ABSTRACT
Outbreaks and recalls related to microbiological contamination are a rare occurrence in the realm of aseptically processed and packaged foods and beverages. Nevertheless, occasional or sporadic spoilage incidents, discovered before product enters distribution channels, do occur with some frequency. The products susceptibility (i.e., nutrient-rich, low-acid, shelf-stable products), the complexity of aseptic lines, and long production runs make diagnosing spoilage problems extremely difficult. Hence, prevention of contamination through proper design, execution, and proper line maintenance is essential in the successful production of aseptic products. This chapter aims to provide an overview of the type of microorganisms most commonly associated with contamination of these types of products. Considerations in the design of the thermal process as a function of food safety and sterilant tolerance of pertinent microorganisms are discussed in detail. Decimal reduction times (D-values) and z-values are presented for pathogenic and spoilage organisms of importance in this category. Finally, some of the most common causes of microbiological contamination in aseptically processed products are identified and preventive measures are offered to avoid spoilage problems before they occur.
The contents of this chapter focus on low-acid, shelf-stable, aseptically packaged foods, but it also touches on other products using similar technologies, such as refrigerated, extended shelf-life products, and high-acid, acidified shelf-stable products. For the purpose of this chapter, aseptic process technology includes all processes that rely on continuous heating followed by delivering a predetermined process lethality in a hold tube, continuous cooling, and filling the processed products in an aseptic or hygienic filler.
