Search Results (5)

Ecological and safe packaging solutions arise as pivotal points in the development of an integrated system for sustainable meat production. The aim of this study was to assess the effect of a combined chitosan (Ch) + green tea extract (GTE) + essential oil (thyme oil, TO; flaxseed oil, FO; or oregano oil, OO) coating on the safety and quality of vacuum-packaged beef during storage at 4 °C. An optimized bio-based coating formulation was selected (2% Ch + 2% GTE + 0.1% FO) to be applied to three fresh beef cuts (shoulder, Sh; knuckle, Kn; Striploin, St) based on its pH (5.8 ± 0.1), contact angle (22.3 ± 0.4°) and rheological parameters (viscosity = 0.05 Pa.s at shear rate > 20 s⁻¹). Shelf-life analysis showed that the Ch–GTE–FO coating delayed lipid oxidation and reduced total viable counts (TVC) and Enterobacteriaceae growth compared with uncoated beef samples over five days. In addition, Ch–GTE–FO coating decreased total color changes of beef samples (e.g., ∆E* = 9.84 and 3.94, for non-coated and coated Kn samples, respectively) for up to five days. The original textural parameters (hardness, adhesiveness and springiness) of beef cuts were maintained during storage when Ch–GTE–FO coating was applied. Based on the physicochemical and microbial characterization results, the combination of the Ch–GTE–FO coating developed was effective in preserving the quality of fresh beef cuts during refrigerated storage along with vacuum packaging. Full article

The Gram-negative bacterial genus Xanthomonas includes numerous infra-specific taxa known as pathovars, which are defined primarily on host range and disease symptoms. With the advent of molecular sequence data, many pathovars have been transferred from X. campestris into other Xanthomonas species to better harmonise taxonomy and phylogeny. We performed whole-genome shotgun sequencing on pathotype strains of the following X. campestris pathovars: blepharidis, carissae, clerodendri, convolvuli, coriandri, daturae, euphorbiae, fici, heliotropii, ionidii, lawsoniae, mirabilis, obscurae, paulliniae, pennamericanum, spermacoces, uppalii, vernoniae, viegasii and zingibericola. These genomes showed more than 98% average nucleotide identity with the type-strain of X. euvesicatoria and less than 88% with the type-strain of X. campestris. We propose the transfer of these pathovars into X. euvesicatoria and present an emended species description for X. euvesicatoria. Full article

Bacteria in the genus Xanthomonas infect a wide range of crops and wild plants, with most species responsible for plant diseases that have a global economic and environmental impact on the seed, plant, and food trade. Infections by Xanthomonas spp. cause a wide variety of non-specific symptoms, making their identification difficult. The coexistence of phylogenetically close strains, but drastically different in their phenotype, poses an added challenge to diagnosis. Data on future climate change scenarios predict an increase in the severity of epidemics and a geographical expansion of pathogens, increasing pressure on plant health services. In this context, the effectiveness of integrated disease management strategies strongly depends on the availability of rapid, sensitive, and specific diagnostic methods. The accumulation of genomic information in recent years has facilitated the identification of new DNA markers, a cornerstone for the development of more sensitive and specific methods. Nevertheless, the challenges that the taxonomic complexity of this genus represents in terms of diagnosis together with the fact that within the same bacterial species, groups of strains may interact with distinct host species demonstrate that there is still a long way to go. In this review, we describe and discuss the current molecular-based methods for the diagnosis and detection of regulated Xanthomonas, taxonomic and diversity studies in Xanthomonas and genomic approaches for molecular diagnosis. Full article

Functional films based on black chia (Salvia hispanica L.) seed mucilage (BCm) containing Rhus microphylla (Rm) fruit phenolic extract were built and characterized. A hydro-alcohol extract (HAE) of Rm was incorporated as the bioactive agent due to its noteworthy phenolic profile, and good antioxidant and antifungal activities. The effects of the BCm concentration (0.2% and 0.4%, w/v), HAE incorporation, and their interaction with glycerol (1.0%, w/v) and calcium chloride (0.05%, w/v) on the films’ physicochemical properties were evaluated. The filmogenic solutions successfully fitted to the Herschel–Bulkley model (R² < 0.999), exhibiting a pseudoplastic and shear thinning character, typical of polymer solutions. Interestingly, their rheological properties were not (p > 0.05) changed by the HAE addition, but their surface tension was enhanced (p < 0.05), which could favor their coating ability. The polyanionic nature of the systems (zeta potential-Zp values from −26.9 to −33.3 mV) allowed them to interact with Ca²⁺ cations, thus forming stable and resistant films. All the films showed low water solubility (15.0% to 22.3%) and high permeability (3.7 to 4.0 × 10⁻¹⁰ g m⁻¹ s⁻¹ Pa⁻¹), as well as high biodegradability (moisture content from 66.0% to 80.9%); although the moisture content was reduced (p < 0.05) with HAE addition. The combination of higher BCm ratio and HAE addition (BCm0.4+Rm) led to a more resistant, thick, opaque, and dark film compared with the others obtained. This study reveals the BCm-based films’ potential, highlighting those with HAE, representing a novel alternative to improve the quality of food products. Full article

Black rot, caused by Xanthomonas campestris pv. campestris (Xcc), is a seed borne disease of Brassicaceae. Eleven pathogenic races have been identified based on the phenotype interaction pattern of differential brassica cultivars inoculated with different strains. Race 1 and 4 are the two most frequent races found in Brassica oleracea crops. In this study, a PCR molecular diagnostic tool was developed for the identification of Xcc races 1 and 4 of this pathogen. Whole genomic sequences of races 1, 3, 4 and 9 and sequences of three other Xanthomonas pathovars/species (X. campestris pv. incanae (Xci), X. campestris pv. raphani (Xcr) and X. euvesicatoria (Xev) were aligned to identify variable regions among races. To develop specific markers for races 1 and 4, primers were developed from a region where sequences were dissimilar in other races. Sequence-characterized amplified regions (SCAR) and insertion or deletion of bases (InDel) were used to develop each specific set of primers. The specificity of the selected primers was confirmed by PCR tests using genomic DNA of seven different Xcc races, two strains of X. campestris pathovars and other species of bacteria. Bacterial samples of the races 1 and 4 isolates were collected from artificially inoculated cabbage leaves to conduct bio-PCR. Bio-PCR successfully detected the two Xcc isolates. By using our race-specific markers, a potential race 1 strain from the existing Korean Xcc collection was identified. The Xcc race 1 and 4-specific markers developed in this study are novel and can potentially be used for rapid detection of Xcc races through PCR. Full article