Exit day is 31st October
(a separate post will notify if/when this date changes, and it is unlikely a future exit day will be later than 31st January 2020)
The Food Safety Authority of Ireland (FSAI) has a Brexit section online (last reviewed 6th August 2019) that presents relevant information for persons who trade with the UK (this includes Northern Ireland) as part of a food business.
There is a huge amount of information on this online site.
A Q&A document consolidates much of it – here (dated 2 April 2019)
A key component is the Border Inspection Posts (BIPs). As the reader is aware, there is an International Land Border between Ireland and Northern Ireland (a part of the UK). This is known as the Irish Border.
The Irish Government is working with the EU to establish additional BIPs to serve trade across the Irish Border. The location of these additional BIPs is not yet announced, other than statements made by the Irish Government that they will be located away from the actual Irish Border physical position.
The BIPs at Dublin and Shannon (page 9 of the Q&A) are already set up.