99D-30 |
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H. LUO and H. Wang. Dept. of Food Science & Technology, Ohio State Univ., 2015 Fyffe Ct., 110 Parker Food Science Bldg., Columbus, OH 43210-1007 The presence of microbial biofilms in the processing environment is an important source for secondary contamination. Food-borne pathogens and spoilage microorganisms as biofilms are more resistant to sanitation and other adverse treatments. An important question is whether biofilm-forming ability is essential for strain persistent in the plant environment. The objective of the study is to investigate the possible involvement of a mixed culture ecosystem in promoting attaching and surviving of the so-called "non-biofilm-forming" organism in the environment. Our hypothesis is: certain bacterial strains might be "non-biofilm-former" by themselves, but can attach and survive in the environment and become part of the ecosystem involving other "primary" biofilm-forming strains. Several laboratory strains including Pseudomonas sp., Staphylococcus aureus and Bacillus subtilis were used in the study. The strains were inoculated either individually or mixed in 1 ml of TSB on both microtiter plates and the Lab-Tek Permanox Plastic Chamber Slides. The development of the attachment patterns over a time period by these strains was monitored by wide-field fluorescence microscopy (WFM). The P. sp. HL01 strain was found to be a strong biofilm former by itself. B. subtilis IG-20 strain didn't attach to surfaces as examined by WFM after 24 hrs of incubation. However, in the mixed culture situation, B. subtilis IG-20 was found attaching to the primary biofilm formed by P. sp. HL01 and the mixed culture ecosystem was evident. Mixed culture biofilms by Staphylococcus and Pseudomonas strains were also documented. The results suggested that although certain strains might not be able to attach to surface effectively by themselves and form biofilms, they could be part of a complex ecosystem involving primary biofilm forming strains. Minimizing contamination by primary biofilm-forming strains is critical for food safety.
Session 99D, Food Microbiology: General
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