The bacterial contamination of porcine oesophagi immediately after collection (100 samples) and of frozen just before preparation (40 samples) was assessed. The fresh oesophagi were found to show a rather high degree of contamination: aerobic count approximately 10(6)-10(7) and Enterobacteriaceae approximately 10(3)-10(4)/g. The frozen oesophagi showed even higher counts: total aerobic counts approximately 10(7)-10(8) and Enterobacteriaceae approximately 10(4)-10(5)/g. Hygiene during the collection of porcine oesophagi was visually assessed in six abbratoirs and found to be satisfactory in two, mediocre in three and poor in one. The effects of processing the oesophagus by cleaning and removing the mucous membrane on bacterial counts, pH, colour and odour were assessed before and during storage at 4 degrees C. and 20 degrees C. Both cleaning and removal of the mucous membrane caused up to a tenfold reduction of bacterial counts. After seven days' storage at 4 degrees C., the bacterial counts of the processed oesophagi were significantly lower than those of the non-processed oesophagi (p less than 0.01). The processed oesophagi stored at 4 degrees C. were four days' storage.