Halal status of ethanol resulting from natural fermentation in food is controversial. According to the GSO standard (2538:2017), the maximum residue level (MRL) of ethanol in fruit juices is 0.1% (v/v). This study examined the effect of storage duration on the formation of ethanol and sugar content in fruit juices. A total of 49 different fruit juice samples (orange, apple, berry, pineapple, and a mixture of grapes and berries) were purchased from local supermarkets and analyzed for ethanol by

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... S-GC-FID and sugar content (glucose, fructose, and sucrose) by HPLC-RID. The samples were stored in the refrigerator (2-5℃) throughout the experiment and analyzed every week for one month during validity period. Results showed that all juices' ethanol levels were below the MRL 0.1% (v/v) and ranged from ˂ (LOQ: 0.02%) (orange, apple, and berry juices) up to 0.076% (v/v) (in mixed grape and berry juice), while total sugar content ranged from 6.5% (v/v) in orange juice up to 12.6% (v/v) in grape and berry mix juice. Ethanol levels and sugar content in all juices remained constant throughout the experiment, indicating that the fermentation process is inactive during storage and that of ethanol MRL in GSO standard is appropriate.