Research Publications (Food Safety)

Various compounds found in peanutArachis hypogaea) have been shown to provide multiple benefits to human health and may influence the growth of a broad range of gut bacteria. In this study, we investigated the effects of peanut white kernel and peanut skin on 3 strains of Lactobacillus and 3 major foodborne enteric bacterial pathogens.

The aim of this study was to evaluate the performance of immunodetection methods and PCR analysis of enterotoxigenic Bacillus cereus strains. Methods and Results Eighty-eight enterotoxigenic B. cereus group strains linked to foodborne outbreaks and illnesses were studied with 30 exclusivity non-enterotoxigenic strains including B. amyoliquifaciens, B. subtilis, S. aureus, Salmonella, and E. coli for this assessment.

The ability to form biofilms is critical for environmental survival and transmission of Vibrio cholerae, a facultative human pathogen responsible for the disease cholera. Biofilm formation is controlled by several transcriptional regulators and alternative sigma factors. In this study, we report that the two main positive regulators of biofilm formation, VpsR and VpsT bind to non-overlapping target sequences in the regulatory region of vpsL in vitro.

Publication date: July 2015
, Volume 53
Author(s): A. Rebecchi , V. Pisacane , M.L. Callegari , E. Puglisi , L. Morelli

Because of their small size, bacterial cells have long kept details about their inner workings a secret. We are starting to decipher their mechanistic secrets, in no small part due to the development of single-molecule and super-resolution fluorescence imaging, the subject of the 2014 Nobel Prize in Chemistry. These new methods have yielded a surge of discoveries about the subcellular organization and dynamics inside microbes.

The Rid family of proteins is highly conserved and broadly distributed throughout the domains of life. Genetic and biochemical studies, primarily in Salmonella enterica, have defined a role for RidA in responding to endogenously generated reactive metabolites. The data show that 2-aminoacrylate (2AA), a reactive enamine intermediate generated by some pyridoxal 5'-phosphate (PLP)-dependent enzymes, accumulates in the absence of RidA.

The food safety criteria that have been incorporated in European regulation (EC) N°2073/2005 (Commission regulation, 2005), for Listeria monocytogenes in ready-to eat (RTE) foods, specify a maximum allowable concentration of 100 cfu.g−1 or ml−1. Some factors such as pH, salt and modified atmosphere packaging (MAP) are used to prevent the growth of L. monocytogenes in order to comply with the limit. Interactions between background microflora (BM) and L.

One unreported case of extended-spectrum-beta-lactamase (ESBL)-producing Salmonella enterica serovar Typhi was identified, whole-genome sequence typed, among other analyses, and compared to other available genomes of S. Typhi. The reported strain was similar to a previously published strain harboring blaSHV-12 from the Philippines and likely part of an undetected outbreak, the first of ESBL-producing S. Typhi.

While the differential association of Escherichia coli O157 genotypes with animal and human hosts has recently been well documented, little is known about their distribution between countries and how this might affect regional disease rates. Here, we used a 48-plex single nucleotide polymorphism (SNP) assay to segregate 148 E. coli O157 isolates from Australia, Argentina, and the United States into 11 SNP lineages.

Human infection with Shiga toxin-producing Escherichia coli (STEC) is a major cause of postdiarrheal hemolytic-uremic syndrome (HUS), a life-threatening condition characterized by hemolytic anemia, thrombocytopenia, and acute renal failure. E. coli O157:H7 is the dominant STEC serotype associated with HUS worldwide, although non-O157 STEC serogroups can cause a similar disease. The detection of anti-O157 E.

Strains of Escherichia coli O26:H11 that were positive for stx2 alone (n = 23), which were not epidemiologically related or part of an outbreak, were isolated from pediatric patients in France between 2010 and 2013. We were interested in comparing these strains with the new highly virulent stx2a-positive E.

We encountered a rare case of severe fatal infection in a 70-year-old woman due to Campylobacter upsaliensis, identified by PCR amplification and sequencing analysis of the 16S rRNA gene using DNA extracted from the isolates. To our knowledge, fatal sepsis due to this organism has never been described to date.

An unusual increase in the number of Campylobacter concisus isolates found in stool cultures provoked an outbreak investigation at Bern University Hospital. No epidemiological links were found between the cases, and the Campylobacter isolates were clonally unrelated. A change in culture conditions to a hydrogen-rich atmosphere enhancing growth of C. concisus was deemed responsible for this pseudo-outbreak.

Most infant botulism cases worldwide are due to botulinum toxin types A and B. Rarely, Clostridium botulinum strains that produce two serotypes (Ab, Ba, and Bf) have also been isolated from infant botulism cases. This is the first reported case of infant botulism due to C. botulinum type Af worldwide.

An outbreak of human botulism was due to consumption of ham containing botulinum neurotoxins B and E. A Clostridium botulinum type E strain isolated from ham was assigned to a new subtype (E12) based on bont/E gene sequencing and belongs to a new multilocus sequence subtype, as analyzed by whole-genome sequencing.

The prebiotic effect of inulin added to MRS medium on growth and bacteriocin production by L. plantarum ST16 Pa was investigated in stationary cultures in anaerobic jars with medium containing 0.025% sodium thioglycolate or in flasks shaken at 100 rpm. In the presence of 1% inulin in anaerobic stationary cultures, this strain produced lactic acid at a level that was 36.5% higher than in the absence of the polysaccharide.

Publication date: 16 March 2015
, Volume 197
Author(s): M.J. Vilar , S. Virtanen , R. Laukkanen-Ninios , H. Korkeala

Publication date: June 2015
, Volume 48
Author(s): Vinayak Ghate , Ai Ling Leong , Amit Kumar , Woo Suk Bang , Weibiao Zhou , Hyun-Gyun Yuk

Publication date: 16 March 2015
, Volume 197
Author(s): Rowaida K.S. Khalil , Mohamed A.E. Gomaa , Mahmoud I.M. Khalil

Publication date: June 2015
, Volume 48
Author(s): Maryam Alnoman , Pathima Udompijitkul , Daniel Paredes-Sabja , Mahfuzur R. Sarker

Publication date: June 2015
, Volume 48
Author(s): Laurel S. Burall , Alexandra C. Simpson , Luoth Chou , Pongpan Laksanalamai , Atin R. Datta

Publication date: June 2015
, Volume 48
Author(s): Amin N. Olaimat , Richard A. Holley

Publication date: June 2015
, Volume 52
Author(s): Omaima M. Ahmed , Philipus Pangloli , Cheng-An Hwang , Svetlana Zivanovic , Tao Wu , Doris D'Souza , F.Ann Draughon

Publication date: June 2015
, Volume 48
Author(s): Declan J. Bolton

Vibrio cholerae is autochthonous to various aquatic niches and the etiological agent of the life-threatening diarrheal disease, cholera. The persistence of V. cholerae in natural habitats is a crucial factor in the epidemiology of cholera. In contrast to the well studied V. cholerae-chitin connection, scarce information is available about the factors employed by the bacteria for the interaction with collagens.