Semicarbazide is a minor thermal decomposition product of azodicarbonamide used in the gaskets of certain food jars

Abstract

Evidence is presented for the first time showing that semicarbazide (SEM) is a minor thermal decomposition product of the blowing agent azodicarbonamide (ADC). A novel direct analytical method based on liquid chromatography electrospray ionization tandem mass spectrometry (LC-ESIMS/MS) has been developed to determine SEM in foamed polyvinyl chloride (PVC) seals of metal lids, as well as in commercially available ADC. The direct LC-MS/MS method for gaskets entails extraction of the gaskets in hot water, addition of ((15)N(2)(13)C)-SEM as internal standard, and injection of an aliquot directly into the LC-MS system, achieving good sensitivity (S/N = 348 for 2 ng injected on-column) and monitoring three characteristic mass transitions (m/z 76-->31; 76 -->44; 76-->59). Semicarbazide can be detected in thermally treated ADC, reaching up to 0.93 mmol mol(-1) at 220 degrees C, as determined by the direct LC-MS/MS method. This new method is also compared to the classical derivatization method using 2-nitrobenzaldehyde (2-NBA) that is routinely employed to determine SEM as an indicator of the usage of the antimicrobial drug nitrofurazone, the use of which is not authorized in the European Union (EU). Both methods revealed proportional results, with approx. 3-fold higher levels recorded by the direct SEM approach, probably due to differences in the extraction procedures used. A limited survey of plastic seals from used press twist and twist-off metal lids on food jars (non-foamed and foamed) revealed levels of SEM ranging from 2 to 8689 microg kg(-1)(average = 1593 microg kg(-1), n= 57 determinations).

Report of ESCO WG on non‐plastic Food Contact Materials

“…chromium, cadmium, lead), diisopropylnaphthalene, phthalates, chlorophenols, fluorescent whitening agents (Bononi and Tateo 2009;Domeño et al 2005;Skrzydlewska et al 2003;Zhang et al 2008;Diserens 2001;Aurela et al 1999). Extensive research on factors affecting migration using surrogate contaminants and the effect of different barrier layers have been performed (Castle 2004;Choi et al 2002;Johns et al 1996). Furthermore, several studies have focused on the kinetics of migration and modelling of potential contaminants in paper and board towards food and food simulants, as well as on the partition behaviour of volatile substances between cardboard and the gas phase (Triantafyllou et al 2005;Nerín and Asensio 2004;Castle 2004;Choi et al 2002;García-Gómez et al 2004;Haack and Franz 2000).…”

Scientific Opinion on nitrofurans and their metabolites in food

“…(1) as a migration or breakdown product from azodicarbonamide which has been used both as a blowing agent to foam the plastic sealing gaskets on metal lids of food jars and as a flour treatment agent in bread production (Becalski et al, 2004;Stadler et al, 2004); (2) as a reaction product formed between hypochlorite, used in cleaning, and carrageenan or powdered egg white (Hoenicke et al, 2004); and (3) as a naturally occurring compound from which SEM may be released in shrimps, prawns and crayfish and in honey (Saari and Peltonen, 2004;Van Poucke et al, 2011;McCracken et al, 2013;Crews, 2014 ), but it may continue to be used in other countries. Because no alternative marker residue for nitrofurazone has been identified to date, particular steps need to be taken when positive screening results for SEM are found (Sanders, 2003;Points et al, 2015).…”

“…SEM is a minor thermal decomposition product of azodicarbonamide (Stadler et al, 2004), which is a blowing agent used in sealing gaskets for metal lids on glass bottles and jars (EFSA, 2005). Owing to the migration of SEM from the gasket into the food, SEM occurrence has been reported in packaged food such as baby food.…”

“…In the case of SEM, there is a problem with its use as a marker metabolite for nitrofurazone in that SEM may occur as a residue in some foods from other sources (Becalski et al, 2004;Hoenicke et al, 2004;Saari and Peltonen, 2004;Stadler et al, 2004;Van Poucke et al, 2011;McCracken et al, 2013;Crews, 2014), potentially giving rise to false-positive results for illicit use of nitrofurazone. However, a suitable alternative marker metabolite for nitrofurazone has not been identified.…”

Age-related Susceptibility to Induction of Osteochondral and Vascular Lesions by Semicarbazide Hydrochloride in Rats

“…However, SEM has in fact been found in food in glass jars sealed with plastic gaskets manufactured using azodicarbonamide as a blowing agent, such as baby foods, fruit juices, jams, and conserves (European Food Safety Authority 2003; Stadler et al 2004). Other sources of contamination, such as from food processing by hypochlorite treatment, have further been suggested (Hoenicke et al 2004;Saari and Peltonen 2004).…”