Following a request from the European Commission, the Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) was asked to deliver a scientific opinion on the safety and efficacy of 32 compounds (aliphatic and aromatic mono- and di-thiols and mono-, di-, tri- and polysulphides with or without additional oxygenated functional groups belonging to chemical group 20) when used as flavourings for all animal species. All additives except dimethyl tetrasulphide are currently authorised for use as flavours in food and all have been detected in plant materials, fruits and processed foods; however, reports of their distribution vary greatly. During the assessment, the applicant withdrew the application for dimethyl tetrasulphide.
The FEEDAP Panel was unable to perform an assessment of six compounds (methanethiol, methyl propyl disulphide, dipropyl trisulphide, 3-mercaptobutan-2-one, 3-(methylthio)butanal and 3-methyl-1,2,4-trithiane) because of issues related to the purity of the compounds.
The FEEDAP Panel concludes that the following 25 compounds are safe for the target species at the proposed maximum dose level (0.05 mg/kg complete feed): 3-(methylthio)propionaldehyde, methyl 3-(methylthio)propionate, allylthiol, dimethyl sulphide, dibutyl sulphide, diallyl disulphide, diallyl trisulphide, dimethyl trisulphide, dipropyl disulphide, allyl isothiocyanate, dimethyl disulphide, 2-methylbenzene-1-thiol, S-methyl butanethioate, allyl methyl disulphide, 3-(methylthio)propan-1-ol, 3-(methylthio)hexan-1-ol, 1-propane-1-thiol, diallyl sulphide, 2,4-dithiapentane, 2-methyl-2-(methyldithio)propanal, 2-methylpropane-1-thiol, methylsulfinylmethane, propane-2-thiol, 3,5-dimethyl-1,2,4-trithiolane and 2-methyl-4-propyl-1,3-oxathiane.
No safety concern for the consumer would arise from the use of these 25 compounds belonging to CG 20 up to the highest safe level in feedingstuffs for all animal species, with the exception of allyl isothiocyanate. Although additional exposure to this substance through its low use level in animal feeds would not substantially increase consumer exposure, the FEEDAP Panel notes that the estimated exposure of consumers is already higher than the acceptable daily intake (ADI).
The FEEDAP Panel considers it prudent to treat all 25 compounds under assessment as irritant to skin, eyes and respiratory tract and as skin sensitisers.
The proposed concentration of 0.05 mg flavouring compound/kg feed is not expected to cause detrimental effects to the environment, except for 2-methylpropane-1-thiol, for which 0.04 mg/kg is expected to be safe.
Since all 25 compounds are used in food as flavourings, and their function in feed is essentially the same as that in food, no further demonstration of efficacy is necessary.