Microbial Safety of Pickled Fruits and Vegetables and Hurdle Technology

Escherichia coli O157:H7 is a member of the enterohemorrhagic group of pathogenic E. coli that has emerged as a foodborne pathogen of major public health concern. E. coli O157:H7 is highly tolerant of acidic pH and outbreaks attributed to this bacterium have been in many acidic foods which have pH level with similar to those of pickled products. Therefore, pickled vegetables, although acidic, may not safe. In pickling vegetables, the combination of preservation factors (heat, acetic acid, and salt) will contribute to increase the microbial safety. Recently, the concept of combining preservative factors for food preservation was developed, called ‘hurdle technology’. In hurdle technology, combination treatments are applied because it is expected that the use of combined preservative factors will have greater effectiveness at inactivating microorganisms than the use of any single factor. However, recent studies show that the combination of preservation factors can have unexpected antimicrobial activity. Therefore, this article includes an overall review of the microbial safety of fruits and vegetables, preservative method including major preservative factors used in pickling technology, concept and mechanism of hurdle technology and E. coli O157:H7.