Scientific Opinion on the re-evaluation of hexamethylene tetramine (E 239) as a food additive

Hexamethylene tetramine (HMT) is a food additive, currently only permitted in EU for use in Provolone cheese. The maximum permitted level is 25 mg/kg residual amount, expressed as formaldehyde, the break down product of HMT under acidic conditions. HMT has been previously evaluated by the Joint Expert Committee on Food Additives (JECFA, 1974) who established an ADI of 0.15 mg/kg bw/day based on a reproductive study with a NOEL of 15 mg/kg bw/day. Due to the limitations in the database the Panel could not identify a critical study and therefore to derive an ADI. However, the Panel noted that the exposure to formaldehyde from HMT of high level consumers of Provolone cheese equalled 18 µg formaldehyde/kg bw/day in adults and could be as high as 87 µg formaldehyde/kg bw/day in children according to a theoretical conservative assumption that all ripened cheese consumed was Provolone cheese. Considering the estimated exposure from the very limited permitted use, the toxicological database on HMT, the data from use of HMT therapeutically, the available oral toxicity and toxicokinetic data of formaldehyde and the magnitude of the potential effect on intracellular formaldehyde levels arising from this use of HMT, the Panel concluded that the use of HMT in Provolone cheese at the MPL of 25 mg/kg residual amount, expressed as formaldehyde, would not be of safety concern. However the Panel considered that any increase in the permitted uses of HMT or increases in the MPL of 25 mg /kg residual amount, expressed as formaldehyde would need detailed assessment which might require new toxicity data as well as use levels and/or an evaluation of its impact on formaldehyde levels in vivo

Proposed use of the plenary powers to suppress for all purposes the generic name Southernia Filipjev, 1927, with other rectifications of nomenclature (Glass Nematoda)

Volume: 17Start Page: 86End Page: 8

Le comportement diélectrique des solutions diluées de polyélectrolytes

Dielectric constants of aqueous solutions of polyacrylic acid, partially or totally neutralised by sodium hydroxide, and of sodium, lithium and baryum polymethacrylates, were measured at various frequencies, ranging from 10 to 500 kilocycles. Polymer concentration was varied from 0.1 to 10 millimoles of monomer per liter. The degree of polymerisation was varied from circa 300 to 3,500. All dispersion curves had an inflexion point for frequencies of approximately 100 kilocycles, so that the relaxation times were of the order of one microsecond. It was hardly influenced by the degree of neutralisation, by the polymer concentration or by the molecular weight. The dielectric increment, for a given frequency, increased with the degree of neutralisation, rising sharply until α reached 0.5, rather slowly for higher degrees of neutralisation. The dielectric increment was not proportional to the polymer concentration. It was considerably lower for the salt of a divalent cation, baryum, than for the lithium and sodium salts. The increment was slightly larger for the more mobile sodium than for the lithium polymethacrylate. The degree of polymerisation was practically without influence on the dielectric increment. All the observed facts point to an interpretation attributing the dielectric properties of dilute solutions of polyelectrolytes to relaxation phenomenon in the ionic atmospheres surrounding the charges localised along the polyion. Copyright © 1955 Wiley‐VCH Verlag GmbH & Co. KGaA, WeinheimSCOPUS: ar.jinfo:eu-repo/semantics/publishe