Nitrosamine – A big no for printing inks for food and pharma packaging

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In 2019, FSSAI revised packaging regulations in India and mandated the use of BIS standard for printing inks called ‘IS 15495: Printing Ink For Food Packaging — Code Of Practice’ for manufacturing printing inks for food packaging. In addition to IS 15495, an Annexure A is linked, which is basically a negative list of such chemicals which are restricted to use in formulation of printing inks for food packaging. In section A-5, various compounds are listed including nitrosamines.

N-nitrosamines are such chemical substances which are known to exhibit carcinogenic properties. Generally, N-nitrosamines has not been intentionally added to the products. Human exposure to nitrosamines can result due to the formation of N nitroso compounds either during food preparation or storage.

In July 2018, the US Food and Drug Administration (USFDA) had alerted health care professionals and patients for a voluntary recall of several drug products containing the active ingredient valsartan which is an Angiotensin II Receptor Blocker (ARB) and belongs to a family of analogue compounds commonly referred to as the sartans. Valsartan was a world’s number one selling high blood pressure drug, used to treat high blood pressure and heart failure. This recall was due to an impurity, N-nitrosodimethylamine (NDMA), which was found in the recalled products. NDMA is classified as a probable human carcinogen (a substance that could cause cancer) based on results from laboratory tests. The presence of NDMA was unexpected and is thought to be related to changes in the way the active substance was manufactured.

According to several studies, N-nitrosodimethylamine (NDMA) is highly toxic in nature which induces tumors in a variety of human organs, including the liver, lungs, kidney, tongue, esophagus, lung, pancreas and bladder and have been classified as ‘probably carcinogenic to humans’ by the International Agency for Research on Cancer (IARC).

While review of impurities of valsartan increased, few other nitrosamines were subsequently detected in other medicines belonging to the sartan family, including: N-nitrosodiethylamine (NDEA), N -nitrosodiisopropylamine (NDIPA), N – nitrosoethylisopropylamine (NEIPA) and N -nitroso-N-methyl-4-aminobutyric acid (NMBA).

In several animal studies, it has been found that nitrosamines caused tumours and cancers in the studied animal. Therefore, most of the nitrosamines are considered carcinogenic in nature.

Nitrosamines are formed when nitrites, which can be formed from nitrates, react with a secondary or tertiary amine. According to the studies, evidences showed that nitrites or amines as unintentional contaminants present in raw materials such as starting materials, solvent, reagents or catalysts. These contaminants may react under some circumstances, within same or different processing steps, which consequently give rise to the formation of nitrosamines.

Packaging materials are also a potential source of nitrosamines in the finished products. Nitrocellulose-based printing inks are a potential source of nitrites in food and pharmaceutical packaging whereas, azo pigments are another source of aromatic amines, present in printing inks. However, amines are also naturally derived from food stuffs like meat products including cured meat, bacon, fish etc. Also, nitrates are used as a preservatives in foods.

NC based inks are mainly suitable for printing on substrates such as aluminum foil, blister foil, metallized and foil paper etc. Therefore, these inks are majorly used for printing of microwaveable food packages, and abundantly for pharmaceutical applications.

“Nitrocellulose is used as a polymer in the binding agent of solvent-based inks. Nitrites are formed due to the breakdown of nitrocellulose compounds at higher temperature, which have greater tendency to migrate through food packaging. These nitrite ions may react with the amines present in the foodstuff or printing inks itself to form carcinogenic nitrosamines. The concentration of nitrosamines tends to increase over time, and their formation is enhanced by high temperatures. The risk of nitrosamines formation in food is quite high when heating up ready-to-eat meals packed in microwaveable packages printed with NC based printing inks,” explains Neelakamal Mohapatra, VP – R&D, Innovation Department, Yansefu, India.

Hence, the selection of ink for the particular application plays a very crucial role in printing process. Therefore, the migration potential of packaging components and related health risks should be taken into account for the right choice of ink.

Recently, Yansefu designed a novel nitrocellulose (NC) free printing ink series named as ‘Sarjofoil PHM inks’ for food and particularly pharmaceutical applications. These inks have excellent printability on substrates like aluminum and blister foil and other superlative characteristics. Additionally, this ink series is designed in compliance with IS 15495 and various other food safety legislation.

“Yansefu strives for innovation considering product safety is the prime parameter. And our Sarjofoil PHM ink series is a magnificent example which manifest our determination to design innovative and compliance products,” says JK Sharma, CEO – Yansefu, India.