UV inactivation and characteristics after photoreactivation of Escherichia coli with plasmid: Health safety concern about UV disinfection

2012 ◽  
Vol 46 (13) ◽  
pp. 4031-4036 ◽  
Author(s):  
Meiting Guo ◽  
Jingjing Huang ◽  
Hongying Hu ◽  
Wenjun Liu ◽  
Jian Yang
2003 ◽  
Vol 228 (4) ◽  
pp. 331-332 ◽  
Author(s):  
Hussein S. Hussein ◽  
Stanley T. Omaye

Verotoxin-producing Escherichia coli (VTEC) have emerged in the past two decades as food-borne pathogens that can cause major outbreaks of human illnesses worldwide. The number of outbreaks has increased in recent years due to changes in food production and processing systems, eating habits, microbial adaptation, and methods of VTEC transmission. The human illnesses range from mild diarrhea to hemolytic uremic syndrome (HUS) that can lead to death. The VTEC outbreaks have been attributed to O157:H7 and non-O157:H7 serotypes of E. coli. These E. coli serotypes include motile (e.g., O26:H11 and O104:H21) and nonmotile (e.g., O111:H–,0145:H–, and O157:H–) strains. In the United States, E. coli O157:H7 has been the major cause of VTEC outbreaks. Worldwide, however, non-O157:H7 VTEC (e.g., members of the 026, O103, O111, O118, O145, and O166 serogroups) have caused approximately 30% of the HUS cases in the past decade. Because large numbers of the VTEC outbreaks have been attributed to consumption of ruminant products (e.g., ground beef), cattle and sheep are considered reservoirs of these food-borne pathogens. Because of the food safety concern of VTEC, a global perspective on this problem is addressed (Exp Biol Med Vol. 228, No. 4). The first objective was to evaluate the known non-O157:H7 VTEC strains and the limitations associated with their detection and characterization. The second objective was to identify the VTEC serotypes associated with outbreaks of human illnesses and to provide critical evaluation of their virulence. The third objective was to determine the rumen effect on survival of E. coli O157:H7 as a VTEC model. The fourth objective was to explore the role of intimins in promoting attaching and effacing lesions in humans. Finally, the ability of VTEC to cause persistent infections in cattle was evaluated.


2015 ◽  
Vol 78 (12) ◽  
pp. 2150-2155 ◽  
Author(s):  
DEAN HARAPAS ◽  
ROBERT PREMIER ◽  
BRUCE TOMKINS ◽  
GRAHAM HEPWORTH ◽  
SAID AJLOUNI

Minor shoot injury significantly (P < 0.05) increased the level at which Salmonella enterica serovar Sofia persisted on cos lettuce in the greenhouse. Initial mean counts of the Salmonella on the injured and uninjured cos lettuce were on the order of 6 log CFU/g. After 3 days, the mean count decreased to 4.8 log CFU/g on the injured plants compared with the significantly (P < 0.05) smaller count of 3.4 log CFU/g on the uninjured plants. By the end of the 3-week experiment, the count from the injured plants was 2.9 log CFU/g compared with a count of below the level of detection from the uninjured plants. A similar pattern of bacterial persistence was observed on injured versus uninjured plants by using Listeria innocua on cos lettuce and S. enterica serovar Sofia on chive. The findings reaffirm earlier results with Escherichia coli and increase the impetus to avoid shoot injury during the production of cos lettuce and chive, if bacteria of food safety concern are present.


2015 ◽  
Vol 49 (12) ◽  
pp. 7502-7503 ◽  
Author(s):  
Xin Yu ◽  
Shenghua Zhang ◽  
Chengsong Ye ◽  
Wenfang Lin ◽  
Huirong Lin ◽  
...  

2000 ◽  
Vol 63 (5) ◽  
pp. 563-567 ◽  
Author(s):  
J. R. WRIGHT ◽  
S. S. SUMNER ◽  
C. R. HACKNEY ◽  
M. D. PIERSON ◽  
B. W. ZOECKLEIN

This study examined the efficacy of UV light for reducing Escherichia coli O157:H7 in unpasteurized cider. Cider containing a mixture of acid-resistant E. coli O157:H7 (6.3 log CFU/ml) was treated using a thin-film UV disinfection unit at 254 nm. Dosages ranged from 9,402 to 61,005 μW-s/cm2. Treatment significantly reduced E. coli O157:H7 (P ≤ 0.0001). Mean reduction for all treated samples was 3.81 log CFU/ml. Reduction was also affected by the level of background microflora in cider. Results indicate that UV light is effective for reducing this pathogen in cider. However, with the dosages used in this experiment, additional reduction measures are necessary to achieve the required 5-log reduction.


2020 ◽  
Vol 64 (2) ◽  
pp. 1-10
Author(s):  
H. K. Adesokan ◽  
K. Funso-Adu ◽  
O. A. Okunlade

AbstractFoodborne pathogens are the leading cause of illness and death in developing countries and are often associated with poor hygiene and unsafe food storage conditions. Using central cold rooms with alternate power supply in preserving meats due to erratic power supply is common among meat traders in Nigeria. However, the public health safety of the operations of this practice remains un-investigated. We conducted a microbial assessment of aseptically collected meat swabs from three selected major cold rooms in Ibadan for Staphylococcus aureus, Listeria monocytogenes, Salmonella spp. and Escherichia coli using standard procedures. Antibiotic susceptibility was determined using 14 different antibiotics at standard concentrations following Kirby-Bauer Assays. The data were analysed with Stata 12.0 using bivariate and logistic regression analyses. Of 180 meat swabs collected, 42.2 % were positive for S. aureus, 22.2 % for L. monocytogenes, 20.0 % for Salmonella spp. and 6.7 % for E. coli. All of the isolates exhibited total resistance to seven of the antibiotics. Escherichia coli showed the highest resistance to 12 antibiotics, followed by Salmonella spp. (11 antibiotics), L. monocytogenes (10 antibiotics) and S. aureus (7 antibiotics). Sampling locations were significantly associated with the prevalence of L. monocytogenes (P = 0.008) and S. aureus (P = 0.000), but not with Salmonella spp. (P = 0.435) or E. coli (P = 0.117). The study revealed a heavy microbial contamination with major foodborne pathogens characterized by a high level of antibiotic resistance. These findings portend that the current operations associated with the practice of using central cold rooms in meat preservation in Nigeria undermine public health safety and need to be urgently addressed.


2016 ◽  
Vol 79 (2) ◽  
pp. 294-298 ◽  
Author(s):  
JESSIE USAGA ◽  
OLGA I. PADILLA-ZAKOUR ◽  
RANDY W. WOROBO

ABSTRACT The enhanced thermal tolerance and survival responses of Escherichia coli O157:H7 in acid and acidified foods is a major safety concern for the production of low-pH products, including beverages. Little is known about this phenomenon when using UV light treatments. This study was conducted to evaluate the effects of strain (E. coli O157:H7 strains C7927, ATCC 35150, ATCC 43895, and ATCC 43889 and E. coli ATCC 25922) and physiological state (control-unadapted, acid adapted, and acid shocked) on the UV tolerance of E. coli in apple juice treated under conditions stipulated in current U.S. Food and Drug Administration regulations. A greater than 5-log reduction of E. coli was obtained under all tested conditions. A significant effect of strain (P < 0.05) was observed, but the physiological state did not influence pathogen inactivation (P ≥ 0.05). The UV sensitivity of three spoilage microorganisms (Aspergillus niger, Penicillium commune, and Alicyclobacillus acidoterrestris) was also determined at UV doses of 0 to 98 mJ/cm2. Alicyclobacillus was the most UV sensitive, followed by Penicillium and Aspergillus. Because of the nonsignificant differences in UV sensitivity of E. coli in different physiological states, the use of an unadapted inoculum would be adequate to conduct challenge studies with the commercial UV unit used in this study at a UV dose of 14 mJ/cm2. The high UV tolerance of spoilage microorganisms supports the need to use a hurdle approach (e.g., coupling of refrigeration, preservatives, and/or other technologies) to extend the shelf life of UV-treated beverages.


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