Research Publications (Food Safety)

The study involved 75 autochthonous lactic acid bacteria (LAB) obtained from Valtellina Casera Protected Designation of Origin cheese and provides data on their antibiotic resistance (AR), antimicrobial activity and safety aspects. High biodiversity was revealed, assigning the isolates to 16 species. In the curd Streptococcus thermophilus was predominant, while Enterococcus and the Lactobacillus casei group prevailed in ripened cheese.

In this study, adaptive neuro-fuzzy inference system (ANFIS) and genetic algorithm–artificial neural network (GA-ANN) models were used to predict inactivation of Salmonella enteritidis by ultrasound. The effect of amplitude levels, duty cycles and irradiation time of ultrasound on inactivation of S. enteritidis was investigated.

Publication date: Available online 23 January 2015

Author(s): A. Bousquet , S. Henquet , F. Compain , N. Genel , G. Arlet , D. Decré

Publication date: May 2015
, Volume 103
Author(s): M. Mataragas , A. Bellio , F. Rovetto , S. Astegiano , L. Decastelli , L. Cocolin

Vibrio vulnificus is a Gram-negative pathogen found in coastal and estuarine waters worldwide that can cause life threatening diseases. Characterization of the vcg (virulence correlated gene) or 16S rRNA alleles is used to distinguish virulent (clinical (C)-type) from presumably avirulent (environmental (E)-type) strains. However, some studies reported significant numbers of clinical strains belonging to the E-type.

Polymeric nanocomposites embedded with nontoxic antimicrobial agents have recently gained potential industrial significancemainly for their applicability to preserve food quality and ensure safety. In this study, a poly(butylene adipate-co-terephthalate) (PBAT)/organoclay (CMMT) based nanocomposite film doped with sodium benzoate (SB) as antimicrobial agent was prepared by a solution mixing process.

January Online CoverMaize kernels, with inset of hyperspectral image showing regions of interest, from “Feasibility of Detecting Aflatoxin B1 on Inoculated Maize Kernels Surface using Vis/NIR Hyperspectral Imaging” by Wei Wang, Gerald W. Heitschmidt, William R. Windham, Peggy Feldner, Xinzhi Ni, and Xuan Chu; p. M117.

Vibrio vulnificus contains two coproporphyrinogen III oxidases (CPOs): O2-dependent HemF and O2-independent HemN. The growth of the hemF mutant HF1 was similar to wild-type cells at pH 7.5 under 2% O2 conditions where HemN was active and had a half-life of 64 min. However, HF1 did not grow when the medium pH decreased to pH 5.0, where oxidative stress affects endogenous S-adenosylmethionine (SAM) levels.

Matthew Darby, Corinna Schnoeller, Alykhan Vira, Fiona Culley, Saeeda Bobat, Erin Logan, Frank Kirstein, Jürgen Wess, Adam F. Cunningham, Frank Brombacher, Murray E. Selkirk, William G. C. Horsnell

The majority of foodborne illness outbreaks can be linked to cross-contamination events through contact with contaminated surfaces. Consequently, there is a sustained interest in developing antimicrobial coatings such as silver zeolite to reduce contamination levels. In this study, we examined the efficacy of silver zeolite for preventing biofilm formation by common foodborne pathogens such as Listeria innocua Seeliger and Escherichia coli O157:H7.

Publication date: July 2015
, Volume 53
Author(s): Vicente M. Gómez-López , María I. Gil , Ana Allende , Bert Vanhee , María V. Selma

The antimicrobial effect of spice-based marinades against Campylobacter jejuni on inoculated fresh broiler wings was investigatedExperiments were carried out with 1 strain of C. jejuni and 6 marinades. Four experimental marinades were composed for the study and contained spices (thyme, rosemary, basil, marjoram, and so on) and different combination of bioactive compounds.

Morcela de ArrozMA) is a ready-to-eat blood and rice cooked sausage produced with pork, blood, rice, and seasonings, stuffed in natural casing and cooked above 90 °C/30 min. It is commercialized whole, not packed, with a restricted shelf life (1 wk/0 to 5 °C). The objective of this work was to establish sliced MA shelf life considering both the behavior of L.

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.