Developing an affordable hyperspectral imaging system for rapid identification of Escherichia coli O157:H7 and Listeria monocytogenes in dairy products

Abstract

The objective of this foundational study was to develop and evaluate the efficacy of an affordable hyperspectral imaging (HSI) system to identify single and mixed strains of foodborne pathogens in dairy products. This study was designed as a completely randomized design with three replications. Three strains each of Escherichia coli O157:H7 and Listeria monocytogenes were evaluated either as single or mixed strains with the HSI system in growth media and selected dairy products (whole milk, and cottage and cheddar cheeses). Test samples from freshly prepared single or mixed strains of pathogens in growth media or inoculated dairy products were streaked onto selective media (PALCAM and/or Sorbitol MacConkey agar) for isolation. An isolated colony was selected and mixed with 1 ml of HPLC grade water, vortexed for 1 min, and spread over a microscope slide. Images were captured at 2000× magnification on the built HSI system at wavelengths ranging from 400 nm to 1100 nm with 5‐nm band intervals. For each image, three cells were selected as regions of interest (ROIs) to obtain hyperspectral signatures of respective bacteria. Reference pathogen libraries were created using growth media, and then test pathogenic cells were classified by their hyperspectral signatures as either L. monocytogenes or E. coli O157:H7 using k‐nearest neighbor (kNN) and cross‐validation technique in R‐software. With the implementation of kNN (k = 3), overall classification accuracies of 58.97% and 61.53% were obtained for E. coli O157:H7 and L. monocytogenes, respectively.

Multiplex-PCR for diagnosis of Entamoeba histolytica and Escherichia coli O157 in the patients of Wasit Province, Iraq

“…E.coli O157 appearance on MacCkonkey agar were fermented lactose, while on Sorbitol-MacCkonkey agar was diagnosed based on morphological, culture and biochemical tests, where it appeared in the form of short gram-negative bacilli and n standard lactosecontaining MacConkey Agar, so this strain is indistinguishable from other lactosefermenting E. coli. Unlike most E. coli strains, E. coli O157:H7 ferments sorbitol slowly or not at all and it lactose fermented on the MacConkey agar as shown in figure (1A) and (1B) (27), while on blood agar it appeared a typical enterohemolytic phenotype on blood agar plates after 18 to 24 h of incubation, figure (1C) (28), which is a distinctive feature of Escherichia coli from the rest of the genera of the intestinal family. On TSI culture medium E.coli O157was able to ferment glucose, lactose and sucrose, with CO2 production, bubbles and cracks and even displacement of the environment are observed, the whole tube becomes acidic and the culture medium turns yellow ( 24) figure (2).…”

Survival Behavior of Escherichia coli O157:H7 during over 60-Day Aging of Camembert Cheeses Manufactured from Unpasteurized Raw Milk

“…As a characteristic of bacteria, enterovirulent Escherichia coli in general causes acute gastroenteritis in humans [1][2][3]. One of the pathogenic E. coli is called enterohemorrhagic E. coli, of which E. coli O157:H7 is the most famous [2,4]. E. coli O157:H7 is also commonly referred to as 'O-157' for short because of its long name [1][2][3][4].…”

“…One of the pathogenic E. coli is called enterohemorrhagic E. coli, of which E. coli O157:H7 is the most famous [2,4]. E. coli O157:H7 is also commonly referred to as 'O-157' for short because of its long name [1][2][3][4]. In addition, to explain the meaning of enterohemorrhagic E. coli in detail, entero is translated as 'intestine', hemorrhagic as 'bleeding', and E. coli as 'Escherichia coli ', resulting in 'Escherichia coli ' that causes bleeding in the intestine' [4,5].…”

“…The toxin produced by O-157, called verotoxin or shiga-like toxin, is the same as or closely related to the toxin produced by Shigella dysenteriae [7,8]. As an acute disease, E. coli O157:H7 causes an acute disease called 'hemorrhagic enteritis' [1][2][3][4][5][6][7][8]. The disease is characterized by severe cramping abdominal pain and diarrhea [1][2][3][4][5][6][7][8].…”

“…As an acute disease, E. coli O157:H7 causes an acute disease called 'hemorrhagic enteritis' [1][2][3][4][5][6][7][8]. The disease is characterized by severe cramping abdominal pain and diarrhea [1][2][3][4][5][6][7][8]. Diarrhea is initially watery, but changes to bloody stools [1][2][3][4][5][6][7][8].…”