scholarly journals Application of a Bacteriophage–Sanitizer Combination in Post-Harvest Control of E. coli O157:H7 Contamination on Spinach Leaves in the Presence or Absence of a High Organic Load Produce Wash

2021 ◽  
Vol 2 (1) ◽  
pp. 12-24
Author(s):  
Badrinath Vengarai Jagannathan ◽  
Steven Kitchens ◽  
Stuart Price ◽  
Melissa Morgan ◽  
Paul Priyesh Vijayakumar

Foodborne illness due to the consumption of contaminated products continues to be a serious public health issue. Bacteriophages might provide a natural and effective way to control and reduce the pathogenic bacterial population on food products. Researchers have conducted various experiments to prove their effectiveness against different pathogens and their ability to act as a natural intervention to control pathogen populations, especially in the food industry. In this study, a cocktail of bacteriophages (phages) was added to wash water in the presence of a high organic load along with commercially used sanitizers (chlorine or Sanidate 5.0) to study the efficacy of the phage–sanitizer combination in the challenge water. It was determined that in the absence of organic loads, the sanitizer by itself or the combination with phages significantly (p < 0.001) reduced the contamination by 3.00–5.00 log CFU/mL. In the presence of organic loads, the sanitizer by itself did not contribute to a significant reduction (p > 0.05) compared to the control. However, the sanitizer–phage combination led to a 3.00-log and 6.00-log reduction (p < 0.001) of the pathogen at the end of 3 and 6 h, respectively, in the presence of high organic loads. Therefore, utilizing a combination treatment (phage–sanitizer) might be one solution to reduce pathogen contamination in the food industry, especially the fresh produce industry, thus providing safe food for consumption.

2020 ◽  
Vol 8 (9) ◽  
pp. 1316
Author(s):  
Badrinath Vengarai Jagannathan ◽  
Steven Kitchens ◽  
Paul Priyesh Vijayakumar ◽  
Stuart Price ◽  
Melissa Morgan

The increasing concern for food safety has created a need to evaluate novel techniques to eliminate or control pathogens, resulting in safe food. In this study, four bacteriophages of bovine origin, specific to E. coli O157:H7, were successfully isolated and characterized. A microplate reader assay demonstrated the efficacy of the bacteriophage (phage) cocktail against E. coli O157:H7 resulting in a significant reduction (p < 0.01) in the target pathogen population. The phage cocktail demonstrated significant efficacy (p < 0.05) against E. coli O157:H7 in the presence of the most utilized sanitizers in the United States, namely 100 parts per million (ppm) free chlorine and 100-ppm peroxyacetic acid. Survival in the sanitizer concentrations demonstrates the potential use of phage cocktail and sanitizer synergistically to enhance sanitation operations in the food industry.


1992 ◽  
Vol 55 (11) ◽  
pp. 859-861 ◽  
Author(s):  
LEEANNE JACKSON ◽  
RICHARD C. WHITING

Intrinsic and extrinsic parameters of food products, as well as bacterial population, were evaluated for their effects on the ability of Bdellovibrio bacteriovorus, a bacterium parasitic upon gram-negative bacteria, to reduce an Escherichia coli population. High concentrations of both parasite and host were the most effective for reducing a specified E. coli population. B. bacteriovorus was able to reduce the E. coli count by 90% (1 log) in &lt; 1 h at ratios of 5:1, 10:1, and 30:1 (parasite:host). Temperatures between 20 and 30°C were more conducive to bdellovibrio attack than temperatures less than 20°C. E. coli populations were reduced by more than 7-log values after 7 h of incubation at 30°C with parasite:host ratios of 2:1, 5:1, and 10:1. Greater than a 5-log reduction in the E. coli population was observed at the ratio of 30:1. B. bacteriovorus reduced the E. coli population by 1 log in approximately 24 min and 20 min at pH 7.2 and 6.8, respectively. At pH values &lt;6.8, the activity of B. bacteriovorus was diminished. These results define some of the conditions where the application of B. bacteriovorus may aid in the reduction/elimination of some gram-negative pathogens and spoilage flora that may be present in foods.


2014 ◽  
Vol 77 (10) ◽  
pp. 1669-1681 ◽  
Author(s):  
GORDON R. DAVIDSON ◽  
CHELSEA N. KAMINSKI ◽  
ELLIOT T. RYSER

Chemical sanitizers are routinely used during commercial flume washing of fresh-cut leafy greens to minimize cross-contamination from the water. This study assessed the efficacy of three chlorine treatments against Escherichia coli O157:H7 on iceberg lettuce, in wash water, and on surfaces of a pilot-scale processing line using flume water containing various organic loads. Iceberg lettuce (5.4 kg) was inoculated to contain 106 CFU/g of a 4-strain cocktail of nontoxigenic, green fluorescent protein–labeled, ampicillin-resistant E. coli O157:H7 and held for 24 h at 4°C before processing. Lettuce was shredded using a Urschel TransSlicer, step conveyed to a flume tank, washed for 90 s using water alone or one of three different sanitizing treatments (50 ppm of total chlorine either alone or acidified to pH 6.5 with citric acid or T-128) in water containing organic loads of 0, 2.5, 5, or 10% (wt/vol) blended iceberg lettuce, and then dried using a shaker table and centrifugal dryer. Next, three 5.4-kg batches of uninoculated iceberg lettuce were processed identically. Various product (25 g), water (50 ml), and equipment surface swab (100 cm2) samples were homogenized in neutralizing buffer, diluted appropriately, and plated on tryptic soy agar containing 0.6% (wt/vol) yeast extract and 100 ppm of ampicillin without prior 0.45-μm membrane filtration to quantify E. coli O157:H7. Organic load negatively impacted the efficacy of all three chlorine treatments (P &lt; 0.05) at the end of processing, with typical E. coli O157:H7 reductions of &gt;5 and 0.9 to 3.7 log CFU/ml for organic loads of 0 and 10%, respectively. Organic load rarely had a significant impact (P &lt; 0.05) on the efficacy of chlorine, chlorine plus citric acid, or chlorine plus T-128 against E. coli O157:H7 on iceberg lettuce. Reduced sanitizer efficacy generally corresponded to changes in total solids, chemical oxygen demand, turbidity, and maximum filterable volume, indicating that these tests may be effective alternatives to the industry standard of oxygen/reduction potential.


Foods ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1786
Author(s):  
György Schneider ◽  
Bettina Schweitzer ◽  
Anita Steinbach ◽  
Botond Zsombor Pertics ◽  
Alysia Cox ◽  
...  

Contamination of meats and meat products with foodborne pathogenic bacteria raises serious safety issues in the food industry. The antibacterial activities of phosphorous-fluorine co-doped TiO2 nanoparticles (PF-TiO2) were investigated against seven foodborne pathogenic bacteria: Campylobacter jejuni, Salmonella Typhimurium, Enterohaemorrhagic E. coli, Yersinia enterocolitica, Shewanella putrefaciens, Listeria monocytogenes and Staphylococcus aureus. PF-TiO2 NPs were synthesized hydrothermally at 250 °C for 1, 3, 6 or 12 h, and then tested at three different concentrations (500 μg/mL, 100 μg/mL, 20 μg/mL) for the inactivation of foodborne bacteria under UVA irradiation, daylight exposure or dark conditions. The antibacterial efficacies were compared after 30 min of exposure to light. Distinct differences in the antibacterial activities of the PF-TiO2 NPs, and the susceptibilities of tested foodborne pathogenic bacterium species were found. PF-TiO2/3 h and PF-TiO2/6 h showed the highest antibacterial activity by decreasing the living bacterial cell number from ~106 by ~5 log (L. monocytogenes), ~4 log (EHEC), ~3 log (Y. enterolcolitca, S. putrefaciens) and ~2.5 log (S. aureus), along with complete eradication of C. jejuni and S. Typhimurium. Efficacy of PF-TiO2/1 h and PF-TiO2/12 h NPs was lower, typically causing a ~2–4 log decrease in colony forming units depending on the tested bacterium while the effect of PF-TiO2/0 h was comparable to P25 TiO2, a commercial TiO2 with high photocatalytic activity. Our results show that PF-co-doping of TiO2 NPs enhanced the antibacterial action against foodborne pathogenic bacteria and are potential candidates for use in the food industry as active surface components, potentially contributing to the production of meats that are safe for consumption.


2021 ◽  
Vol 14 (5) ◽  
pp. 414
Author(s):  
Neda Aničić ◽  
Uroš Gašić ◽  
Feng Lu ◽  
Ana Ćirić ◽  
Marija Ivanov ◽  
...  

Two Balkan Peninsula endemics, Nepeta rtanjensis and N. argolica subsp. argolica, both characterized by specialized metabolite profiles predominated by iridoids and phenolics, are differentiated according to the stereochemistry of major iridoid aglycone nepetalactone (NL). For the first time, the present study provides a comparative analysis of antimicrobial and immunomodulating activities of the two Nepeta species and their major iridoids isolated from natural sources—cis,trans-NL, trans,cis-NL, and 1,5,9-epideoxyloganic acid (1,5,9-eDLA), as well as of phenolic acid rosmarinic acid (RA). Methanol extracts and pure iridoids displayed excellent antimicrobial activity against eight strains of bacteria and seven strains of fungi. They were especially potent against food-borne pathogens such as L. monocytogenes, E. coli, S. aureus, Penicillium sp., and Aspergillus sp. Targeted iridoids were efficient agents in preventing biofilm formation of resistant P. aeruginosa strain, and they displayed additive antimicrobial interaction. Iridoids are, to a great extent, responsible for the prominent antimicrobial activities of the two Nepeta species, although are probably minor contributors to the moderate immunomodulatory effects. The analyzed iridoids and RA, individually or in mixtures, have the potential to be used in the pharmaceutical industry as potent antimicrobials, and in the food industry to increase the shelf life and safety of food products.


2000 ◽  
Vol 63 (6) ◽  
pp. 703-708 ◽  
Author(s):  
MARCY A. WISNIEWSKY ◽  
BONITA A. GLATZ ◽  
MARK L. GLEASON ◽  
CHERYLL A. REITMEIER

The objectives of this study were to determine if washing of whole apples with solutions of three different sanitizers (peroxyacetic acid, chlorine dioxide, or a chlorine-phosphate buffer solution) could reduce a contaminating nonpathogenic Escherichia coli O157:H7 population by 5 logs and at what sanitizer concentration and wash time such a reduction could be achieved. Sanitizers were tested at 1, 2, 4, 8, and 16 times the manufacturer's recommended concentration at wash times of 5, 10, and 15 min. Whole, sound Braeburn apples were inoculated with approximately 1 × 108 or 7 × 106 CFU per apple, stored for 24 h, then washed with sterile water (control) or with sanitizers for the prescribed time. Recovered bacteria were enumerated on trypticase soy agar. Washing with water alone reduced the recoverable population by almost 2 logs from the starting population; this can be attributed to physical removal of organisms from the apple surface. No sanitizer, when used at the recommended concentration, reduced the recovered E. coli population by 5 logs under the test conditions. The most effective sanitizer, peroxyacetic acid, achieved a 5-log reduction when used at 2.1 to 14 times its recommended concentration, depending on the length of the wash time. The chlorine-phosphate buffer solution reduced the population by 5 logs when used at 3 to 15 times its recommended concentration, depending on wash time. At no concentration or wash time tested did chlorine dioxide achieve the 5-log reduction.


1989 ◽  
Vol 52 (8) ◽  
pp. 595-601 ◽  
Author(s):  
EWEN C. D. TODD

Although the full economic impact of foodborne diseases has yet to be measured, preliminary studies show that the cost of illness, death, and business lost is high indeed. This impact is probably greatest in developing countries, but few facts are known. For the United States, preliminary estimates are 12.6 million cases costing $8.4 billion. These may seem excessive but other authors have postulated even higher case and dollar figures. Microbiological diseases (bacterial and viral) represent 84% of the United States' costs, with salmonellosis and staphylococcal intoxication being the most economically important diseases (annually $4.0 billion and $1.5 billion, respectively). Other costly types of illnesses are toxoplasmosis ($445 million), listeriosis ($313 million), campylobacteriosis ($156 million), trichinosis ($144 million), Clostridium perfringens enteritis ($123 million), and E. coli infections including hemorrhagic colitis ($223 million). Botulism has a high cost per case ($322,200), but its total impact is only $87 million because relatively few cases occur (270). This is because the food industry has been able to introduce effective control measures. Salmonellosis, however, is much more widespread (2.9 million cases) and affects all sectors of the food industry.


2008 ◽  
Vol 71 (7) ◽  
pp. 1401-1405 ◽  
Author(s):  
JEREMY A. OBRITSCH ◽  
DOJIN RYU ◽  
LUCINA E. LAMPILA ◽  
LLOYD B. BULLERMAN

The antimicrobial activities of four long-chain food-grade polyphosphates were studied at concentrations allowed in the food industry (&lt;5,000 ppm) in defined basal media by determining the inhibition of growth of three gram-negative and four gram-positive spoilage and pathogenic bacteria. Both generation time and lag phase of Escherichia coli K-12, E. coli O157: H7, and Salmonella Typhimurium were increased with all of the polyphosphates tested. Bacillus subtilis and Staphylococcus aureus were more sensitive to polyphosphates, but not in all cases, with multiphased growth. The growth of Lactobacillus plantarum was inhibited by polyphosphates at concentrations above 750 ppm, but the lag time of Listeria monocytogenes was shortened by the presence of polyphosphates. No single polyphosphate was maximally inhibitory against all bacteria. Polyphosphates with chain lengths of 12 to 15 were significantly different from those with chain lengths of 18 to 21 depending on the organism and concentrations of polyphosphate used. Overall, higher polyphosphate concentrations resulted in greater inhibition of bacterial growth.


2002 ◽  
Vol 65 (8) ◽  
pp. 1215-1220 ◽  
Author(s):  
CHIA-MIN LIN ◽  
SARAH S. MOON ◽  
MICHAEL P. DOYLE ◽  
KAY H. McWATTERS

Iceberg lettuce is a major component in vegetable salad and has been associated with many outbreaks of foodborne illnesses. In this study, several combinations of lactic acid and hydrogen peroxide were tested to obtain effective antibacterial activity without adverse effects on sensory characteristics. A five-strain mixture of Escherichia coli O157:H7, Salmonella enterica serotype Enteritidis, and Listeria monocytogenes was inoculated separately onto fresh-cut lettuce leaves, which were later treated with 1.5% lactic acid plus 1.5% hydrogen peroxide (H2O2) at 40°C for 15 min, 1.5% lactic acid plus 2% H2O2 at 22°C for 5 min, and 2% H2O2 at 50°C for 60 or 90 s. Control lettuce leaves were treated with deionized water under the same conditions. A 4-log reduction was obtained for lettuce treated with the combinations of lactic acid and H2O2 for E. coli O157:H7 and Salmonella Enteritidis, and a 3-log reduction was obtained for L. monocytogenes. However, the sensory characteristics of lettuce were compromised by these treatments. The treatment of lettuce leaves with 2% H2O2 at 50°C was effective not only in reducing pathogenic bacteria but also in maintaining good sensory quality for up to 15 days. A ≤4-log reduction of E. coli O157:H7 and Salmonella Enteritidis was achieved with the 2% H2O2 treatment, whereas a 3-log reduction of L. monocytogenes was obtained. There was no significant difference (P &gt; 0.05) between pathogen population reductions obtained with 2% H2O2 with 60- and 90-s exposure times. Hydrogen peroxide residue was undetectable (the minimum level of sensitivity was 2 ppm) on lettuce surfaces after the treated lettuce was rinsed with cold water and centrifuged with a salad spinner. Hence, the treatment of lettuce with 2% H2O2 at 50°C for 60 s is effective in initially reducing substantial populations of foodborne pathogens and maintaining high product quality.


Plants ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 2669
Author(s):  
Michaela Barkociová ◽  
Jaroslav Tóth ◽  
Katarzyna Sutor ◽  
Natalia Drobnicka ◽  
Slawomir Wybraniec ◽  
...  

Epiphyllum, Hylocereus, and Opuntia plants belong to the Cactaceae family. They are mostly known as ornamental plants but also for their edible fruits, which can potentially be sources of betalains, such as betanin, a natural pigment used in the food industry, e.g., under the European label code E 162. The aim of this work was the identification of betalains (using LC-MS/MS), evaluation of total betalain content (spectrophotometrically), analysis of functional groups (using FT-IR), evaluation of antioxidant activity (using DPPH, ABTS, FRAP, DCFH-DA, and reducing power methods) and evaluation of antimicrobial activity (S. aureus, E. coli, and C. albicans) in fruits of Epiphyllum, Hylocereus, and Opuntia taxa. A total of 20 betalains were identified in the studied Cactaceae fruits. The Epiphyllum pink hybrid had the highest values of total betalains amongst all samples. The highest antioxidant activity was observed in the Epiphyllum pink hybrid, in Opuntia zacuapanensis and O. humifusa fruits. The antimicrobial activity assay showed that cacti fruits were not able to effectively inhibit the growth of E. coli, S. aureus, or C. albicans. Our results prove that these fruits are good sources of natural pigments—betalains. They do not contain toxic compounds in significant amounts and they exhibit antioxidant activity.


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