We have over 80 years of experience in the development of safe processes for thermally processed canned foods. The increasing desire by the consumer for fresh-like, convenient foods has spurred research in the development of non-thermal, or 'cold pasteurization,' processes to minimize organoleptic changes but inactivate pathogens of concern. High pressure processing, ultraviolet radiation, pulsed electric fields, and chemical treatments (e.g. ozone, chlorine dioxide) have been shown to effectively reduce the most resistant micro-organism(s) of public health significance to a level that is not likely to present a public health risk under normal conditions of distribution and storage (pasteurization) (NACMCF, 2006). In general, these new technologies do not appear to result in unique microbiological hazards. For new technologies we will need to determine the most resistant pathogen of public health concern that is likely to be present in the product, determine the level of inactivation needed, and define the critical operating parameters to ensure the process is adequately delivered to the food.
In addition to new physical processing technologies, manufacturers are exploring novel food preservation systems, including the use of natural preservatives such as bacteriocins, competitive microflora, lysozyme, chitinases, lactoferrin, and lactoperoxidase, to name a few. By combining physical processes with these novel food processing systems, it may be possible to design processes for the precision destruction (or inhibition) of pathogenic and/or spoilage organisms, yet allow the desired fresh-like characteristics of the food to remain.
As with any new food processing technology, these emerging technologies will need to be evaluated to determine their impact with respect to eliminating competitors such that surviving or recontaminating pathogens become a concern; selecting for more resistant microorganisms such as pathogenic sporeformers; or sublethal injury resulting in pathogens that can repair themselves and cause foodborne illness (NACMCF, 2006). We must consider and conduct surveillance to determine whether a new technology may have unintended consequences on any surviving microorganism, such as potentiating adaptive responses and cross-protection against food-associated stresses, or impacting the expression of virulence genes.
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