Biofilms in the Food Environment

Joseph F. Frank

doi:10.1128/9781555815479.ch6

Chapter 6 : Biofilms in the Food Environment

Author: Joseph F. Frank¹

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Affiliations: 1: Department of Food Science and Technology, University of Georgia, Athens, GA 30602

Content Type: Monograph

Publication Year: 2009

Category: Food Microbiology; Applied and Industrial Microbiology

Book DOI: 10.1128/9781555815479

Chapter DOI: 10.1128/9781555815479.ch6

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Abstract:

Biofilms are structured microbial communities of cells differentiated to play specific roles in the maintenance of the community and its structure. In this chapter, the discussion of biofilm development is organized into three sections: initiation (reversible and irreversible attachment), structure development (maturation), and dispersal. Although there is a general process for how biofilms develop, mechanisms underlying the process differ among microorganisms. The chapter talks about the biofilm matrix, and biofilm ecosystem. Research on food processing biofilms has centered on the ability of pathogenic and spoilage microorganisms to grow or survive in these environments, with emphasis on the influence of sanitation procedures. Researchers isolated two types of rough colony variants of Listeria monocytogenes from biofilms, distinguished by short-chain and long-chain cell morphologies. Both types of rough variants exhibited enhanced biofilm formation, with the variants exhibiting increased cell chain length (filamentous growth) when grown as biofilms. The predominant microflora of water system biofilms can be characterized as having low physiological activity and as being difficult to culture using conventional plating methods. Biofilms containing mainly commensal microorganisms can form on roots, leaves, and the internal vascular tissues of edible plants. Cells in biofilms are more difficult to inactivate by application of antimicrobial chemicals and physical stresses than their planktonic counterparts. The major contributor of biofilm microorganisms in our diet is most likely fresh produce, since biofilms form on these foods before harvest, postharvest growth is likely, and the products are consumed without heat treatment.

Citation: Frank J. 2009. Biofilms in the Food Environment, p 95-115. In Jaykus L, Wang H, Schlesinger L (ed), Food-Borne Microbes. ASM Press, Washington, DC. doi: 10.1128/9781555815479.ch6

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Biofilms in the Food Environment

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Citation: Frank J. 2009. Biofilms in the Food Environment, p 95-115. In Jaykus L, Wang H, Schlesinger L (ed), Food-Borne Microbes. ASM Press, Washington, DC. doi: 10.1128/9781555815479.ch6

/content/10.1128/9781555815479.ch06.ch06fig01

FIGURE 1

Monospecies biofilms produced on polyvinyl chloride by unidentified isolates from a chicken house water system (stained with acridine orange). Incubation was in R2A broth for 7 days at 12°C. (Top) Dispersal of single cells and small micro-colonies between larger porous micro-colonies; (bottom) open space between porous microcolonies. (Micrographs by Nathanon Trachoo and J. F. Frank.)

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10.1128/9781555815479/f0098-01.gif

FIGURE 1

Citation: Frank J. 2009. Biofilms in the Food Environment, p 95-115. In Jaykus L, Wang H, Schlesinger L (ed), Food-Borne Microbes. ASM Press, Washington, DC. doi: 10.1128/9781555815479.ch6

/content/10.1128/9781555815479.ch06.ch06fig02

FIGURE 2

Micrographs illustrating the diversity of biofilms produced by five strains of Listeria monocytogenes grown on stainless steel at 32°C for 24 h in TSB. Reprinted from the Journal of Food Protection ( 31 ) with permission of the publisher.

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FIGURE 2

Citation: Frank J. 2009. Biofilms in the Food Environment, p 95-115. In Jaykus L, Wang H, Schlesinger L (ed), Food-Borne Microbes. ASM Press, Washington, DC. doi: 10.1128/9781555815479.ch6

/content/10.1128/9781555815479.ch06.ch06fig03

FIGURE 3

Biofilm formed in 1 day on a stainless steel coupon attached to the inner surface of the drip pan of a chiller unit. The unit was located on the ceiling of a room in a ready-to-eat meat processing plant. The coupon was stained with acridine orange and observed using the oil immersion objective (100×) and a 10× ocular lens on a Carl Zeiss Standard Microscope equipped for epifluorescence. Image courtesy of Amy C. Wong, Food Research Institute, University of Wisconsin, Madison.

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10.1128/9781555815479/f0109-01.gif

FIGURE 3

Citation: Frank J. 2009. Biofilms in the Food Environment, p 95-115. In Jaykus L, Wang H, Schlesinger L (ed), Food-Borne Microbes. ASM Press, Washington, DC. doi: 10.1128/9781555815479.ch6

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