Research Publications (Food Safety)

The use of a yeast cell wall extract derived from Saccharomyces cerevisiae (Actigen®) has been proposed as an alternative to in-feed antibiotics. This experiment was conducted to investigate the efficacy of yeast cell extract as an alternative to zinc bacitracin or salinomycin using a necrotic enteritis challenge model. A feeding study was conducted using 480-day-old male Ross 308 chicks assigned to 48 floor pens. A 2 x 4 factorial arrangement of treatments was employed.

The effect of global antibiotic use practices in livestock on the emergence of antibiotic resistant pathogens is poorly understood. There is a paucity of data among African nations, which suffer from high rates of antibiotic resistant infections among the human population. Escherichia (29.5%), Staphylococcus (15.8%), and Proteus (15.79%) were the dominant bacterial genera isolated from chicken litter from four different farms in Zaria, Nigeria, all of which contain human pathogenic members.

In this study, a dual priming oligonucleotide (DPO)-based multiplex PCR assay was developed for the specific detection of four foodborne diarrheagenic Escherichia coli (DEC) in food, including enterotoxigenic E. coli (ETEC), enteropathogenic E. coli (EPEC), enterohemorrhagic E. coli (EHEC) O157:H7 and enteroinvasive E. coli (EIEC). Species-specific DPO primers were designed based on rfbE, LT, ipaH and bfpA genes for EHEC O157:H7, ETEC, EIEC and EPEC, respectively.

The physical, optical, antimicrobial and antioxidant properties of jellyfish protein (JFP) films with added transglutaminase (TGase) and wasabi extract (WE) were studied. Among the plasticisers, 30% sorbitol was the most desirable. The optimal physical properties of the JFP films were obtained when 15 U transglutaminase g−1 JFP was added. The incorporation of WE affected the physical properties of the JFP films.

Cellulose is the most abundant organic polymer on Earth. In bacteria, cellulose confers protection against environmental insults and is a constituent of biofilms typically formed on abiotic surfaces. We report that, surprisingly, Salmonella enterica serovar Typhimurium makes cellulose when inside macrophages. We determine that preventing cellulose synthesis increases virulence, whereas...

The occurrence of outbreaks of Cronobacter sakazakii causing necrotizing meningitis in China highlights the need for strain characterization of this pathogenic species. In this study, SMM system was utilized to mine for new molecular markers of C. sakazakii. One C. sakazakii-specific CDS (>ref|NC_009778.1|:c1077329-1076055) with a length of 1,275 bp was used to design a primer set. A PCR assay was developed and optimized to detect C. sakazakii.

Noroviruses are the most common causative agent of viral gastroenteritis in humansand are responsible for major foodborne illnesses in the United States. Filter-feeding molluscan shellfish exposed to sewage-contaminated waters bioaccumulate viruses, and if consumed raw, transmit the viruses to humans and cause illness.

Adrianna Raczkowska, Joanna Trzos, Olga Lewandowska, Marta Nieckarz, Katarzyna Brzostek

The role of chromosomal toxin-antitoxin (TA) systems, ubiquitous within the genomes of free-living bacteria, is still debated. We have scanned the Vibrio cholerae N16961 genome for class 2 TA genes and identified 18 gene-pair candidates. Interestingly, all but one are located in the chromosome 2 superintegron (SI). The single TA found outside of the SI is located on chromosome 1 and is related to the well-characterized HipAB family known to play a role in antibiotic persistence.

Publication date: Available online 17 April 2015

Author(s): Gerjo J. de Knegt , Irma A.J.M. Bakker-Woudenberg , Dick van Soolingen , Rob Aarnoutse , Martin J. Boeree , Jurriaan E.M. de Steenwinkel

Foodborne Pathogens and Disease , Vol. 0, No. 0.

Tobias Dörr, Brigid M. Davis, Matthew K. Waldor

Aim
To examine the occurrence and quantity of potential pathogens and an indicator of microbial contamination in the sediments of municipal drinking water storage tanks (MDWSTs), given the absence of such data across the United States.

Among 56 blood isolates of Vibrio species identified by sequencing analysis of 16S rRNA and rpoB genes, the Bruker Biotyper matrix-assisted laser desorption ionization–time of flight mass spectrometry (MALDI-TOF MS) system correctly identified all isolates of Vibrio vulnificus (n = 20), V. parahaemolyticus (n = 2), and V. fluvialis (n = 1) but none of the isolates of serogroup non-O1/O139 (non-serogroup O1, non-O139) V. cholerae (n = 33) to the species level.

Shiga toxin-producing Escherichia coli (STEC) is an enteropathogen of public health concern because of its ability to cause serious illness and outbreaks. In this prospective study, a diagnostic screening algorithm to categorize STEC infections into risk groups was evaluated. The algorithm consists of prescreening stool specimens with real-time PCR (qPCR) for the presence of stx genes.

Diarrhea due to enteric bacterial pathogens causes significant morbidity and mortality in the United States and worldwide. However, bacterial pathogens may be infrequently identified. Currently, culture and enzyme immunoassays (EIAs) are the primary methods used by clinical laboratories to detect enteric bacterial pathogens.

Serotyping forms the basis of national and international surveillance networks for Salmonella, one of the most prevalent foodborne pathogens worldwide ( 1 – 3 ). Public health microbiology is currently being transformed by whole-genome sequencing (WGS), which opens the door to serotype determination using WGS data.

Cronobacter species are foodborne pathogens associated with neonatal meningitis, sepsis and necrotizing enterocolitis through consumption of contaminated powdered milk. However, there are no specific targets used for differentiating Cronobacter species. The DNA-based assay and polyphasic analysis have facilitated the detection and typing of Cronobacter species in foodborne outbreaks. In this study, polymerase chain reaction (PCR) and dot hybridization for detecting Cronobacter spp.

Following a large outbreak of Shiga toxin-producing Escherichia coli (STEC) O157 infection in 2012, the prerequisite program for the production of pickles in Japan was revised to include disinfection with sodium hypochlorite (NaClO). Here, we examined the indicator bacterial counts, incidence of STEC and Salmonella spp.

Sarah A. Jung, Christine A. Chapman, Wai-Leung Ng

Response surface methodology was applied to investigate the combined effect of apple skin polyphenolsASP), acetic acid (AA), oregano essential oil (O) and carvacrol (C) on the inactivation of Salmonella on sliced cooked ham. A full factorial experimental design was employed with control variables of ASP (0–10%), AA (0–4%), O (0–0.6%) and C (0–0.8%).

Second messengers are key components of many signal transduction pathways. In addition to cyclic AMP, ppGpp, and cyclic di-GMP, many bacteria use also cyclic di-AMP as a second messenger. This molecule is synthesized by distinct classes of diadenylate cyclases and degraded by phosphodiesterases. The control of the intracellular c-di-AMP pool is very important since both a lack of this molecule and its accumulation can inhibit growth of the bacteria.

A real-time loop-mediated isothermal amplification (RealAmp) assay for the detection of Listeria was developed. The RealAmp assay, using primers specific for the hemolysin-encoding hlyA gene, was verified using Listeria monocytogenes strains (n = 58) from different regions of the world. Both the sensitivity and specificity of the RealAmp assay were high. The RealAmp assay could detect 103 CFU ml−1 within 30 min.

In this study, a duplex qPCR assay was developed for the needs of the Irish fish industry to screen for the two major food-borne pathogens of fish, Listeria monocytogenes and Escherichia coli O157:H7. The assay can claim positive or negative results for two pathogens in one go in only 20 hours including 16 hour universal pre-enrichment and compared to traditional ISO approved plate culture methods the labor and the cost involved in testing of one sample is reduced to minimum.