The use of non-sterile casein in building materials, especially in self-levelling floor-topping compound (putty), led to various defects in buildings with these materials. Bubbles in the mattings, dark patches unevenly spread over the floor and a very unpleasant odour developed. The defects were commonly induced or accelerated if the humidity in the floor was high. Our earlier studies have concluded that the cause of these problems is due to the growth of alkalitolerantClostridia. The presence of volatile mono-amines in air samples taken in the buildings also confirms our early theories. Due to the high pH of the putty, amines formed in the topping compound will easily be emitted into the air. Some of the amines are commonly found in spent growth media ofClostridia as well as in head-space samples from bacterial suspensions. By the use of gas chromatography (GC) we have been able to detect triethylamine, pyrrolidine, di-iso-butylamine, 2-ethyl-hexylamine and n-octylamine in the air samples. Air sampling was carried out by impinging in weak acidic solutions and adsorption on silica gel.

Along with the mono-amines, ammonia has also been detected. The sampling was carried out using Draeger Tubes, which also non-specifically indicate several volatile amines in addition to ammonia. The amount of amines recovered was well below official threshold limits. The amount was in the parts per billion (ppb) region, whereas official threshold limits are usually in the 1–25 parts per million (ppm) region.