Research Publications (Food Safety)

Publication date: 15 May 2015
, Volume 177, Issues 1–2
Author(s): Christiane Cuny , Mohamed Abdelbary , Franziska Layer , Guido Werner , Wolfgang Witte

Escherichia coli is one of the foodborne pathogens associated with several cases of human sickness. Duck meat is an excellent source of animal-derived high quality proteins. This study was undertaken to investigate the possible transmission of diarrheagenic E. coli from consumption of duck meat and giblets. Additionally, expression of some virulence-associated genes in the isolated E. coli serotypes was examined using polymerase chain reaction.

Biofilm of Cronobacter sakazakii on food contact surfaces is the important source of persistent contamination in powdered infant formula. This study aimed to assess the effects of Ca2+ and Mg2+ on biofilm formation. Results indicated that the biofilm-forming ability was strain specific and divalent cation concentrations dependent. Most of C. sakazakii formed the highest amount of biomass at 1.50% MgCl2 (17 strains, 74%) and 0.25% CaCl2 (10 strains, 43.4%).

Shiga toxin-producing Escherichia coli (STEC) produce shiga toxins (Stxs) that can cause human disease and death. The contamination of food products with STEC represents a food safety problem that necessitates rapid and effective detection strategies to mitigate risk.

In order to elucidate the main predictors of Vibrio cholerae dynamics and to estimate the risk of V.cholerae related diseases, a recently developed direct detection approach based on FISH and solid phase cytometry (CARD-FISH/SPC) was applied in comparison to cultivation for water samples from the lake Neusiedler See, Austria and three shallow alkaline lakes over a period of 20 months. V.cholerae attached to crustacean zooplankton was quantified via FISH and epifluorescence microscopy.

Publication date: October 2015
, Volume 56
Author(s): Carlos Alonso-Calleja , Emilia Guerrero-Ramos , Alicia Alonso-Hernando , Rosa Capita

Foodborne Pathogens and Disease Apr 2015, Vol. 12, No. 4: 323-326.

Koseki, Shigenobu et al. Under osmotic stress, bacterial cells uptake compatible solutes such as glycine-betaine to maintain homeostasis. It is unknown whether incompatible solutes exist that are similar in structure to compatible solutes but have adverse physiological effects on bacterial physiology. The objective of this study was to evaluate solute incompatibility of various amino acids against bacterial growth.

Donado-Godoy, Pilar et al. Salmonella Paratyphi B dT+ variant (also termed Salmonella Java) and Salmonella Heidelberg are pathogens of public health importance that are frequently isolated from poultry.

Reyes-Rodríguez, Nydia E. et al. Meat of bovine origin is one of the major vehicles in the transmission of verotoxigenic Escherichia coli (VTEC) to human consumers. This pathogen can produce serious human illness, including bloody diarrhea and hemolytic uremic syndrome. The aim of the current study was to characterize E. coli isolates (mainly VTEC strains) belonging to several serotypes in samples from cattle carcasses and feces of three municipal slaughter plants from Mexico State.

Casco, G. et al.

Al-Qadiri, Hamzah et al. This study investigated the growth and survival of three foodborne pathogens (Clostridium perfringens, Campylobacter jejuni, and Listeria monocytogenes) in beef (7% fat) and nutrient broth under different oxygen levels. Samples were tested under anoxic (<0.5%), microoxic (6 to 8%), and oxic (20%) conditions during storage at 7°C for 14 days and at 22°C for 5 days. Two initial inoculum concentrations were used (1 and 2 log CFU per g of beef or per ml of broth).

Jensen, Dane A. et al. Hand washing is recognized as a crucial step in preventing foodborne disease transmission by mitigating cross-contamination among hands, surfaces, and foods. This research was undertaken to establish the importance of several keys factors (soap, soil, time, and drying method) in reducing microorganisms during hand washing.

Livezey, Kristin W. et al. Escherichia coli O157:H7 and six serovars (O26, O103, O121, O111, O145, and O45) are frequently implicated in severe clinical illness worldwide. Standard testing methods using stx, eae, and O serogroup–specific gene sequences for detecting the top six non-O157 STEC bear the disadvantage that these genes may reside, independently, in different nonpathogenic organisms, leading to false-positive results.

Eady, Matthew et al. This study was designed to evaluate hyperspectral microscope images for early and rapid detection of Salmonella serotypes Enteritidis, Heidelberg, Infantis, Kentucky, and Typhimurium at incubation times of 6, 8, 10, 12, and 24 h. Images were collected by an acousto-optical tunable filter hyperspectral microscope imaging system with a metal halide light source measuring 89 contiguous wavelengths every 4 nm between 450 and 800 nm.

Keller, Susanne E. et al. The survival of Salmonella on dried chamomile flowers, peppermint leaves, and green tea leaves stored under different conditions was examined. Survival and growth of Salmonella was also assessed after subsequent brewing using dried inoculated teas. A Salmonella enterica serovar cocktail was inoculated onto different dried tea leaves or flowers to give starting populations of approximately 10 log CFU/g.

Delbeke, Stefanie et al. The survival of Salmonella and Escherichia coli O157:H7 on strawberries, basil leaves, and other leafy greens (spinach leaves, lamb and butterhead lettuce leaves, baby leaves, and fresh-cut iceberg lettuce) was assessed at cold (<7°C) and ambient temperatures. All commodities were spot inoculated with E. coli O157:H7 or Salmonella to obtain an initial inoculum of 5 to 6 log and 4 to 5 log CFU/g for strawberries and leafy greens, respectively.

du Plessis, Erika M. et al. The potential transfer of human pathogenic bacteria present in irrigation water onto fresh produce was investigated, because surface water sources used for irrigation purposes in South Africa have increasingly been reported to be contaminated with enteric bacterial pathogens.

Williams, K. J. et al. A longitudinal study was conducted to assess the methods available for detection of Escherichia coli O157 and to investigate the prevalence and occurrence of long-term shedding and super shedding in a cohort of Australian dairy heifers. Samples were obtained at approximately weekly intervals from heifers at pasture under normal management systems.

Publication date: October 2015
, Volume 56
Author(s): María Ruiz-Rico , Cristina Fuentes , Édgar Pérez-Esteve , Ana I. Jiménez-Belenguer , Amparo Quiles , María D. Marcos , Ramón Martínez-Máñez , José M. Barat

Publication date: 2 July 2015
, Volume 204
Author(s): Yun Jiang , Shuang Yin , Edward G. Dudley , Catherine N. Cutter

The microaerophilic food-borne pathogen Campylobacter jejuni uses complex cytochrome-rich respiratory chains for growth and host colonization. Cytochrome c biogenesis requires haem ligation to reduced apocytochrome cysteines, catalysed by the cytochrome c synthase, CcsBA. While ccsBA could not be deleted, we showed that the thiol reductase DsbD and the CcsX homologue Cj1207 are involved in, but not essential for, cytochromes c biogenesis.

The biological roles of low molecular weight penicillin-binding proteins (LMW PBP) have been difficult to discern in Gram-negative organisms. In E. coli, mutants lacking these proteins often have no phenotype, and cells lacking all 7 LMW PBPs remain viable. In contrast, we report here that Vibrio cholerae lacking DacA-1, a PBP5 homolog, displays slow growth, aberrant morphology, and altered peptidoglycan (PG) homeostasis in LB medium, as well as a profound plating defect.

Tetrodotoxin (TTX) is a potent neurotoxin found in the tissues of many taxonomically diverse organisms. Its origin has been the topic of much debate, with suggestions including endogenous production, acquisition through diet, and symbiotic bacterial synthesis. Bacterial production of TTX has been reported in isolates from marine biota, but at lower than expected concentrations. In this study, 102 strains were isolated from Pleurobranchaea maculata (Opisthobranchia) and Stylochoplana sp.

Sergio Sánchez, María Teresa Llorente, María Aurora Echeita, Silvia Herrera-León