, glass, resins, metals and alloys, paper and board, inks, silicones, textiles, coatings, waxes, and wood. Separate specific measures exist for ceramics, regenerated cellulose and plastics.