EFSA panel conditionally backs food preservation technique

By Joseph James Whitworth

- Last updated on GMT

Photo: Istock/Baloncici
Photo: Istock/Baloncici

Related tags Chlorine

A different method to generate gaseous chlorine dioxide (ClO2) can be used in cold food storage areas under certain conditions, according to a European Food Safety Authority (EFSA) panel.

The Food Additives and Nutrient Sources added to Food (ANS) panel made the decision in a scientific opinion regarding the safety of using it as preservative after a request from the European Commission.

Gaseous chlorine is generated from tubes that contain two reactants, which upon mixing slowly release gaseous chlorine dioxide. The tubes are used in cold storage rooms or in refrigerators for domestic use.

ANS said eating foods treated with gaseous ClO2​ under the proposed domestic refrigerator-like conditions would not be of safety concern but a new assessment would be needed if there was a change in conditions of use.

The panel noted that the mode of generation of ClO2​ proposed is different from those already used and accepted. Some information in the opinion is blocked​ due to potential confidentiality reasons.

Gaseous ClO2​ could be generated in tubes of different size and volume, depending on the volume of the cold area that is intended to be treated – i.e. a tube volume of 8mL for an 140-200 L intended volume/area of treatment.

Potential benefit

Released gaseous ClO2​ protects foodstuffs during storage against deterioration by microorganisms and against the growth of pathogenic microorganisms, said the applicant, Knick'n'clean.

This was determined by treating a refrigerator containing agar plates with Pseudomonas aeruginosa and Salmonella species, added the German firm.

ANS noted there was no information on whether gaseous ClO2​, under the conditions of use proposed, had any antimicrobial effect in foods.

An initial application was received in 2012 and Fraunhofer ITEM helped generate some data.

The panel noted that, for use as an antimicrobial agent, ClO2​ is added to water used in poultry processing; as a spray or dip for red meat, red meat parts and organs and ready-to-eat meats in an amount not exceeding a residual concentration of 3 ppm.

ClO2​ is authorised in the US for use in washing whole fresh fruits, vegetables, shelled beans and peas with intact cuticles at a concentration not exceeding 5 ppm (5 mg/kg).

The EFSA CONTAM panel established a TDI for chlorate of 3 μg/kg bw per day, based on the TDI established for perchlorate in 2015.

Upon request from the panel, the applicant generated data showing that, under the measured in-use conditions in a refrigerator, only a small amount of the total releasable ClO2​ from the tube was detected.

Exposure level

The maximum detected concentration of ClO2​ was 0.043 ppm, which corresponds to 15 μg/120 L. The mean concentration was 0.029 ppm, which corresponds to 10.2 μg/120 L.

Knick'n'clean also provided experimental data covering 28 days which showed that only <0.005% of the total amount of the gaseous reactant will be released during intended application duration.

The panel considered that the data indicated absence of potentially adverse chlorinated compounds in the model food matrices used by the applicant.

However, it noted the limitations of the model food matrices; in addition owing to the type of cold area used (a domestic refrigerator) in which a small size tube was used to generate the gaseous chlorine ClO2​, the consideration of absence of formation of potentially adverse compounds is restricted to these conditions and do not apply to larger areas where bigger tubes can be used.

ANS said it was aware the use of the material may lead to inhalation of ClO2​, but the possible risk resulting from exposure of the consumer was not assessed because it was outside the remit.

It recommended that the risk of inhalation of gaseous chlorine should be considered, particularly in the case of large cold storage areas. 

Ultraviolet (UV) spectroscopy was used for the determination of ClO2 ​and Infrared (IR) spectroscopy was used for detection of the possible gaseous reactant released and ClO2​ in activated and non-activated tubes. Ion chromatography was also used to detect chloride ions.

Related topics Food Safety & Quality

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