Dual-species biofilm of Listeria monocytogenes and Escherichia coli on stainless steel surface

The influence of inoculation level, material hydration, and stainless steel surface roughness on the transfer of Listeria monocytogenes from inoculated bologna to processing surfaces (stainless steel and polyethylene) was assessed. Slices of bologna (14 g) were inoculated with Listeria at different levels, from 105 to 109 CFU/cm2. Transfer experiments were done at a constant contact time (30 s) and pressure (45 kPa) with a universal testing machine. After transfer, cells that had been transferred to sterile stainless steel and polyethylene were removed and counted, and the efficiency of transfer (EOT) was calculated. As the inoculation level increased from 105 to 109 CFU/cm2, the absolute level of transfer increased in a similar fashion. By calculating EOTs, the data were normalized, and the initial inoculation level had no effect on the transfer (P > 0.05). The influence of hydration level on stainless steel, high-density polyethylene, and material type was investigated, and the EOTs ranged from 0.1 to 1 under all the conditions tested. Our results show that transfers to wetted processing surfaces (mean EOT = 0.43) were no different from dried processing surfaces (mean EOT = 0.35) (P > 0.05). Material type was shown to be a significant factor, with greater numbers of Listeria transferring from bologna to stainless steel (mean EOT = 0.49) than from bologna to polyethylene (mean EOT = 0.28) (P < 0.01). Stainless steel with three different surface roughness (Ra) values of <0.8 μm (target Ra = 0.25, 0.50, and 0.75 μm) and two different finishes (mechanically polished versus mechanically polished and further electropolished) was used to evaluate its effect on the transfer. The surface roughness and finish on the stainless steel did not have any effect on the transfer of Listeria (P > 0.05). Our results showed that when evaluating the transfer of Listeria, the use of EOTs rather than the absolute transfer values is essential to allow comparisons of transfer conditions or comparisons between research groups.

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Disinfectant action of Cymbopogon sp. essential oils in different phases of biofilm formation by Listeria monocytogenes on stainless steel surface

Food Control ◽

10.1016/j.foodcont.2009.08.003 ◽

2010 ◽

Vol 21 (4) ◽

pp. 549-553 ◽

Cited By ~ 69

Author(s):

Maíra Maciel Mattos de Oliveira ◽

Danilo Florisvaldo Brugnera ◽

Maria das Graças Cardoso ◽

Eduardo Alves ◽

Roberta Hilsdorf Piccoli

Keyword(s):

Stainless Steel ◽

Listeria Monocytogenes ◽

Essential Oils ◽

Biofilm Formation ◽

Steel Surface ◽

Stainless Steel Surface

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Reduction of Escherichia coli adhesion to AISI 316L stainless steel surface by using mechanical and electrochemical polishing processes

The Journal of Adhesion ◽

10.1080/00218464.2020.1785295 ◽

2020 ◽

pp. 1-16

Author(s):

Tuangthong Chotchutiphong ◽

Viboon Tangwarodomnukun

Keyword(s):

Escherichia Coli ◽

Stainless Steel ◽

Steel Surface ◽

316L Stainless Steel ◽

Stainless Steel Surface ◽

Aisi 316L ◽

Electrochemical Polishing ◽

Aisi 316L Stainless Steel

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Growth and Biofilm Formation by Listeria monocytogenes in Catfish Mucus Extract on Four Food Contact Surfaces at 22 and 10°C and Their Reduction by Commercial Disinfectants

Journal of Food Protection ◽

10.4315/0362-028x.jfp-17-103 ◽

2017 ◽

Vol 81 (1) ◽

pp. 59-67 ◽

Cited By ~ 8

Author(s):

Nitin Dhowlaghar ◽

Piumi De Abrew Abeysundara ◽

Ramakrishna Nannapaneni ◽

Mark W. Schilling ◽

Sam Chang ◽

...

Keyword(s):

Hydrogen Peroxide ◽

Stainless Steel ◽

Listeria Monocytogenes ◽

Quaternary Ammonium ◽

Biofilm Formation ◽

Steel Surface ◽

Stainless Steel Surface ◽

Food Contact Surfaces ◽

Contact Surfaces ◽

Ammonium Compounds

ABSTRACTThe objective of this study was to determine the effect of strain and temperature on growth and biofilm formation by Listeria monocytogenes in high and low concentrations of catfish mucus extract on various food contact surfaces at 10 and 22°C. The second objective of this study was to evaluate the efficacy of disinfectants at recommended concentrations and contact times for removing L. monocytogenes biofilm cells from a stainless steel surface covered with catfish mucus extract. Growth and biofilm formation of all L. monocytogenes strains increased with higher concentrations of catfish mucus extract at both 10 and 22°C. When 15 μg/mL catfish mucus extract was added to 3 log CFU/mL L. monocytogenes, the biofilm levels of L. monocytogenes on stainless steel reached 4 to 5 log CFU per coupon at 10°C and 5 to 6 log CFU per coupon at 22°C in 7 days. With 375 μg/mL catfish mucus extract, the biofilm levels of L. monocytogenes on stainless steel reached 5 to 6 log CFU per coupon at 10°C and 6 to 7.5 log CFU per coupon at 22°C in 7 days. No differences (P > 0.05) were observed between L. monocytogenes strains tested for biofilm formation in catfish mucus extract on the stainless steel surface. The biofilm formation by L. monocytogenes catfish isolate HCC23 was lower on Buna-N rubber than on stainless steel, polyethylene, and polyurethane surfaces in the presence of catfish mucus extract (P < 0.05). Contact angle analysis and atomic force microscopy confirmed that Buna-N rubber was highly hydrophobic, with lower surface energy and less roughness than the other three surfaces. The complete reduction of L. monocytogenes biofilm cells was achieved on the stainless steel coupons with a mixture of disinfectants, such as quaternary ammonium compounds with hydrogen peroxide or peracetic acid with hydrogen peroxide and octanoic acid at 25 or 50% of the recommended concentration, in 1 or 3 min compared with use of the quaternary ammonium compounds, chlorine, or acid disinfectants alone, which were ineffective for removing all the L. monocytogenes biofilm cells.

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Hygienic Shortcomings of Frozen Dessert Freezing Equipment and Fate of Listeria monocytogenes on Ice Cream–Soiled Stainless Steel

Journal of Food Protection ◽

10.4315/0362-028x.jfp-17-178 ◽

2017 ◽

Vol 80 (11) ◽

pp. 1897-1902

Author(s):

A. Inuwa ◽

A. Lunt ◽

C. Czuprynski ◽

G. Miller ◽

S. A. Rankin

Keyword(s):

Stainless Steel ◽

Listeria Monocytogenes ◽

Contact Time ◽

Pathogenic Bacteria ◽

Steel Surface ◽

Ice Cream ◽

Small Scale ◽

Stainless Steel Surface ◽

Frozen Dessert ◽

Complementary Study

ABSTRACT Although frozen dairy desserts have a strong record of safety, recent outbreaks of foodborne disease linked to ice creams have brought new attention to this industry. There is concern that small-scale frozen dessert equipment may not comply with or be reviewed against published comprehensive design and construction sanitation specifications (National Sanitation Foundation or 3-A sanitary standards). Equipment sanitary design issues may result in reduced efficacy of cleaning and sanitation, thus increasing the likelihood of postprocess contamination with pathogenic bacteria. In this context, and given that Listeria monocytogenes outbreaks are of great concern for the frozen dessert industry, a complementary study was conducted to evaluate the fate of L. monocytogenes in ice cream mix on a stainless steel surface. Our results showed that L. monocytogenes survived for up to 6 weeks at room temperature and 9 weeks at 4°C in contaminated ice cream on a stainless steel surface. Furthermore, chlorine- and acid-based surface sanitizers had no detrimental effect on the L. monocytogenes when used at a concentration and contact time (1 min) recommended by the manufacturer; significant reduction in CFU required 5 to 20 min of contact time.

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