The focus of this short symposium is on metabiotic effects and food safety significance of spoilage microorganisms that can increase the pH of acid and acidified food products, resulting in more favorable growth environments for pathogenic microorganisms.  Acid-resistant pathogens can survive and cause disease in acidified foods, such as apple cider, orange juice, and some pickled vegetable products that have pH values below 4.0.  Recent FDA guidance has raised concerns about spoilage molds (such as Penicillium spp., Aspergillus spp., Alternaria spp., Cladosporium spp., Fusarium spp.) and bacteria (such as Bacillus licheniformis) that can increase the pH of acidified foods and beverages, potentially resulting in a metabiotic effect that allows spore germination, growth, and toxin production by Clostridium botulinum.  Several studies in home-canned tomatoes and tomato juice have supported this hypothesis.  Certain metabiotic associations between foodborne molds and pathogenic bacteria have been observed in fresh produce, as well as in mold-ripened cheeses.  Molds have been reported to enhance the growth and survival of pathogens by changing their growth environments.  These concerns are addressed by both FDA guidelines and the Food Safety Modernization Act.  Given the proliferation of novel fermented and acidified products and imported foods, there is a pressing need for better understanding of processing conditions that will assure safety and support regulatory compliance.

Presentations