The present study is the first in a series designed to determine whether or not acute or chronic exposure to ammoniated atmospheres compromises olfactory perception in the pig. Herein, we focused on acute effects of ammonia on food location. As a prerequisite, the relative consumption of a range of 15 odourized visible foods by eight Duroc×Landrace pigs ( Sus scrofa) was examined over 15 days in Experiment 1. This enabled us to identify the most and least preferred types for later use in olfactory perception tasks in Experiments 2 and 3. Five of these odourized foods are categorised by humans as sweet (almond oil, peach, raspberry, strawberry and vanilla), six as bitter (anise oil, benzaldehyde, caffeine, cetyl pyridium chloride, eugenol and sucrose octaacetate) and three as sour (acetic acid, butyric acid and propionic acid). A control food treated with de-ionized water was also included. A 250-g sample of each of eight food types was presented in eight food bowls (one sample per food bowl) positioned along the sides of a square pen. Water was available ad libitum. Pigs were tested individually for 30 min. An analysis of variance (ANOVA) showed that the pigs consumed significantly less food when it was treated with eugenol, anise oil or benzaldehyde rather than any of the other odourants ( P<0.001). A hierarchical cluster analysis of actual food consumption grouped these `bitter' foods into two separate categories and grouped all `sour' foods together. The other foods were placed into two other clusters, though consumption of the unodourized control, the `sweet' and the remaining `bitter' foods did not differ significantly from that of `sour' odourized foods ( P>0.05). The cluster analysis also showed individual differences in the preferences of the pigs for some of the most and least preferred foods. Experiments 2 and 3 addressed the question of whether acute, simultaneous exposure to 40 ppm ammonia would compromise the pigs' ability to locate buried, odourized wafer paper food parcels. Food parcels were treated with either almond oil or benzaldehyde, which had been identified in Experiment 1 as among the most and the least preferred odourants, respectively. A control parcel filled with wheat straw was also presented. All parcels were buried under wheat straw in an octagonal exposure chamber. In Experiment 2, three parcels of the same type were buried in six compartments of the chamber. The pigs were given 3 min in each compartment to find these parcels. In Experiment 3, one parcel of each type (i.e., almond oil, benzaldehyde and control) was buried in each of the eight compartments and, this time, the pigs were given only 1 min in each compartment to find the parcels. In both experiments, half of the compartments were filled with fresh air while the other half were polluted with approximately 40 ppm of ammonia. Whereas the pigs rapidly found most of the odourized parcels, they uncovered very few of the controls ( P<0.001). Unlike the results of Experiment 1, the pigs no longer expressed a preference for either odourized food ( P>0.05). Testing in an ammoniated atmosphere did not affect the number of parcels of each type found or the latency to find them ( P>0.05). Thus acute simultaneous ammonia exposure had no hyposmic or hyperosmic effect on the detection of buried odourized food.