3.2. Pathogen reduction testing
The compost was analyzed for fecal coliform and salmonella, which are used as pathogen contamination indicators (Sahlström et al., 2004, Gerba and Smith, 2005 and Sidhu and Toze, 2009). Fecal coliforms can survive in both aerobic and anaerobic conditions and is common in all initial compost piles. Most human pathogens occur from fecal matter and all fecal matter is loaded in fecal coliforms. Therefore, fecal coliforms are used as an indicator to determine if the chosen method for pathogen reduction (heat for compost) has met the requirements of sufficient temperature, time and mixing (Haug, 1993). If the fecal coliforms are reduced to below 1000 per gram dry wt. it is assumed all others pathogens are eliminated (Thompson et al., 2003). Potential problems are that fecal coliform can regrow during the curing phase or during shipping. This is because the conditions are now more favorable for growth than during the composting process. However, attention must be given to the area conditions in which the compost is stocked. Measured levels were well below regulatory thresholds, as shown in Table 2. These measurements confirmed that the temperatures achieved during the pilot program were sufficient to reduce pathogens.