title: Behavior of Listeria monocytogenes in a multi-species biofilm with Enterococcus faecalis and Enterococcus faecium and control through sanitation procedures.
abstract: The formation of mono-species biofilm (Listeria monocytogenes) and multi-species biofilms (Enterococcus faecium, Enterococcus faecalis, and L. monocytogenes) was evaluated. In addition, the effectiveness of sanitation procedures for the control of the multi-species biofilm also was evaluated. The biofilms were grown on stainless steel coupons at various incubation temperatures (7, 25 and 39°C) and contact times (0, 1, 2, 4, 6 and 8 days). In all tests, at 7°C, the microbial counts were below 0.4 log CFU/cm(2) and not characteristic of biofilms. In mono-species biofilm, the counts of L. monocytogenes after 8 days of contact were 4.1 and 2.8 log CFU/cm(2) at 25 and 39°C, respectively. In the multi-species biofilms, Enterococcus spp. were present at counts of 8 log CFU/cm(2) at 25 and 39°C after 8 days of contact. However, the L. monocytogenes in multi-species biofilms was significantly affected by the presence of Enterococcus spp. and by temperature. At 25°C, the growth of L. monocytogenes biofilms was favored in multi-species cultures, with counts above 6 log CFU/cm(2) after 8 days of contact. In contrast, at 39°C, a negative effect was observed for L. monocytogenes biofilm growth in mixed cultures, with a significant reduction in counts over time and values below 0.4 log CFU/cm(2) starting at day 4. Anionic tensioactive cleaning complemented with another procedure (acid cleaning, disinfection or acid cleaning+disinfection) eliminated the multi-species biofilms under all conditions tested (counts of all micro-organisms<0.4 log CFU/cm(2)). Peracetic acid was the most effective disinfectant, eliminating the multi-species biofilms under all tested conditions (counts of the all microorganisms <0.4 log CFU/cm(2)). In contrast, biguanide was the least effective disinfectant, failing to eliminate biofilms under all the test conditions.
authors: University of Campinas (UNICAMP), Department of Food Technology, Brazil. Electronic address: megsfernandes@gmail.com.
authors: Meg
authors: M
authors: da Silva Fernandes
authors: University of Campinas (UNICAMP), Department of Food Science, Brazil. Electronic address: kabuki@fea.unicamp.br.
authors: Dirce Yorika
authors: DY
authors: Kabuki
authors: University of Campinas (UNICAMP), Department of Food Technology, Brazil. Electronic address: kuaye@fea.unicamp.br.
authors: Arnaldo Yoshiteru
authors: AY
authors: Kuaye
mesh_terms: D018441:Biofilms; D015169:Colony Count, Microbial; D004202:Disinfectants / Q000494:pharmacology; D013293:Enterococcus faecalis / Q000187:drug effects / Q000502:physiology*; D016984:Enterococcus faecium / Q000187:drug effects / Q000502:physiology*; D008089:Listeria monocytogenes / Q000187:drug effects / Q000502:physiology*; D010463:Peracetic Acid / Q000494:pharmacology; D012499:Sanitation / Q000379:methods* / Q000592:standards; D013193:Stainless Steel; D013696:Temperature; D013997:Time Factors
chemical_list: D004202:Disinfectants; D013193:Stainless Steel; D010463:Peracetic Acid
keywords: Biofilm; Cleaning; Disinfection; E. faecalis; E. faecium; L. monocytogenes