The European Food Safety Authority (EFSA) opened its scientific investigation into ITX and related chemical 2-ethylhexyl-4-dimethylaminobenzoate (EHDAB) after traces of the ink products were found by Italy's regulators in Nestlé's baby milk products.
The ink curing agent was found to have migrated through the packaging and into the milk. The packaging was produced by Sweden-based Tetra Pak
The resulting controversy led to claims and counterclaims about the safety of the chemical by the Italian government, consumer groups, Nestlé and Tetra Pak. ITX is used in the curing of ink during the ultraviolet printing process.
Italy's food safety regulators detected ITX in some batches of the Nestlé's products in September. Tetra Pak stopped using ITX in the packing for the affected Nestlé products in October after being informed of the problem. The company is also phasing out the use of ITX in other fatty liquid products and for some juices.
ITX then hit the headlines three weeks ago after Italian authorities confiscated millions of litres of Nestlé baby milk and got a court order to force the company into recalling about two million litres of its Nidina and Latte Mio brands in Italy. Nestlé extended the recall to France, Spain and Portugal. Dutch group Numico was also involved in recalling some of its products.
Italy had originally informed the European Commission rapid alert system about the ITX problem in September. However, regulators were unhappy that there was still some product left on the shelves and under a court application got a Italian judge to demand the Nestlé recall.
In its original statement on ITX on 24 November, EFSA said: "On the basis of the very limited data available today, the presence of ITX in food could be considered undesirable but it is not likely to present a health risk at the levels reported."
The European Commission had asked the agency to make further scientific studies into ITX following a request by the Italian government.
ITX is not prohibited for use in food packaging by the EU, the EFSA said in its report. It is also not listed on the World Health Organisation's prohibited list.
In the milk products intended to be consumed in the first year of life, the level of ITX ranged from 120 to 305 micrograms per litre, EFSA foundl. The available data on two samples found ITX in milk for babies aged 12 months on were 74 and 445 microgram/l.
ITX was found at 600 microgram/l in a single sample of flavoured milk tested. No data on EHDAB levels were reported for the products.
In the milk and soy based products tested, not specifically intended for babies, the level of ITX ranged from 54 to 219 microgram/l and the level of EHDAB ranged from 27 to 134 microgram/l, for pack sizes of 1000 ml. In a chocolate milk sample (200 ml pack size) ITX was 295 microgram/l and EHDAB was 148 microgram/l.
In fruit juices, fruit nectars and drinks indicated as "cloudy" due to the presence of fruit pulp and fibres, the levels of ITX ranged from less than five microgram/l to 249 microgram/l. The levels of EHDAB ranged from less than five microgram/l to 125 microgram/l. The highest values were reported for smaller pack sizes.
In fruit juices, fruit nectars, water, and the drinks indicated as "clear", neither ITX nor EHDAB were detected.
"ITX was tested with contradictory results in limited genotoxicity studies in vitro," EFSA stated. "However clearly negative results were obtained in two adequate in vivo studies. In conclusion, the existing in vivo genotoxicity studies do not indicate a genotoxic potential for ITX. No other toxicity data on ITX are available."
In view of the lack of other toxicity data no further comment on the safety of ITX can be made, EFSA added.
The scientific evidence also indicated that EHDAB poses no safety concern, EFSA stated.
"However, materials and articles intended to come in contact with foods should comply with the general criteria laid down in Art.3 of Regulation (EC) No 1935/2004, i.e. should not transfer their constituents in food in quantities which could endanger human health or bring about unacceptable changes in composition or characteristics of foodstuffs," the report stated.
The issue over ITX highlights the uncertainty surrounding current legislation in the EU over the food industry's use of packaging chemicals, a problem that is meant to be fixed under a proposed directive on the registration, evaluation, authorisation and restriction of chemicals (Reach), approved by the bloc's parliament earlier this month.
Currently the EU relies on a negative list to regulate the use of chemicals. This means any chemical not on the European Food Safety Authority (EFSA) blacklist can normally be used for packaging food.
In a 24 November 2004 patent application in the US, Sun Chemical noted: "In recent years, thioxanthone derivatives, particularly isopropylthioxanthone (ITX) and diethylthioxanthone, have been extensively used in UV curable printing ink applications. However, these are not entirely satisfactory because, following curing, unreacted thioxanthone derivatives of this type have a tendency to migrate from printing inks into, for example, packaged foodstuffs."