Assessment of the Microbiological Quality of Spices and Herbs
This investigation of the mirobiology of spices and herbs has resulted in the isolaton of pathogenic, potentially pathogenic and spoilage organisms. Tests undertaken included Standard Plate Count (SPC), Yeast and Mold Count, counts for Escherichia coli, coliforms, Bacillus cereus, presumptive Clostridium perfringens; and the presence of Salmonella. The SPC ranged from less than 1.0 × 102 cfu/g in cloves and cayenne pepper to 2.0 × 108 cfu/g in black peppercorns. Most other spices and herbs averaged a total microbial load of about 1.0 × 105 cfu/g. Cloves and cayenne were the only spices found to be free of B. cereus, C. perfringens, coliforms, E. coli, and Salmonella spp.; and low in mold count. In contrast, peppercorns consistently had the highest level of microbial contamination, containing high levels of all organisms tested. Sporeformers and coliforms were detected in most other spices and herbs; B. cereus at a load ranging from less than 1.0 × 102 cfu/g to 1.0 × 105 cfu/g, with most being less than 1.0 × 103 cfu/g (except for cinnamon and broken mace which yielded higher counts); presumptive C. perfringens counts were usually <1.0 × 102 cfu/g (except for mixed herbs and ground paprika); and coliforms at <10/g (except for ground paprika which yielded higher counts). Salmonella was isolated from black peppercorns, white peppercorns and fenugreek seed at a relatively high incidence level (8.2, 1.5, 7.1%, respectively). Fumigation with ethylene oxide proved effective; resulting in Salmonella-free spices and substantial reduction (>90%) in the overall organism count. The spice toxicity tests in regard to Salmonella demonstrated that diluted spice:pre-enrichment ratios of 1:1000 are necessary for cloves, pimento, cinnamon, oregano and mustard seed to confidently isolate this organism of public health concern.