21 CFR §1.379

1. (a)FDA may detain an article of food for a reasonable period that may not exceed 20 calendar days after the detention order is issued. However, an article may be detained for 10 additional calendar days if a greater period of time is required to institute a seizure or injunction action. The authorized FDA representative may approve the additional 10-calendar day detention period at the time the detention order is issued, or at any time within the 20-calendar day period by amending the detention order.
2. (b)The entire detention period may not exceed 30 calendar days.
3. (c)An authorized FDA representative may, in accordance with § 1.384, terminate a detention order before the expiration of the detention period.