Shiga toxin-producing Escherichia coli (STEC) O145 is one of the most prevalent non-O157 serogroups associated with foodborne outbreaks. Lytic phages are a potential alternative to antibiotics in combatting bacterial pathogens. In this study, we characterized a Siphoviridae phage lytic against STEC O145 strains as a novel antimicrobial agent. Escherichia phage vB_EcoS-Ro145clw (Ro145clw) was isolated and purified prior to physiological and genomic characterization. Then, in vitro antimicrobial activity against an outbreak strain, E. coli O145:H28, was evaluated. Ro145clw is a double-stranded DNA phage with a genome 42,031 bp in length. Of the 67 genes identified in the genome, 21 were annotated with functional proteins, none of which were stx genes. Ro145clw had a latent period of 21 min and a burst size of 192 phages per infected cell. The phage could sustain a wide range of pH (pH 3 to pH 10) and temperatures (−80 °C to −73 °C). Ro145clw was able to reduce E. coli O145:H28 in lysogeny broth by approximately 5 log at 37 °C in four hours. These findings indicate that the Ro145clw phage is a promising antimicrobial agent that can be used to control E. coli O145 in adverse pH and temperature conditions.

Shiga toxin-producing Escherichia coli (STEC) O103 strains have been recently attributed to various foodborne outbreaks in the United States. Due to the emergence of antibiotic-resistant strains, lytic phages are considered as alternative biocontrol agents. This study was to biologically and genomically characterize two STEC O103-infecting bacteriophages, vB_EcoP-Ro103C3lw (or Ro103C3lw) and vB_EcoM-Pr103Blw (or Pr103Blw), isolated from an organic farm. Based on genomic and morphological analyses, phages Ro103C3lw and Pr103Blw belonged to Autographiviridae and Myoviridae families, respectively. Ro103C3lw contained a 39,389-bp double-stranded DNA and encoded a unique tail fiber with depolymerase activity, resulting in huge plaques. Pr103Blw had an 88,421-bp double-stranded DNA with 26 predicted tRNAs associated with the enhancement of the phage fitness. Within each phage genome, no virulence, antibiotic-resistant, and lysogenic genes were detected. Additionally, Ro103C3lw had a short latent period (2 min) and a narrow host range, infecting only STEC O103 strains. By contrast, Pr103Blw had a large burst size (152 PFU/CFU) and a broad host range against STEC O103, O26, O111, O157:H7, and Salmonella Javiana strains. Furthermore, both phages showed strong antimicrobial activities against STEC O103:H2 strains. The findings provide valuable insight into these two phages’ genomic features with the potential antimicrobial activities against STEC O103.

Over recent years, the food industry has striven to reduce waste, mostly because of rising awareness of the detrimental environmental impacts of food waste. While the edible oils market (mostly represented by soybean oil) is forecasted to reach 632 million tons by 2022, there is increasing interest to produce non-soybean, plant-based oils including, but not limited to, coconut, flaxseed and hemp seed. Expeller pressing and organic solvent extractions are common methods for oil extraction in the food industry. However, these two methods come with some concerns, such as lower yields for expeller pressing and environmental concerns for organic solvents. Meanwhile, supercritical CO2 and enzyme-assisted extractions are recognized as green alternatives, but their practicality and economic feasibility are questioned. Finding the right balance between oil extraction and phytochemical yields and environmental and economic impacts is challenging. This review explores the advantages and disadvantages of various extraction methods from an economic, environmental and practical standpoint. The novelty of this work is how it emphasizes the valorization of seed by-products, as well as the discussion on life cycle, environmental and techno-economic analyses of oil extraction methods.

Bacteriophages (or phages) specific to Shiga toxin-producing E. coli (STEC) strains are frequently isolated from animal-associated environments primarily because ruminant animals are the natural reservoir of STEC. However, little is known about these phages in produce-growing environments. The objective of this study was to determine the effects of environmental factors on the prevalence of the phages lytic against O157 and the top 6 non-O157 STEC on an organic farm.A total of 370 samples were collected from an organic farm, containing animal-active and producegrowing areas for one year. A bacterial cocktail, including non-pathogenic and pathogenic E. coli strains, was used for phage isolation. Meanwhile, culture methods and PCR were used to isolate STEC strains. Weather information was also collected for each sampling trip. Twenty-eight samples contained the phages lytic against STEC (or STEC-infecting phages), of which 26 were collected from the animal-active area. Moreover, the winter season had a higher phage prevalence than other seasons likely due to high rain precipitation. The phages belonging to the Myoviridae family and those lytic against STEC O103 were the most prevalent. One E. coli O103:H2 was isolated from a water sample where no STEC O103-infecting phages were found. Additionally, no STEC O103 was present in the samples containing STEC O103-infecting phages. The findings indicate that animal is the primary factor contributing to the prevalence of the STEC-infecting phages in the surrounding environment of the organic farm, and the presence of these phages contributes to the negative correlation with their STEC hosts.

No abstract