Potential of Escherichia coli O157:H7 to persist and form viable but non-culturable cells on a food-contact surface subjected to cycles of soiling and chemical treatment

Alfalfa seeds are sometimes subjected to a scarification treatment to enhance water uptake, which results in more rapid and uniform germination during sprout production. It has been hypothesized that this mechanical abrasion treatment diminishes the efficacy of chemical treatments used to kill or remove pathogenic bacteria from seeds. A study was done to compare the effectiveness of chlorine (20,000 ppm), H2O2 (8%), Ca(OH)2 (1%), Ca(OH)2 (1%) plus Tween 80 (1%), and Ca(OH)2 (1%) plus Span 20 (1%) treatments in killing Salmonella and Escherichia coli O157:H7 inoculated onto control, scarified, and polished alfalfa seeds obtained from two suppliers. The influence of the presence of organic material in the inoculum carrier on the efficacy of sanitizers was investigated. Overall, treatment with 1% Ca(OH)2 was the most effective in reducing populations of the pathogens. Reduction in populations of pathogens on seeds obtained from supplier 1 indicate that chemical treatments are less efficacious in eliminating the pathogens on scarified seeds compared to control seeds. However, the effectiveness of chemical treatment in removing Salmonella and E. coli O157:H7 from seeds obtained from supplier 2 was not markedly affected by scarification or polishing. The presence of organic material in the inoculum carrier did not have a marked influence on the efficacy of chemicals in reducing populations of test pathogens. Additional lots of control, scarified, and polished alfalfa seeds of additional varieties need to be tested before conclusions can be drawn concerning the impact of mechanical abrasion on the efficacy of chemical treatment in removing or killing Salmonella and E. coli O157:H7.

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Temperature Effects on Food Contact Surface Properties

Journal of Food Science ◽

10.1111/j.1365-2621.1990.tb01641.x ◽

1990 ◽

Vol 55 (4) ◽

pp. 1199-1200 ◽

Cited By ~ 6

Author(s):

JOSEPH McGUIRE ◽

ROBERT D. SPROULL

Keyword(s):

Surface Properties ◽

Contact Surface ◽

Temperature Effects ◽

Food Contact ◽

Food Contact Surface

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Inactivation of Escherichia coli O157:H7, Salmonella Enteritidis, and Listeria monocytogenes on Apples, Oranges, and Tomatoes by Lactic Acid with Hydrogen Peroxide

Journal of Food Protection ◽

10.4315/0362-028x-65.1.100 ◽

2002 ◽

Vol 65 (1) ◽

pp. 100-105 ◽

Cited By ~ 59

Author(s):

KUMAR S. VENKITANARAYANAN ◽

CHIA-MIN LIN ◽

HANNALORE BAILEY ◽

MICHAEL P. DOYLE

Keyword(s):

Escherichia Coli ◽

Hydrogen Peroxide ◽

Lactic Acid ◽

Listeria Monocytogenes ◽

Chemical Treatment ◽

Salmonella Enteritidis ◽

Deionized Water ◽

Wash Water ◽

Escherichia Coli O157 ◽

E Coli

The objective of this study was to develop a practical and effective method for inactivating or substantially reducing Escherichia coli O157:H7, Salmonella Enteritidis, and Listeria monocytogenes on apples, oranges, and tomatoes. Apples, oranges, and tomatoes were spot-inoculated with five-strain mixtures of E. coli O157:H7, Salmonella Enteritidis, and L. monocytogenes near the stem end and were submerged in sterile deionized water containing 1.5% lactic acid plus 1.5% hydrogen peroxide for 15 min at 40°C. Inoculated samples treated with sterile deionized water at the same temperature and for the same duration served as controls. The bacterial pathogens on fruits subjected to the chemical treatment were reduced by >5.0 log10 CFU per fruit, whereas washing in deionized water decreased the pathogens by only 1.5 to 2.0 log10 CFU per fruit. Furthermore, substantial populations of the pathogens survived in the control wash water, whereas no E. coli O157:H7, Salmonella Enteritidis, or L. monocytogenes cells were detected in the chemical treatment solution. The sensory and qualitative characteristics of apples treated with the chemical wash solution were not adversely affected by the treatment. It was found that the treatment developed in this study could effectively be used to kill E. coli O157:H7, Salmonella Enteritidis, and L. monocytogenes on apples, oranges, and tomatoes at the processing or packaging level.

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The Effect of Drop Volume on Contact Angle

Journal of Food Protection ◽

10.4315/0362-028x-54.3.232 ◽

1991 ◽

Vol 54 (3) ◽

pp. 232-235 ◽

Cited By ~ 7

Author(s):

JOSEPH MCGUIRE ◽

JIANGUO YANG

Keyword(s):

Contact Angle ◽

Surface Properties ◽

Solid Surface ◽

Contact Surface ◽

Contact Angles ◽

Equilibrium Contact Angle ◽

Drop Volume ◽

Food Contact ◽

Food Contact Surface ◽

Limiting Value

The effect of drop volume on the equilibrium contact angle, used in evaluation of food contact surface properties, was measured for liquids exhibiting both polar and nonpolar character on six different materials. Drop volumes used ranged from 2 to 40 μl. Contact angles were observed to increase with increasing drop volume in a range below some limiting value, identified as the critical drop volume (CDV). The CDV varied among materials and is explained with reference to surface energetic heterogeneities exhibited by each type of solid surface.

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Efficacy of Chemical Interventions against Escherichia coli O157:H7 and Multidrug-Resistant and Antibiotic-Susceptible Salmonella on Inoculated Beef Trimmings

Journal of Food Protection ◽

10.4315/0362-028x.jfp-12-195 ◽

2012 ◽

Vol 75 (11) ◽

pp. 1960-1967 ◽

Cited By ~ 12

Author(s):

IFIGENIA GEORNARAS ◽

HUA YANG ◽

GALATIOS MOSCHONAS ◽

MATTHEW C. NUNNELLY ◽

KEITH E. BELK ◽

...

Keyword(s):

Escherichia Coli ◽

Salmonella Typhimurium ◽

Chemical Treatment ◽

Sodium Metasilicate ◽

Multidrug Resistant ◽

Antimicrobial Treatment ◽

Sodium Chlorite ◽

Escherichia Coli O157 ◽

E Coli ◽

Salmonella Newport

Studies were conducted to compare the decontamination efficacy of six chemical treatments against Escherichia coli O157:H7 and multidrug-resistant and antibiotic-susceptible Salmonella inoculated on beef trimmings. The inocula, comprising four-strain mixtures of rifampin-resistant E. coli O157:H7 and antibiotic-susceptible or multidrug-resistant (MDR and/or MDR-AmpC) Salmonella Newport and Salmonella Typhimurium, were inoculated (3 log CFU/cm2) separately onto samples (10 by 5 by 1 cm) derived from beef chuck rolls. Samples were left untreated (control), were immersed for 30 s in acidified sodium chlorite (0.1%, pH 2.5), peroxyacetic acid (0.02%, pH 3.8), sodium metasilicate (4%, pH 12.6), Bromitize Plus (0.0225% active bromine, pH 6.6), or AFTEC 3000 (pH 1.2), or were immersed for 5 s in SYNTRx 3300 (pH 1.0). Levels of surviving Salmonella on treated trimmings were not influenced by serotype or antibiotic resistance phenotype and were generally similar (P > 0.05) or lower (P < 0.05) than levels of surviving E. coli O157:H7 regardless of antimicrobial treatment. Overall, depending on chemical treatment (reductions within each chemical treatment were similar among all tested inocula), initial counts of E. coli O157:H7 (2.7 to 3.1 log CFU/cm2) were reduced (P < 0.05) by 0.2 to 1.4 log CFU/cm2. Similarly, initial counts of the tested Salmonella inocula (2.8 to 3.3 log CFU/cm2) were reduced (P < 0.05) by 0.4 to 1.4 (Salmonella Newport, antibiotic susceptible), 0.3 to 1.4 (Salmonella Newport, MDRAmpC), 0.2 to 1.5 (Salmonella Typhimurium, antibiotic susceptible), 0.4 to 1.3 (Salmonella Typhimurium, MDR), and 0.4 to 1.5 (Salmonella Typhimurium, MDR-AmpC) log CFU/cm2, depending on antimicrobial treatment. Reductions obtained with sodium metasilicate were 1.3 to 1.5 log CFU/cm2, regardless of inoculum, and reductions obtained with the five remaining antimicrobial treatments were 0.2 to 0.7 log CFU/cm2 (depending on treatment). Findings of this study should be useful to regulatory authorities and the meat industry as they consider Salmonella contamination on beef trimmings.

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