Performance of blow/fill/seal equipment under controlled airborne microbial challenges

Fundamental investigations have been carried out into the effectiveness of aseptic fill using Blow/Fill/Seal machinery. Techniques have been developed to generate and to maintain over prolonged periods, controlled microbial challenges of spores of Bacillus subtilis var. niger dispersed within the air of a containment room housing a Blow/Fill/Seal machine set-up to undertake medium fill studies. The range of spore concentrations that have been generated extends from as low as 3 x 10(2) to as high as 10(7) spores m-3. Responses to controlled microbial challenges have defined the relationship between product contamination and microbiological quality of the machine environment. The relationship is regular and amenable to extrapolation, so that it is now practicable to specify the microbiological quality of the machine environment, together with machine operating conditions, needed to attain a Sterility Assurance Level comparable to that targeted for terminal sterilization (i.e. 10(-6)). The impacts of mould configuration, air shower operation and location of point of fill on product contamination have also been examined.