Growth medium- and strain-dependent bactericidal efficacy of blue light against Shiga toxin-producing Escherichia coli on food-grade stainless steel and plastic

Biofilms are a mixture of bacteria and extracellular products secreted by bacterial cells and are of great concern to the food industry because they offer physical, mechanical, and biological protection to bacterial cells. This study was conducted to quantify biofilms formed by different Shiga toxin–producing Escherichia coli (STEC) strains on polystyrene and stainless steel surfaces and to determine the effectiveness of sanitizing treatments in control of these biofilms. STEC producing various amounts of cellulose (n = 6) or curli (n = 6) were allowed to develop biofilms on polystyrene and stainless steel surfaces at 28°C for 7 days. The biofilms were treated with 2% acetic or lactic acid and manufacturer-recommended concentrations of acidic or alkaline sanitizers, and residual biofilms were quantified. Treatments with the acidic and alkaline sanitizers were more effective than those with the organic acids for removing the biofilms. Compared with their counterparts, cells expressing a greater amount of cellulose or curli formed more biofilm mass and had greater residual mass after sanitizing treatments on polystyrene than on stainless steel. Research suggests that the organic acids and sanitizers used in the present study differed in their ability to control biofilms. Bacterial surface components and cell contact surfaces can influence both biofilm formation and the efficacy of sanitizing treatments. These results provide additional information on control of biofilms formed by STEC.

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In vitro inactivation effect of blue light emitting diode (LED) on Shiga-toxin-producing Escherichia coli (STEC)

Food Control ◽

10.1016/j.foodcont.2021.107990 ◽

2021 ◽

Vol 125 ◽

pp. 107990

Author(s):

Shuyan Wu ◽

Colleen Ross ◽

Joshua Hadi ◽

Gale Brightwell

Keyword(s):

Escherichia Coli ◽

Blue Light ◽

Shiga Toxin ◽

Light Emitting Diode ◽

Light Emitting ◽

Inactivation Effect

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Single- and Dual-Species Biofilm Formation by Shiga Toxin-Producing Escherichia coli and Salmonella, and Their Susceptibility to an Engineered Peptide WK2

Microorganisms ◽

10.3390/microorganisms9122510 ◽

2021 ◽

Vol 9 (12) ◽

pp. 2510

Author(s):

Zhi Ma ◽

Xia Tang ◽

Kim Stanford ◽

Xiaolong Chen ◽

Tim A. McAllister ◽

...

Keyword(s):

Escherichia Coli ◽

Stainless Steel ◽

Foodborne Pathogens ◽

Shiga Toxin ◽

Salmonella Enterica ◽

Biofilm Formation ◽

Single Species ◽

Protein Labeling ◽

Cross Contamination ◽

Temporal And Spatial

Shiga toxin-producing Escherichia coli (STEC) and Salmonella enterica are important foodborne pathogens capable of forming both single- and multi-species biofilms. In this study, the mono- and dual-species biofilms were formed by STEC O113:H21 and Salmonella enterica serovar Choleraesuis 10708 on stainless steel in the presence of beef juice over 5 d at 22 °C. The dual-species biofilm mass was substantially (p < 0.05) greater than that produced by STEC O113:H21 or S. Choleraesuis 10708 alone. However, numbers (CFU/mL) of S. Choleraesuis 10708 or STEC O113:H21 cells in the dual-species biofilm were (p < 0.05) lower than their respective counts in single-species biofilms. In multi-species biofilms, the sensitivity of S. Choleraesuis 10708 to the antimicrobial peptide WK2 was reduced, but it was increased for STEC O113:H21. Visualization of the temporal and spatial development of dual-species biofilms using florescent protein labeling confirmed that WK2 reduced cell numbers within biofilms. Collectively, our results highlight the potential risk of cross-contamination by multi-species biofilms to food safety and suggest that WK2 may be developed as a novel antimicrobial or sanitizer for the control of biofilms on stainless steel.

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Production of Vero Cytotoxin by Escherichia coli and Shiga Toxin by Shigella dysenteriae 1 as related to the growth medium and availability of iron

Zentralblatt für Bakteriologie ◽

10.1016/s0934-8840(89)80086-6 ◽

1989 ◽

Vol 272 (1) ◽

pp. 1-10 ◽

Cited By ~ 3

Author(s):

Henrik Chart ◽

Sylvia M. Scotland ◽

Bernard Rowe

Keyword(s):

Escherichia Coli ◽

Growth Medium ◽

Shiga Toxin ◽

Shigella Dysenteriae

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Biofilm Formation by Shiga Toxin-Producing Escherichia coli on Stainless Steel Coupons as Affected by Temperature and Incubation Time

Microorganisms ◽

10.3390/microorganisms7040095 ◽

2019 ◽

Vol 7 (4) ◽

pp. 95 ◽

Cited By ~ 9

Author(s):

Zhi Ma ◽

Emmanuel W. Bumunang ◽

Kim Stanford ◽

Xiaomei Bie ◽

Yan D. Niu ◽

...

Keyword(s):

Escherichia Coli ◽

Stainless Steel ◽

Shiga Toxin ◽

Incubation Time ◽

Food Processing ◽

Biofilm Formation ◽

Crystal Violet Staining ◽

Plate Counts ◽

Air Liquid Interface ◽

Over Time

Forming biofilm is a strategy utilized by Shiga toxin-producing Escherichia coli (STEC) to survive and persist in food processing environments. We investigated the biofilm-forming potential of STEC strains from 10 clinically important serogroups on stainless steel at 22 °C or 13 °C after 24, 48, and 72 h of incubation. Results from crystal violet staining, plate counts, and scanning electron microscopy (SEM) identified a single isolate from each of the O113, O145, O91, O157, and O121 serogroups that was capable of forming strong or moderate biofilms on stainless steel at 22 °C. However, the biofilm-forming strength of these five strains was reduced when incubation time progressed. Moreover, we found that these strains formed a dense pellicle at the air-liquid interface on stainless steel, which suggests that oxygen was conducive to biofilm formation. At 13 °C, biofilm formation by these strains decreased (P < 0.05), but gradually increased over time. Overall, STEC biofilm formation was most prominent at 22 °C up to 24 h. The findings in this study identify the environmental conditions that may promote STEC biofilm formation in food processing facilities and suggest that the ability of specific strains to form biofilms contributes to their persistence within these environments.

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Efficacy of detergent and quaternary ammonium sanitizer on shiga-toxin producing Escherichia coli (STEC) attached to stainless steel

Meat Science ◽

10.1016/j.meatsci.2014.09.115 ◽

2015 ◽

Vol 101 ◽

pp. 150

Author(s):

A.R. Parks ◽

M.M. Brashears

Keyword(s):

Escherichia Coli ◽

Stainless Steel ◽

Shiga Toxin ◽

Quaternary Ammonium

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Activity of Bacteriophage and Complex Tannins against Biofilm-Forming Shiga Toxin-Producing Escherichia coli from Canada and South Africa

Antibiotics ◽

10.3390/antibiotics9050257 ◽

2020 ◽

Vol 9 (5) ◽

pp. 257

Author(s):

Emmanuel W. Bumunang ◽

Collins N. Ateba ◽

Kim Stanford ◽

Yan D. Niu ◽

Y. Wang ◽

...

Keyword(s):

Escherichia Coli ◽

South Africa ◽

Stainless Steel ◽

Foodborne Pathogens ◽

Shiga Toxin ◽

Biofilm Formation ◽

Condensed Tannin ◽

Plant Secondary Metabolites ◽

Brown Seaweed ◽

E Coli

Bacteriophages, natural killers of bacteria, and plant secondary metabolites, such as condensed tannins, are potential agents for the control of foodborne pathogens. The first objective of this study evaluated the efficacy of a bacteriophage SA21RB in reducing pre-formed biofilms on stainless-steel produced by two Shiga toxin-producing Escherichia coli (STEC) strains, one from South Africa and the other from Canada. The second objective examined the anti-bacterial and anti-biofilm activity of condensed tannin (CT) from purple prairie clover and phlorotannins (PT) from brown seaweed against these strains. For 24-h-old biofilms, (O113:H21; 6.2 log10 colony-forming units per square centimeter (CFU/cm2) and O154:H10; 5.4 log10 CFU/cm2), 3 h of exposure to phage (1013 plaque-forming units per milliliter (PFU/mL)) reduced (p ≤ 0.05) the number of viable cells attached to stainless-steel coupons by 2.5 and 2.1 log10 CFU/cm2 for O113:H21 and O154:H10, respectively. However, as biofilms matured, the ability of phage to control biofilm formation declined. In biofilms formed for 72 h (O113:H21; 5.4 log10 CFU/cm2 and O154:H10; 7 log10 CFU/cm2), reductions after the same duration of phage treatment were only 0.9 and 1.3 log10 CFU/cm2 for O113:H21 and O154:H10, respectively. Initial screening of CT and PT for anti-bacterial activity by a microplate assay indicated that both STEC strains were less sensitive (p ≤ 0.05) to CT than PT over a concentration range of 25–400 µg/mL. Based on the lower activity of CT (25–400 µg/mL), they were not further examined. Accordingly, PT (50 µg/mL) inhibited (p ≤ 0.05) biofilm formation for up to 24 h of incubation at 22 °C, but this inhibition progressively declined over 72 h for both O154:H10 and O113:H21. Scanning electron microscopy revealed that both SA21RB and PT eliminated 24 h biofilms, but that both strains were able to adhere and form biofilms on stainless-steel coupons at longer incubation times. These findings revealed that phage SA21RB is more effective at disrupting 24 than 72 h biofilms and that PT were able to inhibit biofilm formation of both E. coli O154:H10 and O113:H21 for up to 24 h.

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Biofilm Formation by Shiga Toxin–Producing Escherichia coli O157:H7 and Non-O157 Strains and Their Tolerance to Sanitizers Commonly Used in the Food Processing Environment†

Journal of Food Protection ◽

10.4315/0362-028x.jfp-11-427 ◽

2012 ◽

Vol 75 (8) ◽

pp. 1418-1428 ◽

Cited By ~ 65

Author(s):

RONG WANG ◽

JAMES L. BONO ◽

NORASAK KALCHAYANAND ◽

STEVEN SHACKELFORD ◽

DAYNA M. HARHAY

Keyword(s):

Escherichia Coli ◽

Shiga Toxin ◽

Biofilm Formation ◽

Bacterial Colonization ◽

Critical Role ◽

Pellicle Formation ◽

Food Contact ◽

Food Contact Surfaces ◽

Contact Surfaces ◽

Strain Dependent

Shiga toxin–producing Escherichia coli (STEC) strains are important foodborne pathogens. Among these, E. coli O157:H7 is the most frequently isolated STEC serotype responsible for foodborne diseases. However, the non-O157 serotypes have been associated with serious outbreaks and sporadic diseases as well. It has been shown that various STEC serotypes are capable of forming biofilms on different food or food contact surfaces that, when detached, may lead to cross-contamination. Bacterial cells at biofilm stage also are more tolerant to sanitizers compared with their planktonic counterparts, which makes STEC biofilms a serious food safety concern. In the present study, we evaluated the potency of biofilm formation by a variety of STEC strains from serotypes O157:H7, O26:H11, and O111:H8; we also compared biofilm tolerance with two types of common sanitizers, a quaternary ammonium chloride–based sanitizer and chlorine. Our results demonstrated that biofilm formation by various STEC serotypes on a polystyrene surface was highly strain-dependent, whereas the two non-O157 serotypes showed a higher potency of pellicle formation at air-liquid interfaces on a glass surface compared with serotype O157:H7. Significant reductions of viable biofilm cells were achieved with sanitizer treatments. STEC biofilm tolerance to sanitization was strain-dependent regardless of the serotypes. Curli expression appeared to play a critical role in STEC biofilm formation and tolerance to sanitizers. Our data indicated that multiple factors, including bacterial serotype and strain, surface materials, and other environmental conditions, could significantly affect STEC biofilm formation. The high potential for biofilm formation by various STEC serotypes, especially the strong potency of pellicle formation by the curli-positive non-O157 strains with high sanitization tolerance, might contribute to bacterial colonization on food contact surfaces, which may result in downstream product contamination.

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