Effect of a Debaryomyces hansenii and Lactobacillus buchneri starter culture on Aspergillus westerdijkiae ochratoxin a production and growth during the manufacture of short seasoned dry-cured ham

Recently, specific dry-cured hams have started to be produced in San Daniele and Parma areas. The ingredients are similar to protected denomination of origin (PDO) produced in San Daniele or Parma areas, and include pork leg, coming from pigs bred in the Italian peninsula, salt and spices. However, these specific new products cannot be marked as a PDO, either San Daniele or Parma dry cured ham, because they are seasoned for 6 months, and the mark PDO is given only to products seasoned over 13 months. Consequently, these products are called short-seasoned dry-cured ham (SSDCH) and are not branded PDO. During their seasoning period, particularly from the first drying until the end of the seasoning period, many molds, including Eurotium spp. and Penicillium spp., can grow on the surface and work together with other molds and tissue enzymes to produce a unique aroma. Both of these strains typically predominate over other molds. However, molds producing ochratoxins, such as Aspergillus ochraceus and Penicillium nordicum, can simultaneously grow and produce ochratoxin A (OTA). Consequently, these dry-cured hams may represent a potential health risk for consumers. Recently, Aspergillus westerdijkiae has been isolated from SSDCHs, which could represent a potential problem for consumers. Therefore, the aim of this study was to inhibit A. westerdijkiae using Debaryomyces hansenii or Lactobacillus buchneri or a mix of both microorganisms. Six D. hansenii and six L. buchneri strains were tested in vitro for their ability to inhibit A. westerdijkiae. The strains D. hansenii (DIAL)1 and L. buchneri (Lb)4 demonstrated the highest inhibitory activity and were selected for in situ tests. The strains were inoculated or co-inoculated on fresh pork legs for SSDCH production with OTA-producing A. westerdijkiae prior to the first drying and seasoning. At the end of seasoning (six months), OTA was not detected in the SSDCH treated with both microorganisms and their combination. Because both strains did not adversely affect the SSDCH odor or flavor, the combination of these strains are proposed for use as starters to inhibit OTA-producing A. westerdijkiae

A Methodology for Assessing the Urban Supply of On-street Delivery Bays

The loading and unloading operations carried out by transport and logistics operators have a strong impact on city mobility if they are not performed correctly. If loading/unloading bays, i.e., delivery bays (DB), are not available for freight vehicle operations, operators may opt to double park or park on the sidewalk where there is no strong enforcement of these laws, with significant impact on congestion. This paper proposes a methodology for verifying and designing the number of delivery bays needed for freight vehicles for not interfere with cars or pedestrians. The methodology consists of two stages: in the first stage, an initial estimation is made using queueing theory. Subsequently, in the second stage, using such tentative scenario, in order to take into account the system stochasticity involving different entities, a discrete event simulation is performed to more realistically verify and upgrade (if necessary) the number of delivery bays to obtain the expected outcomes. The methodology was applied in the inner area of Santander (Spain). The study area was subdivided into 29 zones where the methodology was applied individually. The results indicated that none of these zones currently have an optimal number of delivery bays to satisfy demand. In some zones, there is an excess of delivery bays, although in most of them, there is a deficit which can cause significant impacts on traffic. The method proposed can be an effective tool to be used by city planners for improving freight operations in urban areas limiting the negative impacts produced in terms of internal and external costs

Ancient Roman bacterium against current issues: strain Aquil_B6, Paenisporosarcina quisquiliarum, or Psychrobacillus psychrodurans?

Thanks to the development of whole-genome sequencing technologies, nowadays researchers have access to rapid, effective, and precise resources for the genetic analysis of prokaryotes. The use of metrics that consider the entire DNA sequence, such as average nucleotide identity and digital DNA-DNA hybridization calculation, in fact, allows better results when compared to single-target gene analysis. However, it is increasingly important to employ reference databases containing correct information with high-quality sequences. The aim of this work is to taxonomically identify an unknown bacterial strain isolated from an ancient Roman amphora. However, it was necessary to resequence the genomes of the reference strains Paenisporosarcina quisquiliarum SK 55 and Psychrobacillus psychrodurans DSM 11713 to obtain correct and more reliable sequences than those available. It was, therefore, possible to uniquely identify the strain Aquil_B6 as Psy. psychrodurans. Also, to obtain further genetic information, given the low number of sequences available for this species, the genome of strain DSM 30747 was sequenced. Further characterization was made to identify the presence of possible genetic characteristic features such as CRISPR-Cas, prophages, resistance factors, and bacteriocins of this species, making a comparison between the available genomes of Paenisporosarcina quisquiliarum SK 55 and Psychrobacillus psychrodurans strains DSM 11713, DSM 30747, and Aquil_B6, to evaluate the impact of time on the evolution of the considered species

Lactic acid bacteria: Variability due to different pork breeds, breeding systems and fermented sausage production technology

Changes in the ecology of the various lactic acid bacteria (LAB) species, which are involved in traditional fermented sausages, were investigated in the light of the use of different breeds of pork, each of which was raised in two different environments and processed using two different technologies. The semi-quantitative molecular method was applied in order to understand how the different species alternate over time, as well as their concentration ratios. A significant increase in LAB over the first days of fermentation characterized the trials where the starter culture wasn\u2019t added (T), reaching values of 107\u2013108 cfu g 121. On the other hand, in the trials in which sausages were produced with starter addition, LAB counts had a less significant incremental jump from about 106 cfu g 121 (concentration of the inoculum) to 108 cfu g 121. Lactobacillus sakei and Lb. curvatus were detected as the prevalent population in all the observed fermentations. Pediococcus pentosaceus, Lb. casei, Leuconostoc mesenteroides, Lactococcus garviae, and Lb. graminis also appeared, but their concentration ratios varied depending on the diverse experimental settings. The results of cluster analysis showed that a plant- and breed-specific LAB ecology exists. In addition, it was also observed that the breeding system can influence the presence of certain LAB species

Listeria monocytogenes survey in cubed cooked ham packaged in modified atmosphere and bioprotective effect of selected lactic acid bacteria

The aim of this work was to study the presence of Listeria monocytogenes, as well as the potential activity of two bioprotective cultures (Lyocarni BOX-74 and Lyocarni BOX-57), versus a mix of three L. monocytogenes strains that were intentionally inoculated in cooked cubed ham, packaged in Modified Atmosphere Packaging and stored at different temperatures. The bioprotective cultures limit L. monocytogenes growth in cubed cooked ham stored either at 4\u25e6 C for 60 days and at 4\u25e6 C for 20 days and at 8\u25e6 C for 40 days. The inhibition at 8\u25e6 C is particularly useful for industrial cooked meat products, considering there are often thermal abuse conditions (8\u25e6 C) in the supermarkets. Both the starters can eliminate L. monocytogenes risk and maintain the products safe, despite the thermal abuse conditions. In addition, both culture starters grew without producing perceptible sensory variations in the samples, as demonstrated by the panel of the untrained tasters. The bioprotective LAB produced neither off-odours and off-flavours, nor white/viscous patinas, slime, discoloration or browning. Therefore, according to the obtained data, and despite the fact that cooked cubed ham did not show pH 64 4.4 or aw 64 0.92, or pH 64 5.0 and aw 64 0.94, as cited in the EC Regulation 2073/2005. It can be scientifically stated that cubes of cooked ham with the addition of bioprotective starters cultures do not constitute a favourable substrate for L. monocytogenes growth. Consequently, these products can easily fall into category 1.3 (ready-to-eat foods that are not favourable to L. monocytogenes growth, other than those for infants and for special medical purposes), in which a maximum concentration of L. monocytogenes of 100 CFU g 121 is allowed

Thermophilin 13: In Silico Analysis Provides New Insight in Genes Involved in Bacteriocin Production

Bacteriocins are a large family of ribosomally synthesised proteinaceous toxins that are produced by bacteria and archaea and have antimicrobial activity against closely related species to the producer strain. Antimicrobial proteinaceous compounds are associated with a wide range of applications, including as a pathogen inhibitor in food and medical use. Among the several lactic acid bacteria (LAB) commonly used in fresh and fermented food preservation, Streptococcus thermophilus is well known for its importance as a starter culture for yoghurt and cheese. Previous studies described the bacteriocin thermophilin 13 exclusively in S. thermophilus SFi13 and the genes encoding its production as an operon consisting of two genes (thmA and thmB). However, the majority of bacteriocins possess a complex production system, which involves several genes encoding dedicated proteins with relatively specific functions. Up to now, far too little attention has been paid to the genes involved in the synthesis, regulation and expression of thermophilin 13. The aim of the present study, using in silico gene mining, was to investigate the presence of a regulation system involved in thermophilin 13 production. Results revealed the dedicated putative bacteriocin gene cluster (PBGC), which shows high similarity with the class IIb bacteriocins genes. This newly revealed PBGC, which was also found within various strains of Streptococcus thermophilus, provides a new perspective and insights into understanding the mechanisms implicated in the production of thermophilin 13

Emulsion pcr (Epcr) as a tool to improve the power of dgge analysis for microbial population studies

To the authors\u2019 knowledge, this is the first report of the use of emulsion-Polymerase chain reaction (e-PCR) coupled with denaturing gradient gel electrophoresis (DGGE) analysis. In the present work the effectiveness of ePCR in improving the power of the DGGE technique for microbial population studies was tested. Our results indicated that ePCR results in uniform amplification of several DNA molecules, overcoming the major limitations of conventional PCR, such as preferential amplification and DNA concentration dependence. Moreover, ePCR-DGGE resulted in higher sensitivity when compared to conventional PCR-DGGE methods used for studying microbial populations in a complex matrix. In fact, compared to conventional PCR, the DGGE profiles of ePCR products permitted the detection of a higher number of the species that were present in the tested sample

Draft genome sequences of 14 Lacticaseibacillus spp. strains, representatives of a collection of 200 strains

Lactobacilli have a fundamental role in the food industry as starters and probiotics, therefore, requiring special attention concerning food safety. In this work, 14 strains selected accordingly to their genetic fingerprint and physiologic characteristics are presented as representatives of a collection of 200 strains

Geometrical and mechanical modeling of polymeric multi-ply yarns

This work aims to describe and predict the complex mechanical behavior of polymeric cords used as reinforcements in tires. Starting from the observed microstructure of the cords and from macroscopic experimental tests performed on single-ply yarns, a comprehensive geometric and mechanical model is developed. The real geometry of the cord is replaced by an equivalent three-dimensional continuum of a cylindrical shape, with a properly defined non-isotropic inelastic constitutive behavior. The three-dimensional viscoelastic and viscoplastic material model developed by the authors for rayon fibers is employed for this purpose. The actual directions of filaments inside the cord are computed by an analytical model, accounting for the twist in the yarns and in the filaments inside each yarn. Such directions, relevant to points of the cord cross-section, are then averaged along the pitch of the cord to obtain mean directions which represent the virtual reinforcement directions to be used in the equivalent cylindrical-shaped model. This analysis strategy is implemented in a finite element procedure. For rayon cords, the developed simulation tool (fed with appropriate parameters) gives numerical results that compare well with the corresponding experimental results. This approach could be effectively utilized in the analysis of cord-reinforced rubber composites