Research Publications (Food Safety)

Aims
Listeriosis is a frequent silage-associated disease in ruminants. The slugs Arion vulgaris are invaders in gardens, vegetable crops and meadows for silage production. Field and laboratory studies were conducted to clarify whether slugs could host Listeria monocytogenes and thereby constitute a threat to animal feed safety.

Publication date: 25 February 2015
, Volume 175, Issues 2–4
Author(s): Fernando L. Leite , Timothy A. Reinhardt , John P. Bannantine , Judith R. Stabel

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

Publication date: 2 April 2015
, Volume 198
Author(s): Tareq M. Osaili , Anas A. Al-Nabulsi , Ziad Jaradat , Reyad R. Shaker , Dalia Z. Alomari , Maher M. Al-Dabbas , Akram R. Alaboudi , Mohammad Q. Al-Natour , Richard A. Holley

Publication date: 2 April 2015
, Volume 198
Author(s): Kristin Weidemaier , Erin Carruthers , Adam Curry , Melody Kuroda , Eric Fallows , Joseph Thomas , Douglas Sherman , Mark Muldoon

Publication date: Available online 13 January 2015

Author(s): Sakshi Kohli , Yadvir Singh , Divya Tej Sowpati , Nasreen Z. Ehtesham , Ulrich Dobrindt , Jörg Hacker , Seyed E. Hasnain

Salmonella Typhimurium isolate D23580 represents a recently identified ST313 lineage of invasive non-Typhoidal Salmonellae (iNTS). One of the differences between this lineage and other non-iNTS S. Typhimurium isolates is the presence of prophage BTP1. This prophage encodes a gtrC gene, implicated in O-antigen modification. GtrCBTP1 is essential for maintaining O-antigen length in isolate D23580, since a gtrBTP1 mutant yields a short O-antigen.

Campylobacter jejuni is a leading cause of food-borne gastroenteritis in humans. It lives commensally in the gastrointestinal tract of animals, and tolerates variable conditions during transit/colonization of susceptible hosts. The C. jejuni CprRS two-component system contains an essential response regulator (CprR), and deletion of the cprS sensor kinase enhances biofilms. We sought to identify CprRS-regulated genes and better understand how the system affects survival.

Catalase enzymes detoxify H2O2 by the dismutation of H2O2 into O2 and H2O through the use of hemin cofactors. While the structure and biochemical properties of catalase enzymes have been well characterized over many decades of research, it remained unclear how catalases acquire hemin. We have previously reported that Cj1386 is essential for ensuring proper hemin content in Campylobacter jejuni catalase (KatA).

We evaluated the use of matrix-assisted laser desorption ionization–time of flight mass spectrometry (MS) for the identification of Vibrio cholerae. MS identified all 42 isolates of V. cholerae O1 and O139 and 7 of 9 non-O1/O139 isolates. MS correctly discriminated between all Aeromonas and V. cholerae isolates. Overall, MS performed as well as or better than biochemical methods.

The genus Yersinia is a large and diverse bacterial genus consisting of human-pathogenic species, a fish-pathogenic species, and a large number of environmental species. Recently, the phylogenetic and population structure of the entire genus was elucidated through the genome sequence data of 241 strains encompassing every known species in the genus.

An occurrence of Vibrio cholerae non-O1/O139 gastroenteritis in the U.S. Gulf Coast is reported here. Genomic analysis revealed that the isolate lacked known virulence factors associated with the clinical outcome of a V. cholerae infection but did contain putative genomic islands and other accessory virulence factors. Many of these factors are widespread among environmental strains of V. cholerae, suggesting that there might be additional virulence factors in non-O1/O139 V.

Yersinia enterocolitica and Yersinia pseudotuberculosis, the two Yersinia species that are enteropathogenic for humans, are distributed worldwide and frequently cause diarrhea in inhabitants of temperate and cold countries. Y. enterocolitica is a major cause of foodborne disease resulting from consumption of contaminated pork meat and is further associated with substantial economic cost.

Publication date: February 2015
, Volume 98, Issue 2
Author(s): Hossein Jamali , Mohammadjavad Paydar , Behrad Radmehr , Salmah Ismail

Many strains of lactic acid bacteria have been used for the production of probiotics. Some metabolites produced by lactic acid bacteria impair the motilities of pathogenic bacteria. Because bacterial motility is strongly associated with virulence, the metabolic activities of lactic acid bacteria are effective for suppressing bacterial infections. Here we show that lactose fermentation by Lactococcus lactis subsp. lactis inhibits the motility of Salmonella enterica serovar Typhimurium.

Natural competence, the ability of bacteria to take up exogenous DNA and incorporate it into their chromosomes, is in most bacteria a transient phenomenon under complex genetic and environmental control. In the Gram-negative bacteria Haemophilus influenzae and Vibrio cholerae the master regulator Sxy/TfoX controls competence development.

Bacterial type III secretion systems or injectisomes are multi protein complexes directly transporting bacterial effector proteins into eukaryotic host cells. To investigate the distribution of injectisomes in the bacterium and the influence of activation of the system on that distribution, we combined in vivo fluorescent imaging and high resolution in situ visualization of Yersinia enterocolitica injectisomes by cryo-electron tomography.

The bacterial phosphoenolpyruvate:sugar phosphotransferase system (PTS) consists of two general energy-coupling proteins (enzyme I and HPr) and several sugar-specific enzyme IIs. Although, in addition to the phosphorylation-coupled transport of sugars, various regulatory roles of PTS components have been identified in Escherichia coli, much less is known about the PTS in the opportunistic human pathogen Vibrio vulnificus.

Publication date: February 2015
, Volume 100
Author(s): I. Leceta , S. Molinaro , P. Guerrero , J.P. Kerry , K. de la Caba

Staphylococcal enterotoxins (SEs) are powerful superantigenic toxins produced by Staphylococcus aureus (S. aureus). They can cause food poisoning and toxic shock. However, their impact on bovine mammary epithelial cells (bMECs) is still unknown. In this study, the distribution of SE genes was evaluated in 116 S. aureus isolates from bovine mastitis, and the most prevalent genes were seh (36.2%), followed by sei (12.1%), seg (11.2%), ser (4.3%), sec (3.4%), sea (2.6%) and sed (1.7%).

Publication date: 1 June 2015
, Volume 176
Author(s): Lili Yu , Yang Zhang , Chenyi Hu , Hui Wu , Yayun Yang , Chusen Huang , Nengqin Jia

Publication date: May 2015
, Volume 51
Author(s): Daofeng Liu , Yanmei Huang , Shuying Wang , Kun Liu , Minghui Chen , Yonghua Xiong , Wanchun Yang , Weihua Lai

Publication date: June 2015
, Volume 52
Author(s): Gabriela Castillo , Katia Spinella , Alexandra Poturnayová , Maja Šnejdárková , Lucia Mosiello , Tibor Hianik

Aim
This study evaluated the binding capacity of aflatoxin B1 (AFB1) by two Enterococcus faecium strains (MF4 and GJ40) isolated from faeces from healthy dogs.

Materials and Methods
The binding assay was performed using 50 and 100 ppb of AFB1 analysing the effects of the viability, incubation time and pH on AFB1 binding. Binding stability was determined by washing three times the bacteria-AFB1 complexes with phosphate buffer saline.

Ochratoxin A (OTA) is nephrotoxic, hepatotoxic, immunotoxic, neurotoxic, reprotoxic, teratogenic, and carcinogenic (group 2B), being characterized by species and sex differences in sensitivity. Despite the fact that OTA is in some aspects a controversial topic, OTA is the most powerful renal carcinogen. The aim of this study was to make a small survey concerning OTA content in black tea, fruit tea, and ground roasted coffee, and to assess OTA transfer into beverages.