A 2012 scientific opinion by European Food Safety Authority (EFSA) recommends changes to the EU’s own meat inspection procedures, criticizing its efforts for detecting and controlling Campylobacter and Salmonella in chicken meat. Regarding chemical intervention, the opinion further states that “chemical substances in poultry are unlikely to pose an immediate or acute health risk for consumers.”19This followed the release of 2011 guidelines issued by the international food safety organization Codex Alimentarius Commission (Codex) for the control of Campylobacter and Salmonella in chicken meat.20 These Codex guidelines cover, among other types of production controls, the use of certain hazard-based control measures, including acidified sodium chlorite and trisodium phosphate, among other antimicrobial rinses and oxidants.

In the view of the United States. the EC measures appear to be inconsistent with the EC's WTO obligations, including, but not limited to, the following:

    SPS Agreement Articles 2.2, 5, and 8, and Annex C(1);
   
    GATT 1994 Articles X:1 and XI:1;
   
    Agriculture Agreement Article 4.2; and
   
    TBT Agreement Article 2.

According to the United States, the EC measures also appear to nullify or impair the benefits accruing to the United States directly or indirectly under the cited agreements. (2009)
As far as I am aware the dispute is still ongoing.
The US is the second biggest exporter of chicken in the world, after Brazil. Up until 1997 the US chicken exports to EU were worth 300,000$
Perhaps there is a whiff of protectionism involved.