Candidate genes associated with fatty acid compositions in north American Atlantic salmon (Salmo salar).

Fatty acids are a requirement for normal development, however, since humans are unable to de novo produce essential fatty acids, they must be obtained from diet. Atlantic salmon is a major dietary source of nutritious and digestible fatty acids. Here, we set out to uncover the genomic basis of individual fatty acids and indices (saturated fatty acids, monounsaturated fatty acids, polyunsaturated fatty acids, n-3, and n-6) in 208 North American Atlantic salmon, to understand selection potential toward increasing relative quantities of essential fatty acids and to identify candidate genes for future research.

Stress Resistance and Virulence Gene Profiles Associated with Phylogeny and Phenotypes of Escherichia coli from Cattle.

Seven serogroups of E. coli (Top seven E. coli) are frequently implicated in foodborne outbreaks in North America, largely due to their carriage of Shiga toxin genes (stx).

Microbial Dynamics in Mixed-Culture Biofilms of Typhimurium and O157:H7 and Bacteria Surviving Sanitation of Conveyor Belts of Meat Processing Plants.

Biofilm formation can lead to the persistence of Typhimurium (ST) and O157:H7 (O157). This study investigated the impact of meat processing surface bacteria (MPB) on biofilm formation by O157 (non-biofilm former; NF) and ST (strong biofilm former; BF). MPB were recovered from the contacting surfaces (CS), non-contacting surfaces (NCS), and roller surfaces (RS) of a beef plant conveyor belt after sanitation.

Lactic Acid Resistance and Population Structure of Escherichia coli from Meat Processing Environment.

To explore the effect of beef processing on Escherichia coli populations in relation to lactic acid resistance, this study investigated the links among acid response, phylogenetic structure, genome diversity, and genotypes associated with acid resistance of meat plant E. coli. Generic E.

Biofilm formation by Non-O157 Shiga toxin-producing Escherichia coli in monocultures and co-cultures with meat processing surface bacteria.

This study investigated the impact of meat processing surface bacteria (MPB) on biofilm formation by non-O157 Shiga toxin-producing Escherichia coli (STEC), and potential links between biofilm formation by STEC and biofilm-related genes in their genomes. Biofilm development by 50 MPB and 6 STEC strains in mono- and co-cultures was assessed by the crystal violet staining method, and their expression of curli and cellulose was determined using the Congo red agar method. Genes (n = 141) associated with biofilm formation in the STEC strains were profiled.

Effects of Peroxyacetic Acid Spray and Storage Temperature on the Microbiota and Sensory Properties of Vacuum-Packed Subprimal Cuts of Meat.

We investigated the impact of peroxyacetic acid (PAA; 200 ppm) spray on the microbiota and shelf life of commercial, vacuum-packed beef stored at chiller temperatures. Ribeye cuts ( = 147) were collected from a local beef plant on the day of production for two consecutive days, with one set collected at the start of work with the PAA spray nozzles turned off (control) and during routine production with the PAA spray nozzles turned on (PAA) each day. Packs were stored at 4, 2, and -1°C for up to 34, 104, and 180 days and sampled at appropriate intervals for sensory assessment, microbial enumeration, and microbial profiling by 16S rRNA gene amplicon analysis.

Transcriptome Analysis of Listeria monocytogenes Exposed to Beef Fat Reveals Antimicrobial and Pathogenicity Attenuation Mechanisms.

is a deadly intracellular pathogen mostly associated with consumption of ready-to-eat foods. This study investigated the effectiveness of total beef fat (BF-T) from flaxseed-fed cattle and its fractions enriched with monounsaturated fatty acids (BF-MUFA) and polyunsaturated fatty acids (BF-PUFA), along with commercially available long-chain fatty acids (LC-FA), as natural antimicrobials against BF-T was ineffective at concentrations up to 6 mg/ml, while was susceptible to BF-MUFA and BF-PUFA, with MICs at pH 7 of 0.33 ± 0.

Effects of a novel three-step sous-vide cooking and subsequent chilled storage on the microbiota of beef steaks.

This study aimed to evaluate a novel three-step sous-vide (SV) method on bacterial growth and diversity, and its relationship to product storage life. Vacuum-packed naturally contaminated steaks were sequentially cooked at 39 °C (1 h), 49 °C (1 h), and 59 °C (4 h), then stored at -1.5 and 2 °C for 28 d, with a single-step SV at 59 °C for 4 h for comparison.

Facultative Anaerobes Shape Multispecies Biofilms Composed of Meat Processing Surface Bacteria and Escherichia coli O157:H7 or Salmonella enterica Serovar Typhimurium.

This study investigated the microbial dynamics in multispecies biofilms of O157:H7 strain 1934 (O157) or serovar Typhimurium ATCC 14028 (ST) and 40 strains of meat processing surface bacteria (MPB). Biofilms of O157 or ST with/without MPB were developed on stainless steel coupons at 15°C for up to 6 days. Bacteria in suspensions (inoculum, days 2 and 6) and biofilms (days 2 and 6) were enumerated by plating.

Relative response of populations of Escherichia coli and Salmonella enterica to exposure to thermal, alkaline and acidic treatments.

We evaluated the relative response of generic Escherichia coli (GEC), Shiga toxin-producing E. coli (STEC) and Salmonella enterica to heat, alkaline or acid treatments. GEC included strains from carcasses (n = 24) and trim (n = 25) at a small beef plant where no decontamination interventions are used and at a large plant where multiple decontamination interventions are used (carcass n = 25 and trim n = 25).

Comparative assessment of qPCR enumeration methods that discriminate between live and dead Escherichia coli O157:H7 on beef.

Quantitative Polymerase Chain Reaction (qPCR) is a molecular method commonly used to detect and quantify bacterial DNA on food but is limited by its inability to distinguish between live and dead cell DNA. To overcome this obstacle, propidium monoazide (PMA) alone or with deoxycholate (DC) was used to prevent dead cell detection in qPCR. qPCR methods were used to detect strains of Escherichia coli O157, which can cause infection in humans with an infectious dose of less than 10 cells.

Dynamics of Biofilm Formation by Salmonella Typhimurium and Beef Processing Plant Bacteria in Mono- and Dual-Species Cultures.

This study aimed to determine the impact of bacteria from a beef plant conveyor belt on the biofilm formation of Salmonella in dual-species cultures. Beef plant isolates (50) including 18 Gram-negative aerobes (GNA), 8 Gram-positive aerobes (GPA), 5 lactic acid bacteria (LAB), 9 Enterobacteriaceae (EB), and 10 generic Escherichia coli (GEC) were included for developing biofilms in mono- and co-culture with S. Typhimurium at 15 °C for 6 days.

Inactivation of Escherichia coli O157:H7 in Minute Steaks Cooked under Selected Conditions.

A national survey was conducted in Canada to determine consumer cooking practices for minute steaks (thin, mechanically tenderized beef cutlets). Results indicate that most Canadians prefer cooking minute steaks by pan frying and to a medium level of doneness. To identify safe cooking conditions, retail minute steaks (∼125 g), inoculated at three sites per steak with a five-strain cocktail of nontoxigenic Escherichia coli O157:H7 (6.