Food borne bacteria isolated from spices and fate of Cronobacter sakazakii ATCC 29544 in black pepper exposed to drying and various temperature conditions

Abstract

Food-borne disease outbreaks caused by spices have been on the increase in the recent years, although they are rarely reported in the developing countries. The purpose of this work therefore, is to show that spices sold in selected retail outlets in Durban South Africa may contain unacceptable level of pathogenic microorganisms including Cronobacter sakazakii which may survive desiccation and high temperature. Selected spices were purchased from four retail outlets in Durban and examined for the presence of aerobic bacteria (AB), aerobic sporeformers (ASF), anaerobic sporeformers (AnSF),Staphylococcus aureus and C. sakazakii using ISO methods. Black pepper was inoculated with 108 cfu/ml of C. sakazakii ATCC 29544 and subjected to pasteurization temperature, desiccation temperature and they were later stored in refrigeration and room temperatures for 72 h. The mean values of AB, ASF, AnSF and S. aureus in the sampled spices were 2.98, 3.05, 1.82 and 1.67 log cfu/g, respectively; however analysis of variance showed that S. aureus was significantly low in cinnamon as compared to other spices. C. sakazakii was recovered in 50% of the samples tested. The result of the impact of processing temperature on black pepper inoculated with C. sakazakii ATCC 29544 showed that pasteurization at 72°C for 15 s was unable to eradicate all the pathogens. Desiccation (58°C for 50 min) combined with low temperature storage however was able to eliminate the pathogen. The sampled spices constitute a public health risk and C. sakazakii ATCC 29544 was able to survive high temperature such as pasteurization. Also, spices contaminated with CS may still grow after desiccation if stored at room temperature. Key words: Bacteria, pathogens, Cronobacter sakazaki, temperature, desiccation.