scholarly journals Influence of suspension liquid total solids on E. coli O157:H7 survival and transfer efficacy between green tomatoes and cardboard

10.5219/1210 ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 941-949
Author(s):  
Oleksandr Tokarskyy ◽  
Mykhaylo Korda
Keyword(s):  
Transfer Rate ◽  
Positive Transfer ◽  
Post Inoculation ◽  
Cross Contamination ◽  
Organic Residues ◽  
Hydrophobic Properties ◽  
Transfer Rates ◽  
E Coli ◽  
Hygroscopic Nature ◽  
Peptone Water

 The objectives of this study were: a) to determine E. coli O157:H7 survival on tomatoes and cardboard squares post-drying, stored at 25 ºC in humidified environment for four days, in buffered peptone water (BPW), and 0.1% diluted peptone (DP); b) to determine pathogen transfer rates (0, 1.5, or 24-hours drying post-inoculation), from inoculated tomato surfaces to uninoculated cardboard squares and conversely; and c) to evaluate SystemSure Plus ATP luminometer for recognizing contamination on visibly soiled (BPW) or visible clean (DP) cardboard. In tomato inoculation studies, E. coli O157:H7 survived better on the fruit when the inoculum was prepared using DP as compared to BPW. The 1.5-hours post drying counts of 5.34 and 5.76 log10 CFU.mL-1 in the rinsate substantially declined to 1.45 and 1.17 log10 CFU.mL-1 on day four, for DP and BPW, respectively. In cardboard inoculation studies, E. coli O157:H7 persisted for four days, with 1.5-hours post-drying counts and day four counts of 4.53 (DP) and 2.55 log10 CFU.mL-1 (BPW), contrary to 3.81 (DP) and 1.92 log10 CFU.mL-1 (BPW). Under the first impression, the slower die-off of E. coli O157:H7 on cardboard questions the possibility of reusing cardboard boxes due to the potential for cross-contamination. In wet transfer (0 hour drying) trials, both tomato-to-cardboard and cardboard-to-tomato yielded 100% positive transfers irrespective of diluent type. Dry transfer (1.5-hours drying interval post inoculation) from tomato-to-cardboard were 100% positive, but no positives were noted when inoculated, dried cardboard was contacted to tomatoes, irrespective of diluent. Results of transfers with BPW as the diluent showed 100% positive transfer from 24-hours dry tomatoes-to-cardboard, as inoculation spots on the tomatoes remained moist due to hygroscopic nature of solutes in BPW. Conversely, only a 40% positive transfer rate was observed under the same conditions with DP as diluent. No positive transfers were recorded from 24-hours dry cardboard-to-tomatoes, irrespective of diluent type. Though E. coli O157:H7 survived better on the surface of cardboard compared to the surface of tomatoes on day four, the dry transfers were more efficient from tomatoes-to-cardboard than conversely, possibly due to smooth and hydrophobic properties of the tomato, and rough and porous surface of the cardboard. ATP luciferase UltrasnapTM swab test showed 9/9 “pass” results for sterile liquid DP and BPW, while 9/9 “fail” results were observed with liquid peptone and BPW contaminated at ca. 9.0 log10 CFU.mL-1 E. coli O157:H7. Cardboard squares treated and dried, with sterile DP, showed 8/9 “pass” ATP luciferase results, and 1/9 “warning”, while cardboard squares with contaminated DP showed 9/9 “fail” result. Cardboard squares treated and dried, with sterile BPW, showed 7/9 “pass” ATP luciferase results, and 2/9 “warning”, while cardboard squares with contaminated BPW showed 9/9 “fail” result. Luminometer can simplify detection of microbial load, as well as organic residues, helping to check cardboard boxes for cleanness.

scholarly journals Transfer efficacy of Escherichia coli O157:H7 between surfaces of green mature tomatoes and common food processing materials

10.5219/1408 ◽  
2020 ◽  
Vol 14 ◽  
pp. 1027-1034
Author(s):  
Oleksandr Tokarskyy ◽  
Mykhaylo Korda ◽  
Halyna Lukyantseva
Keyword(s):  
Food Processing ◽  
Risk Evaluation ◽  
Conveyor Belt ◽  
Post Inoculation ◽  
Escherichia Coli O157 ◽  
Cross Contamination ◽  
Transfer Rates ◽  
E Coli ◽  
Common Food ◽  
Special Concern

The objectives of this study were: a) to evaluate E. coli O157:H7 survival on green mature tomatoes and squares of common food processing materials – stainless steel, plastic (HDPE), and vinyl conveyor belt (PVC) – post-drying, stored at 25 ºC in the humidified environment for four days; b) to determine pathogen transfer rates (wet, 90 minutes, or 24-hours drying post-inoculation), from inoculated tomato surfaces to uninoculated steel, plastic, and vinyl conveyor belt squares and conversely. It was shown that E. coli O157:H7 did not survive well on the surface of tomatoes, resulting in a decline from 5.3 log10 CFU.mL-1 90 minutes post-drying to 1.4 log10 CFU.mL-1 on day 4. Similarly, the pathogen did not survive well on the surface of food processing squares, with numbers declining over 4 days from 4.04, 4.44, and 4.19 CFU.mL-1 of rinsate 90 minutes squares post-drying to 0.72, 0.50, 0.83  log10 CFU.mL-1, which is close to the detection limit, for the steel, vinyl belt, and plastic, respectively. Successful cross-contamination between tomatoes and food processing surfaces was achieved during wet transfer; while transfer after 90 minutes inoculum post-drying and 24 hours were less successful. This can be explained by both lack of liquid media with suspended bacteria for transfer and fast pathogen die-off after desiccation. Dry transfers, as shown by the percentage of “positive” for pathogen presence tomatoes and squares, as well as bacterial counts, were more successful from tomatoes to squares, but not conversely. Special concern raised vinyl conveyor belt, where the surface picked up the most pathogen cells from the surface of tomatoes, resulting in 100% positive during 90 minute-dry transfers, followed by plastic (66.7% positive) and steel (55.6% positive). To summarize, we presented data on the possibility of cross-contamination between mature green tomatoes and common food processing surfaces, which may be interesting for the processors for risk evaluation.

Quantifying Bacterial Cross-Contamination Rates between Fresh-Cut Produce and Hands

2017 ◽  
Vol 80 (2) ◽  
pp. 213-219 ◽  
Author(s):  
Dane A. Jensen ◽  
Michelle D. Danyluk ◽  
Linda J. Harris ◽  
Donald W. Schaffner
Keyword(s):  
Bacterial Species ◽  
Enterobacter Aerogenes ◽  
Escherichia Coli O157 ◽  
Cross Contamination ◽  
Transfer Rates ◽  
E Coli ◽  
Significant Difference ◽  
Fresh Cut ◽  
Food Safety Risk ◽  
Risk Assessment And Management

ABSTRACT This study quantifies the cross-contamination rates between fresh-cut produce and hands using a nalidixic acid–resistant nonpathogenic Enterobacter aerogenes and cocktails of rifampin-resistant Salmonella or Escherichia coli O157:H7 strains. Volunteers performed the E. aerogenes experiments (n = 20), and one of the authors performed the Salmonella and E. coli O157:H7 experiments multiple times (n =15 and n =10, respectively). Each participant handled 25 g of fresh-cut carrots, celery, or cantaloupe in two different scenarios. In the first scenario, gloved hands were inoculated with 6 log CFU per hand of the bacteria, and in the second scenario, five 25-g pieces of fresh produce were inoculated to a concentration of 6 log CFU/25 g. The glove juice method was used to quantify the bacterial concentration on the gloved hands. About 30% of E. aerogenes on gloved hands was transferred to the carrots and celery, and 18% of E. aerogenes on gloved hands was transferred to the cantaloupe. When carrots or cantaloupe was inoculated with E. aerogenes, 1% was transferred to gloved hands; from inoculated celery, about 0.3% of E. aerogenes was transferred to gloved hands. There was not a significant difference between E. aerogenes and Salmonella cross-contamination rates (P > 0.05). When gloved hands were contaminated with E. coli O157:H7, about 30% was transferred to carrots, about 10% to celery, and about 3% to cantaloupe. When carrots and celery were inoculated with E. coli O157:H7, about 1% was transferred to gloved hands, but from inoculated cantaloupe only about 0.3% was transferred. Direction of transfer (to versus from produce), difference in type of produce, and differences among the bacterial species all had significant effects on the transfer rate. Understanding transfer rates to and from fresh-cut produce will allow for better risk assessment and management of microbial food safety risk related to fresh-cut produce.

Glove Barriers to Bacterial Cross-Contamination between Hands to Food

2001 ◽  
Vol 64 (6) ◽  
pp. 845-849 ◽  
Author(s):  
REBECCA MONTVILLE ◽  
YUHUAN CHEN ◽  
DONALD W. SCHAFFNER
Keyword(s):  
Nalidixic Acid ◽  
Transfer Rate ◽  
Microbial Contamination ◽  
Enterobacter Aerogenes ◽  
Published Data ◽  
Cross Contamination ◽  
Transfer Rates ◽  
Transfer Data ◽  
High Inoculum ◽  
Bare Hand

Human hands are an important source of microbial contamination of foods. However, published data on the effectiveness of handwashing and glove use in a foodservice setting are limited. Bacterial transfer through foodservice quality gloves was quantified using nalidixic acid-resistant Enterobacter aerogenes (a nonpathogenic surrogate with attachment characteristics similar to Salmonella). Five transfer rates were determined: chicken to bare hand, chicken to hand through gloves, bare hand to lettuce, hand to lettuce through gloves (with low inoculum on hands), and hand to lettuce through gloves (with high inoculum on hands). At least 30 observations were made for each percent transfer rate using 30 individual volunteers. The logarithm of percent transfer data were then fit to distributions: chicken to bare hand, normal (0.71, 0.42); chicken to hand through gloves, gamma (5.91, 0.40, −5.00); bare hand to lettuce, logistic (1.16, 0.30); hand to lettuce through gloves (low inoculum), normal (0.35, 0.88); hand to lettuce through gloves (high inoculum), normal (−2.52, 0.61). A 0.01% transfer was observed from food to hands and from hands to food when subjects wore gloves and a 10% transfer was observed without a glove barrier. These results indicate that gloves are permeable to bacteria although transfer from hands to food through a glove barrier was less than without a glove barrier. Our results indicate that gloves may reduce both bacterial transfer from food to the hands of foodservice workers and in subsequent transfer from hands back to food.

scholarly journals Inoculum Size Influences Bacterial Cross Contamination between Surfaces

2003 ◽  
Vol 69 (12) ◽  
pp. 7188-7193 ◽  
Author(s):  
R. Montville ◽  
D. W. Schaffner
Keyword(s):  
Transfer Rate ◽  
Linear Trend ◽  
Bacterial Species ◽  
Inoculum Size ◽  
Contamination Rate ◽  
Source Surface ◽  
Cross Contamination ◽  
Inoculum Level ◽  
Transfer Rates ◽  
Initial Inoculum

ABSTRACT Many factors have been shown to influence bacterial transfer between surfaces, including surface type, bacterial species, moisture level, pressure, and friction, but the effect of inoculum size on bacterial transfer has not yet been established. Bacterial cross contamination rates during performance of common food service tasks were previously determined in our laboratory using nalidixic acid-resistant Enterobacter aerogenes. Eight different transfer rates were determined, each involving a minimum of 30 volunteers. The influence of source inoculum level on the percentage of bacteria transferred (percent transfer rates) and log10 CFU per recipient surface was determined using statistical analysis. The effect of inoculum size on transfer rate was highly statistically significant (P< 0.0001) for all transfer rate data combined (352 observations) and for each individual cross contamination rate, except for data on contamination via transfer from chicken to hand through a glove barrier (P = 0.1643). Where inoculum size on the source was greater, transfer rates were lower, and where inoculum size on the source was less, transfer rates were higher. The negative linear trend was more obvious for activities that had a larger range of inoculum sizes on the source surface. This phenomenon has serious implications for research seeking to determine bacterial cross contamination rates, since the different transfer efficiencies that were previously shown to be associated with certain activities may actually be the result of differing initial inoculum levels. The initial inoculum size on the source and the amount of bacteria transferred must both be considered to accurately determine bacterial transfer rates.

scholarly journals PSIV-11 Effects of very low-dose antibiotics on gene expression profiles in ileal mucosa of weaned pigs infected with a pathogenic E. coli

2020 ◽  
Vol 98 (Supplement_4) ◽  
pp. 286-286
Author(s):  
Kwangwook Kim ◽  
Sungbong Jang ◽  
Yanhong Liu
Keyword(s):  
Gene Expression ◽  
Systemic Inflammation ◽  
Low Dose ◽  
Expression Profiles ◽  
Gene Expression Profiles ◽  
Post Inoculation ◽  
Growth Promoter ◽  
Weaned Pigs ◽  
Ileal Mucosa ◽  
E Coli

Abstract Our previous studies have shown that supplementation of low-dose antibiotic growth promoter (AGP) exacerbated growth performance and systemic inflammation of weaned pigs infected with pathogenic Escherichia coli (E. coli). The objective of this experiment, which is extension of our previous report, was to investigate the effect of low-dose AGP on gene expression in ileal mucosa of weaned pigs experimentally infected with F18 E. coli. Thirty-four pigs (6.88 ± 1.03 kg BW) were individually housed in disease containment rooms and randomly allotted to one of three treatments (9 to 13 pigs/treatment). The three dietary treatments were control diet (control), and 2 additional diets supplemented with 0.5 or 50 mg/kg of AGP (carbadox), respectively. The experiment lasted 18 d [7 d before and 11 d after first inoculation (d 0)]. The F18 E. coli inoculum was orally provided to all pigs with the dose of 1010 cfu/3 mL for 3 consecutive days. Total RNA [4 to 6 pigs/treatment on d 5; 5 to 7 pigs/treatment on 11 post-inoculation (PI)] was extracted from ileal mucosa to analyze gene expression profiles by Batch-Tag-Seq. The modulated differential gene expression were defined by 1.5-fold difference and a cutoff of P &lt; 0.05 using limma-voom package. All processed data were statistically analyzed and evaluated by PANTHER classification system to determine the biological process function of genes in these lists. Compared to control, supplementation of recommended-dose AGP down-regulated genes related to inflammatory responses on d 5 and 11 PI; whereas, feeding low-dose AGP up-regulated genes associated with negative regulation of metabolic process on d 5, but down-regulated the genes related to immune responses on d 11 PI. The present observations support adverse effects of low-dose AGP in our previous study, indicated by exacerbated the detrimental effects of E. coli infection on pigs’ growth rate, diarrhea and systemic inflammation.

Quantification and Variability Analysis of Bacterial Cross-Contamination Rates in Common Food Service Tasks

2001 ◽  
Vol 64 (1) ◽  
pp. 72-80 ◽  
Author(s):  
YUHUAN CHEN ◽  
KRISTIN M. JACKSON ◽  
FABIOLA P. CHEA ◽  
DONALD W. SCHAFFNER
Keyword(s):  
Food Service ◽  
Enterobacter Aerogenes ◽  
Scientific Basis ◽  
Food Preparation ◽  
Contamination Rate ◽  
Cross Contamination ◽  
Transfer Rates ◽  
Washing Efficiency ◽  
The Cross ◽  
Contamination Events

This study investigated bacterial transfer rates between hands and other common surfaces involved in food preparation in the kitchen. Nalidixic acid–resistant Enterobacter aerogenes B199A was used as a surrogate microorganism to follow the cross-contamination events. Samples from at least 30 different participants were collected to determine the statistical distribution of each cross-contamination rate and to quantify the natural variability associated with that rate. The transfer rates among hands, foods, and kitchen surfaces were highly variable, being as low as 0.0005% and as high as 100%. A normal distribution was used to describe the variability in the logarithm of the transfer rates. The mean ± SD of the normal distributions were, in log percent transfer rate, chicken to hand (0.94 ± 0.68), cutting board to lettuce (0.90 ± 0.59), spigot to hand (0.36 ± 0.90), hand to lettuce (−0.12 ± 1.07), prewashed hand to postwashed hand (i.e., hand washing efficiency) (−0.20 ± 1.42), and hand to spigot (−0.80 ± 1.09). Quantifying the cross-contamination risk associated with various steps in the food preparation process can provide a scientific basis for risk management efforts in both home and food service kitchens.

187 Effects of Oligosaccharide-based Polymer on Growth Performance, Diarrhea, and Fecal β-hemolytic Coliforms in Weanling Pigs Experimentally Infected with a Pathogenic E. coli

2021 ◽  
Vol 99 (Supplement_1) ◽  
pp. 90-90
Author(s):  
Kwangwook Kim ◽  
Yijie He ◽  
Cynthia Jinno ◽  
Seijoo Yang ◽  
Xunde Li ◽  
...  
Keyword(s):  
Growth Performance ◽  
Feed Efficiency ◽  
Basal Diet ◽  
Watery Diarrhea ◽  
Experimental Unit ◽  
Post Inoculation ◽  
Weaned Pigs ◽  
E Coli ◽  
Diet Control ◽  
Dietary Treatments

Abstract The objective of this experiment was to investigate dietary supplementation of oligosaccharide-based polymer on growth performance, diarrhea, and fecal β-hemolytic coliforms of weaned pigs experimentally infected with a pathogenic F18 Escherichia coli (E. coli). Forty-eight pigs (7.23 ± 1.11 kg BW) were individually housed in disease containment rooms and randomly allotted to one of four treatments with 12 replicate pigs per treatment. The four dietary treatments were a nursery basal diet (control), and 3 additional diets supplemented with 50 mg/kg Mecadox (AGP), 10 or 20 mg/kg of oligosaccharide-based polymer. The experiment lasted 18 d [7 d before and 11 d after the first inoculation (d 0)]. The doses of F18 E. coli inoculum were 1010 cfu/3 mL oral dose daily for 3 days. Growth performance was measured on d -7 to 0 before inoculation, and d 0 to 5 and 5 to 11 post-inoculation (PI). Diarrhea score (DS; 1, normal, to 5, watery diarrhea) was daily recorded for each pig. Fecal samples were collected on d 2, 5, 8, and 11 PI to test the percentage of β-hemolytic coliforms in total coliforms. All data were analyzed by ANOVA using the PROC MIXED of SAS with pig as the experimental unit. Inclusion of oligosaccharide-based polymer linearly increased (P &lt; 0.05) ADFI on d 0 to 5 PI, and feed efficiency on d 0 to 5 PI and d 5 to 11 PI (P = 0.07), compared with the control. Supplementation of AGP or oligosaccharide-based polymer reduced (P &lt; 0.01) frequency of diarrhea of pigs from d 0 to 11 PI. No differences were observed in overall growth performance and percentage of fecal β-hemolytic coliforms on d 8 PI among pigs in AGP and oligosaccharide-based polymer treatments. In conclusion, supplementation of oligosaccharide-based polymer enhanced feed efficiency and reduced diarrhea of weaned pigs infected with a pathogenic E. coli.

scholarly journals Simulating Cross-Contamination of Cooked Pork with Salmonella enterica from Raw Pork through Home Kitchen Preparation in Vietnam

2018 ◽  
Vol 15 (10) ◽  
pp. 2324 ◽  
Author(s):  
Sinh Dang-Xuan ◽  
Hung Nguyen-Viet ◽  
Phuc Pham-Duc ◽  
Delia Grace ◽  
Fred Unger ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Household Survey ◽  
Cross Contamination ◽  
Food Handling ◽  
Transfer Rates ◽  
Handling Practices ◽  
Food Handling Practices ◽  
Cutting Boards ◽  
Insight Into ◽  
Pork Consumption

Pork is the most commonly consumed meat in Vietnam, and Salmonella enterica is a common contaminant. This study aimed to assess potential S. enterica cross-contamination between raw and cooked pork in Vietnamese households. Different scenarios for cross-contamination were constructed based on a household survey of pork handling practices (416 households). Overall, 71% of people used the same knife and cutting board for both raw and cooked pork; however, all washed their hands and utensils between handling raw and cooked pork. The different scenarios were experimentally tested. First, S. enterica was inoculated on raw pork and surfaces (hands, knives and cutting boards); next, water used for washing and pork were sampled to identify the presence and concentration of S. enterica during different scenarios of food preparation. Bootstrapping techniques were applied to simulate transfer rates of S. enterica cross-contamination. No cross-contamination to cooked pork was observed in the scenario of using the same hands with new cutting boards and knives. The probability of re-contamination in the scenarios involving re-using the cutting board after washing was significantly higher compared to the scenarios which used a new cutting board. Stochastic simulation found a high risk of cross-contamination from raw to cooked pork when the same hands, knives and cutting boards were used for handling raw and cooked pork (78%); when the same cutting board but a different knife was used, cross-contamination was still high (67%). Cross-contamination between was not seen when different cutting boards and knives were used for cutting raw and cooked pork. This study provided an insight into cross-contamination of S. enterica, given common food handling practices in Vietnamese households and can be used for risk assessment of pork consumption.

Growth of Selected Cross-Contaminating Bacterial Pathogens on Beef and Fish at 15 and 35°C+

1994 ◽  
Vol 57 (4) ◽  
pp. 337-340 ◽  
Author(s):  
AJIBOLA O. FAPOHUNDA ◽  
KENNETH W. MCMILLIN ◽  
DOUGLAS L. MARSHALL ◽  
W. M. WAITES
Keyword(s):  
Escherichia Coli ◽  
Clostridium Perfringens ◽  
Aeromonas Hydrophila ◽  
Growth Response ◽  
Cross Contamination ◽  
Limited Growth ◽  
E Coli ◽  
Fish Samples ◽  
Conditioning Temperature ◽  
The Tropics

Isolates of Escherichia coli and Clostridium perfringens from beef and Aeromonas hydrophila from fish were examined for their ability to survive and grow as cross-contaminates on nonnative tissues at simulated ambient (35°C) and aging/conditioning (15°C) temperatures of handling and retailing found in the tropics. Growth of all isolates over a 10-h period was greater (P &lt; 0.05) on their native tissues at both temperatures. The aging/conditioning temperature effectively limited growth of E. coli and A. hydrophila to less than l-logl0 CFU/g and prevented growth of C. perfringens on beef and fish samples. All three isolates demonstrated characteristic mesophilic growth response on both tissues at 35°C during the 10-h retail period. The study suggests that two muscle food products could be jointly handled to efficiently use available storage/haulage capacity in tropical countries. Potential savings in space, labor and energy would be made if cross-contamination between the two products is minimized by available packaging and sanitizing technologies.

Design of a Plane-Type Bidirectional Thermal Diode

1988 ◽  
Vol 110 (4) ◽  
pp. 299-305 ◽  
Author(s):  
K. Chen
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Transfer Rate ◽  
Reverse Bias ◽  
Energy Utilization ◽  
Heat Transfer Analysis ◽  
Transfer Rates ◽  
One Dimensional ◽  
Plane Type ◽  
Solar Energy Utilization

The design of a plane-type, bidirectional thermal diode is presented. This diode is composed of two vertical plates and several fluid-filled loops with their horizontal segments soldered to the vertical plates. This invention is simple in construction and low in cost. The direction of heat transfer in the invented thermal diode can be easily reversed. These features of the present invention make it very attractive to solar energy utilization. Natural convection analysis for thermosyphon operations was adopted for heat transfer calculations of the fluid-filled loops. A one-dimensional heat transfer analysis was employed to estimate the heat transfer rate and ratio of heat transfer rates of the diode under forward and reverse bias.

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