Removal of Listeria monocytogenes Biofilms from Stainless Steel by Use of Ultrasound and Ozone

2009 ◽  
Vol 72 (6) ◽  
pp. 1306-1309 ◽  
Author(s):  
ADAM R. BAUMANN ◽  
SCOTT E. MARTIN ◽  
HAO FENG
Keyword(s):  
Stainless Steel ◽  
Listeria Monocytogenes ◽  
Phosphate Buffer ◽  
Combined Treatment ◽  
Potassium Phosphate ◽  
Potassium Phosphate Buffer ◽  
Power Ultrasound ◽  
Biofilm Removal ◽  
Food Contact Surfaces ◽  
Contact Surfaces

The objective of this study was to determine the efficacy of power ultrasound and ozonation used individually, and in tandem, for the removal of Listeria monocytogenes biofilms from stainless steel chips. Stainless steel chips were inoculated with L. monocytogenes. Power ultrasound (20 kHz, 100% amplitude, 120 W) was applied for 30 or 60 s at a distance of 2.54 cm from a biofilm chip while it was submerged in 250 ml of sterile potassium phosphate buffer (pH 7.0). Ozone was cycled through the 250 ml of potassium phosphate buffer containing the biofilm chip also for 30 or 60 s at concentrations of 0.25, 0.5, or 1.0 ppm. Power ultrasound and ozonation were also used in tandem for testing of their combined effect. Each of the treatments alone resulted in a significant reduction in recoverable cells, with power ultrasound being the most effective (3.8-log CFU/ml reduction after 60 s). For the ozone in combination with power ultrasound treatment, reductions were significantly (P < 0.05) higher than by either treatment alone. There were no recoverable cells after 60 s of this combined treatment when an ozone concentration of 0.5 ppm was used (7.31-log CFU/ml reduction). These results indicated that the combination of power ultrasound and ozonation may be an effective treatment for biofilm removal from stainless steel food contact surfaces.

Comparison of Sampling Procedures for Recovery of Listeria monocytogenes from Stainless Steel Food Contact Surfaces

2012 ◽  
Vol 75 (6) ◽  
pp. 1077-1082 ◽  
Author(s):  
DIEGO GÓMEZ ◽  
AGUSTÍN ARIÑO ◽  
JUAN J. CARRAMIÑANA ◽  
CARMINA ROTA ◽  
JAVIER YANGÜELA
Keyword(s):  
Stainless Steel ◽  
Listeria Monocytogenes ◽  
Cost Effective ◽  
Sampling Procedure ◽  
Human Origin ◽  
Sampling Device ◽  
Food Contact ◽  
Food Contact Surfaces ◽  
Contact Surfaces ◽  
Sampling Procedures

A number of techniques exist for microbiological sampling of food processing environments in food industries. In the present study the efficacies of nine sampling procedures for the recovery of Listeria monocytogenes from food contact surfaces, including a new sampling device consisting of a miniroller, were evaluated and compared. A stainless steel table was inoculated with L. monocytogenes strain 935 (serovar 4b, human origin) and L. monocytogenes strain 437/07 (serovar 1/2b, food origin), at 105 CFU/100 cm2. L. monocytogenes strain 935 was best recovered with the minirollers (recovery of up to 6.27%), while poor recoveries (<0.30%) were obtained with the towel (one-ply composite tissue), alginate swab, metallic swab, and Petrifilm methods. In the case of L. monocytogenes strain 437/07 the replicate organism detection and counting (RODAC) ALOA contact plates yielded the best recoveries (4.15%), followed by the minirollers (up to 1.52%). Overall, recovery percentages with the minirollers were higher with stomacher homogenization than with Vibromatic agitation. The recovery percentages obtained for the Listeria strain of human origin were higher than those obtained with the food strain for all sampling procedures except Petrifilm and RODAC ALOA. With the miniroller device coated with wool fiber, the recovery of L. monocytogenes can be improved from 2 to 17 times over recoveries obtained with the sponge and cotton swab. This is the first report of a miniroller device for microbiological sampling in the available literature. The novel sampling procedure is convenient to apply on surfaces, is cost-effective, and results in better recovery of L. monocytogenes than do the conventional methods.

scholarly journals Evaluation of Quantitative Recovery Methods for Listeria monocytogenes Applied to Stainless Steel

2007 ◽  
Vol 90 (3) ◽  
pp. 810-816 ◽  
Author(s):  
David Kang ◽  
Joseph D Eifert ◽  
Robert C Williams ◽  
Steven Pao
Keyword(s):  
Stainless Steel ◽  
Listeria Monocytogenes ◽  
Pathogenic Bacteria ◽  
304 Stainless Steel ◽  
Contact Method ◽  
Cell Recovery ◽  
Food Contact ◽  
Food Contact Surfaces ◽  
Contact Surfaces ◽  
Quantitative Recovery

Abstract The ability of Listeria monocytogenes to attach to various food contact surfaces, such as stainless steel, polypropylene, and rubber compounds, is well documented. The retention of these or other pathogenic bacteria on food contact surfaces increases the risk of transmission to food products. The objective of this study was to compare several methods for quantitative recovery of Listeria monocytogenes from stainless steel surfaces. A cocktail of 4 serotypes of Listeria monocytogenes mixed in equivalent concentrations was inoculated onto type 304 stainless steel coupons in a 2 2 cm area. After 1 h exposure, coupons were sampled by one of the following methods: (1) swabbing with a premoistened Dacron swab; (2) rinsingwith phosphate-buffered saline; (3) direct contact onto tryptic soy agar containing 0.6% yeast extract (TSA + YE) plates for 10 s; (4) sonication in an ultrasonic water bath (40 kHz); (5) contact with the bristles of a sonicating brush head for 1 min; and (6) indirect contact (24 mm distance) with a sonicating brush head for 1 min. The 3 sonication methods yielded higher recovery than the other 3 methods (P < 0.05). Brushing the coupons with the sonicating brush head (contact or noncontact) yielded a recovery level of about 60%. The lowest cell recovery (about 20%) was observed with the swab and direct agar contact methods. After a 12 h exposure, recoveries ranged from 17.4 (brush contact method) to 2% (swab method).

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

2017 ◽  
Vol 81 (1) ◽  
pp. 59-67 ◽  
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.

Inactivation of Bacillus cereus Spores on Stainless Steel by Combined Superheated Steam and UV-C Irradiation Treatment

2019 ◽  
Vol 83 (1) ◽  
pp. 13-16 ◽  
Author(s):  
SANG-SOON KIM ◽  
SOO-HWAN KIM ◽  
SANG-HYUN PARK ◽  
DONG-HYUN KANG
Keyword(s):  
Stainless Steel ◽  
Bacillus Cereus ◽  
Superheated Steam ◽  
Dipicolinic Acid ◽  
Combined Treatment ◽  
Bactericidal Effect ◽  
Food Contact ◽  
Food Contact Surfaces ◽  
Contact Surfaces ◽  
Uv C

ABSTRACT Bacillus cereus spore contamination on food contact surfaces is of great concern in the food industry. Thus, in the present study, superheated steam (SHS) was used alone or combined with UV-C irradiation for inactivation of B. cereus spores inoculated on stainless steel coupons. Temperatures higher than 250°C were needed to effectively inactivate B. cereus spores by SHS treatment alone, while a synergistic bactericidal effect resulted from the sequential treatment of SHS before or after UV-C irradiation. The increased dipicolinic acid ratio obtained by the combined treatment had a significant role in the synergistic bactericidal effect. Therefore, the combined treatment of SHS and UV-C could be used effectively to inactivate B. cereus on stainless steel. It is recommended to use hurdle technology with reduced energy consumption to ensure microbiological safety on food contact surfaces. HIGHLIGHTS

scholarly journals Protecting ultra- and hyperhydrophilic implant surfaces in dry state from loss of wettability

2016 ◽  
Vol 2 (1) ◽  
pp. 557-560 ◽  
Author(s):  
Steffen Lüers ◽  
Markus Laub ◽  
Herbert P. Jennissen
Keyword(s):  
Dental Implants ◽  
Phosphate Buffer ◽  
Potassium Phosphate ◽  
Optimal System ◽  
Potassium Phosphate Buffer ◽  
Long Time ◽  
Optical Appearance

AbstractUltrahydrophilic titanium miniplates with sandblasted and acid etched (SLA) surfaces were protected from loss of hydrophilicity by an exsiccation layer of salt and stored in a dry state. Various salts in different concentrations were tested in respect to their conservation capacity and optical appearance. Potassium phosphate buffer in a specified composition appeared to be optimal. This optimal system was applied in a long time storage experiment showing no loss of hydrophilicity over years. It was also transferred with success to hyperhydrophilic dental implants.

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