Dr Ulrich Nehring, a food chemist, sheds light on the packaging materials that can help manufacturers ensure food safety
There are many different paths through which pollutants can find their way into food. That is why manufacturers have a control chain running through all the stages and levels of production—starting at the farmer with the control of feed, fertiliser and seed, through the analysis of raw materials such as milk, grains or vegetables, and on to control of the end product.
"Babies and infants are among the most sensitive consumer groups since their body weight is low, and their nutrition often does not have the variety consumed by older children and adults. Special demands are therefore placed on the safety of baby food," says Dr Ulrich Nehring, food chemist and former Scientific Director of Institut Nehring (now Eurofins). "Safety limits for potential pollutants in baby food are therefore often lower than for other foods," he adds.
To be able to meet these strict demands, raw materials from a specific, controlled production facility are usually used for baby food. The use of pesticides on fruit, vegetables and grains is largely avoided. Meat is obtained from animals which, if at all possible, have been reared without the use of veterinary medicines.
All the raw materials are thoroughly analysed before they are used, and the emphasis is put on tests for environmental contaminants such as heavy metals or dioxins. Analyses are also made for pesticide and veterinary medicine residues.
Dr Nehring explains: "Particularly tight hygienic standards are followed when processing the food. Tests are carried out regularly to exclude the possible presence of potentially harmful microorganisms, and also to avoid the inclusion of disinfectants or substances such as softeners or lubricants that might be transferred to the food from production equipment."
Equally, the packages that are used for baby food and other foodstuffs are checked for any possible material migration before being used. "The packaging may only be used if these strict, statutory limits are observed," says Dr Nehring.
Dr Ulrich Nehring
Another set of tests is finally carried out on the fully manufactured, packed food. "For example, additional analyses are carried out for softeners and mineral oil hydrocarbons that could originate from production equipment or the packaging," he adds.
The evaluation criteria of a range of tests pay attention to PVC/PVDC chlorinated compounds in lid seals, and their presence is deprecated. In practice, consumers—parents in particular—react badly to pollutants in packaging.
Dr Nehring explains: "These materials sometimes contain substances that can migrate to the packed food and thus find their way into the organism."
Current regulation—Food contact materials (EC) 1935/2004—specify that these materials "must be sufficiently inert to preclude substances from being transferred to food in quantities large enough to endanger human health or to bring about an unacceptable change in the composition of the food or a deterioration in its organoleptic properties".
Dr Nehring admits, however, that the process we know as migration frequently does take place.
"Exchange of material is always unavoidable whenever two materials—the packaging material and the food in this case—come into contact," says Dr Nehring. "Substance migration is therefore always present whenever food is contained in packaging or comes into contact with objects such as crockery or cooking utensils."
There are substances in practically all packaging materials that can migrate to food. Whether the material concerned is a "contaminant" usually depends on the quantity of this substance that a person absorbs.
Dr Nehring explains: "The law respects this natural circumstance, and requires that such a substance is restricted to quantities that are not hazardous to health, does not unacceptably change the composition of the food, and do not disadvantageously change the appearance, taste or odour of the food."
Good manufacturing practice must be applied to food packaging both by the manufacturer of the packaging—as well as by whoever fills the packaging with food—to limit any possible migration of substances out of the packaging to the minimum degree that is technically possible.
Manufacturers are thus legally obliged to adapt their processes continuously to the latest technical developments.
For the sake of health and its protection, the statutory requirements for packaging lay down strict limits for substances in packaging that, due to their properties, must only be consumed through food in limited quantities.
"This applies to many heavy metals, and to a large number of substances that are necessary for the manufacture of plastics," Dr Nehring explains. It also includes certain softeners along with vinyl chloride, which is the raw material for PVC. For Dr Nehring, "packaging materials must be regularly examined to see that they are keeping to these limits".
The legislative authorities are constantly editing and supplementing the list of threshold values on the basis of new scientific discoveries. The statutory regulations for plastics that are intended to come into contact with food have a list of about 900 substances that may be used for the manufacture of these plastics.
There is a specific migration limit for the great majority of these substances. This is a threshold value that must not be exceeded after substance migration into food. Regulatory authorities around the world determine for each substance a specific migration limit based on the absorption features. Plus each substance might be absorbed by a different quantity.
For example, the European Food Safety Authority (EFSA) determined a TDI (tolerable daily intake) for nickel of 2.8 micrograms per kg body weight; for mercury of 1.3 micrograms per kg body weight; and for chromium of 0.3 mg per kg body weight.
The EU regulation PIM 10/2011 determined an overall migration limit from packaging into food with 60 milligrams per kg of the food.
Dr Nehring explains: "Today there are various classes of substances that are found in packaging materials and for which an adequate scientific basis for the specification of reasonable statutory threshold values is not yet available. This includes mineral oil hydrocarbons (MOSH/MOAH) as well as certain hormone-mimicking substances."
For Dr Nehring, "safe limits must be maintained for these substances in the light of the latest generally recognised science."
It is said that packed food can only be as good as the packaging that holds it. Potential contamination that conflicts with the many advantages of plastics—such as good protection against germs and bacteria, or an airtight seal against the surroundings—can be countered through the correct choice of packaging.
Commenting on the packaging materials, Dr Nehring says: "No packaging that is intended to be used in contact with baby food and other foodstuffs may release materials into the food in quantities that could endanger the health of consumers. This rule applies, regardless of the material from which the packaging is made."
However, Dr Nehring points out that glass packaging with P/T closures is particularly suitable for pasteurised or sterilised baby food, since the food is protected from microbial spoilage and oxidation, and can be kept unrefrigerated for long periods without losing its valuable properties.
He explains: "Glass packaging is also noted for its particularly low substance migration to food and can be very effectively recycled, as can the metal closures. The packaging waste is therefore not harmful to the environment."
Dr Nehring also suggests to anyone who wishes to avoid PVC in baby food packaging can make use of packages that are fitted with a modern, metal closure using a PVC-free sealing compound. "This kind of closure does not include any softener in the sealing compound. As a consumer, we can often recognise these closures from a corresponding advertising print on the outside of the closure or on the label," he says.
Dr Nehring also points out that it is not usually possible to tell immediately whether food is packaged without PVC—there is no obligatory labelling system.
In some cases, metal-vacuum closures or P/T closures can be recognised after opening from a different colour of the sealing ring. It may, for example, be blue, but this is not obligatory.
"It is the job of the food company—the manufacturer of foods and packaging—as well as the legislative authorities, and of the supervisory authorities to create, and indeed to maintain suitable legal regulations, so that consumers are adequately protected from health hazards and from harmful effects from food caused by substance migration," says Dr Nehring.
Dr Nehring points out that Germany has a functioning system of consumer protection, on which every consumer can rely. "Of course, in this field as in every other, there are needs and possibilities for improvement on which everybody involved is constantly working," he says.
Voluntary identification could nevertheless be helpful in order to permit consumers a choice between PVC-based and PVC-free glass closures.
N.B. This article is an industry insight from Actega, the manufacturer of Provalin, a patented PVC-free sealing material for glass jars.