TAIPEI (Taiwan News) — The Chiayi Public Health Bureau on Monday inspected 20 retail locations as part of ongoing efforts to track eggs tainted with the pesticide fipronil.

PX Mart’s head office reported receiving 20 boxes of eggs suspected of contamination, all of which had already been sold, according to health officials, per CNA.

A nationwide recall was issued days earlier for washed white-shell eggs bearing traceability code I47045 after testing detected 0.03 ppm of fipronil-sulfone, three times the permissible limit. PX Mart said its stores carried only one affected brand with the I47045 code and did not stock other recalled egg brands.

The Chiayi Public Health Bureau said PX Mart shops in the city voluntarily removed and returned 64 boxes of eggs suspected of being linked to the contaminated batch. Food safety notices were also posted in all affected outlets.

The Taiwan Food and Drug Administration said it continues to monitor drug residues in poultry, livestock, and aquatic products. It has tested 16 samples of eggs, duck eggs, and related products for veterinary and pesticide residues, all of which were found to comply with regulations.