Formaldehyde-free preservative blends of 1,2-benzisothiazol-3(2H)-one (“BIT”) and certain dithiocarbamates inhibit microbial degradation of products that include ingredients which are naturally susceptible to, or have been previously exposed to, microbial contamination. This combination is effective in materials such as mineral slurries, pulp and paper slurries, wallboard joint compounds, mastics and asphalt emulsions. Also, methods for inhibiting the growth of microbes during storage of these materials without the use of formaldehyde or formaldehyde-releasing products.
