Microbial Attachment and Limitations of Decontamination Methodologies

Authors: SOLOMON, ETHAN - DUPONT CHEM SOLUTION ENT; Sharma, Manan

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 4/1/2009
Publication Date: 6/1/2009
Citation: Solomon, E.B., Sharma, M. 2009. Microbial Attachment and Limitations of Decontamination Methodologies. In: Spers, G. M., Solomon, E. B., Matthews, K. R., editors. The Produce Contamination Problem: Causes and Solutions. New York, N.Y.: Academic Press. p. 21-45.

Interpretive Summary: Produce commodities are increasingly a source of foodborne disease in the United States. Bacterial foodborne pathogens like E. coli O157:H7 and Salmonella originate from animal hosts and progress through various environmental sources (water, soil, manure, animal feces, dust) to contaminate produce commodities. These pathogens can use a variety of strategies to survive on produce commodities, including attachment, formation of biofilms and aggregates on produce surfaces, and infiltration into subsurface tissues. Furthermore, bacterial pathogens attach preferentially to fresh-cut produce commodities, gaining a protective niche in a nutrient-rich environment on produce surfaces. Internalization of pathogens into fruits may be more likely to occur under certain temperature conditions (a positive temperature differential). However, uptake of bacterial cells through roots seems rare but more prevalent under sterile hydroponic growing conditions rather than in soil, and only when bacterial populations are extremely high. The virtual irreversible attachment of these pathogens to produce commodities, combined with their ability to form biofilms and aggregates, severely limits the chemical decontamination strategies that may be employed to remove or kill these cells. Several gaseous treatments (ozone, chlorine dioxide, cold plasma) may have potential as effective decontamination strategies. However, no decontamimation strategy will be as effective as an integrated food safety plan that includes growers, industry groups, and government agencies.

Technical Abstract: Produce commodities are increasingly a source of foodborne disease in the United States. Bacterial foodborne pathogens like E. coli O157:H7 and Salmonella originate from animal hosts and progress through various environmental sources (water, soil, manure, animal feces, dust) to contaminate produce commodities. These pathogens can use a variety of strategies to survive on produce commodities, including attachment, formation of biofilms and aggregates on produce surfaces, and infiltration into subsurface tissues. Furthermore, bacterial pathogens attach preferentially to fresh-cut produce commodities, gaining a protective niche in a nutrient-rich environment on produce surfaces. Internalization of pathogens into fruits may be more likely to occur under certain temperature conditions (a positive temperature differential). However, uptake of bacterial cells through roots seems rare but more prevalent under sterile hydroponic growing conditions rather than in soil, and only when bacterial populations are extremely high. The virtual irreversible attachment of these pathogens to produce commodities, combined with their ability to form biofilms and aggregates, severely limits the chemical decontamination strategies that may be employed to remove or kill these cells. Several gaseous treatments (ozone, chlorine dioxide, cold plasma) may have potential as effective decontamination strategies. However, no decontamimation strategy will be as effective as an integrated food safety plan that includes growers, industry groups, and government agencies.