Prevalence and risk factors for thermotolerant species of Campylobacter in poultry meat at retail in Europe

Abstract The thermotolerant species Campylobacter jejuni, Campylobacter coli, Campylobacter lari and Campylobacter upsaliensis are the causative agents of the human illness called campylobacteriosis. This infection represents a threat for the health of consumers in Europe. It is well known that poultry meat is an important food vehicle of Campylobacter infection. As emerged from the reported scientific literature published between 2006 and 2016, poultry meat sold at retail level in Europe represents an important source of the pathogen. The contamination level of poultry meat sold at retail can vary depending on pre- and post-harvest factors. Among the pre-harvest measures, strict biosecurity practices must be guaranteed; moreover, among post-harvest control measures scalding, chilling and removal of faecal residues can reduce the contamination level of Campylobacter. An additional issue is represented by increasing proportion of Campylobacter isolates resistant to tetracyclines, ciprofloxacin, and nalidixic acid, thus feeding a serious concern on the effectiveness of antibiotic treatment for human campylobacteriosis in a near future

Fermentation of Microalgal Biomass for Innovative Food Production

Fermentation is an ancient method used worldwide to process and preserve food while enhancing its nutraceutical profile. Alga‐based fermented products have recently been developed and tested due to growing interest in healthy sustainable diets, which demands the development of innovative practices in food production, operating for both human health and Earth sustainability. Algae, particularly microalgae such as Arthrospira platensis, Chlorella vulgaris, and Dunaliella salina, are already cultivated as sources of food due to their valuable compounds, including proteins, pigments, lipids, carotenoids, polyunsaturated fatty acids, steroids, and vitamins. Due to their nutritional composition, functional diversity, and flexible metabolism, microalgae represent good fermentation substrates for lactic acid bacteria (LAB) and yeasts. This review presents an overview of the scientific studies on microalga fermentation underlining microalgae’s properties and health benefits coupled with the advantages of LAB and yeast fermentation. The potential applications of and future perspectives on such functional foods are discussed

Innovative Fermented Beverages Made with Red Rice, Barley, and Buckwheat

The increase in food intolerances, allergies, and food-based lifestyle choices has dramatically increased the consumer demand for healthy foods characterized by pleasant sensory traits. In such a context, innovative cereal-based beverages are characterized by high nutritional value, pleasant palatability, and potential healthy properties. In the present study, a pool of 23 lactic acid bacteria strains was preliminary assayed as monocultures for the fermentation of three ad hoc formulated cereal- (red rice and barley) and pseudocereal (buckwheat) -based substrates. Eight strains with the best performance in terms of acidification rate were selected for the formulation of three multiple strain cultures to be further exploited for the manufacture of laboratory-scale prototypes of fermented beverages. The compositional and microbiological features of the three experimental beverages highlighted their high biological value for further exploitation

Effect of temperature and relative humidity on algae biofouling on different fired brick surfaces

Abstract The purpose of this study was to evaluate the effect of environmental temperature and relative humidity on algae biofouling that often occurs on porous and rough fired brick surfaces. Brick samples were chosen since their common use on building facades. Accelerated growth tests were performed under different relative humidities and different temperatures. Results showed the effects of different temperature conditions in terms of algae growth delay and reduction of the covered area. All the relative humidity conditions tested substantially showed no growth from an engineering standpoint. The modified Avrami's law succeeded in modelling the biofouling under the different environmental conditions

Exploitation of Tenebrio molitor larvae as biological factories for human probiotics, an exploratory study

The exploitation of yellow mealworm (Tenebrio molitor) larvae for the bioaugmentation of probiotic Bacillus clausii strains was evaluated during a 7-day rearing period. qPCR was applied to evaluate the persistence and growth of B. clausii in the rearing substrate and larvae (washed and non-washed). Moreover, the effect of freeze-drying of larvae on B. clausii viability was evaluated. The results demonstrated the suitability of yellow mealworm as biological factories for the multiplication of B. clausii through a simple and inexpensive procedure, in view of the further application of larvae as foods and food ingredients. In more detail, an increase in the load of B. clausii was observed during the 7-day rearing of larvae fed wheat middlings spiked with 1 Log cells g−1. Further research is needed to evaluate the most suitable technologies and processing parameters for obtaining yellow mealworm-based ingredients with a stable and active population of probiotic B. clausii

Lactic acid bacteria and yeasts from wheat sourdoughs of the Marche region

The need for a greater diversification of baked products has given rise to the on-going search for yeast and lactic acid bacteria (LAB) strains with optimal baking potential. Thirty-six yeasts and 118 LAB, isolated from nine type I sourdoughs that were sampled in bakeries located in the Marche region (central Italy), were molecularly and phenotypically characterized. The polyphasic approach used revealed the biodiversity of the microbial communities investigated and two yeasts and ten LAB cultures with the potential to be used in sourdough bread-making processes were identified

Microbial dynamics in rearing trials of Hermetia illucens larvae fed coffee silverskin and microalgae

In the present study, Hermetia illucens larvae were reared on a main rearing substrate composed of a coffee roasting byproduct (coffee silverskin, Cs) enriched with microalgae (Schizochytrium limacinum or Isochrysis galbana) at various substitution levels. The microbial diversity of the rearing substrates, larvae, and frass (excrement from the larvae mixed with the substrate residue) were studied by the combination of microbial culturing on various growth media and metataxonomic analysis (Illumina sequencing). High counts of total mesophilic aerobes, bacterial spores, presumptive lactic acid bacteria, coagulase-positive cocci, and eumycetes were detected. Enterobacteriaceae counts were low in the rearing diets, whereas higher counts of this microbial family were observed in the larvae and frass. The microbiota of the rearing substrates was characterized by the presence of lactic acid bacteria, including the genera Lactobacillus, Leuconostoc and Weissella. The microbiota of the H. illucens larvae fed Cs was characterized by the dominance of Paenibacillus. H. illucens fed diets containing I. galbana were characterized by the presence of Enterococcus, Lysinibacillus, Morganella, and Paenibacillus, depending on the algae inclusion level, while H. illucens fed diets containing S. limacinum were characterized by high relative abundances of Brevundimonas, Enterococcus, Paracoccus, and Paenibacillus, depending on the algae inclusion level. Brevundimonas and Alcaligenes dominated in the frass from larvae fed I. galbana; the predominance of Brevundimonas was also observed in the frass from larvae fed Schyzochitrium-enriched diets. Based on the results of the present study, an effect of algae nutrient bioactive substances (e.g. polysaccharides, high-unsaturated fatty acids, taurine, carotenoids) on the relative abundance of some of the bacterial taxa detected in larvae may be hypothesized, thus opening new intriguing perspectives for the control of the entomopathogenic species and foodborne human pathogens potentially occurring in edible insects. Further studies are needed to support this hypothesis. Finally, new information on the microbial diversity occurring in insect frass was also obtained

Study of the bacterial diversity of foods: PCR-DGGE versus LH-PCR

The present study compared two culture-independent methods, polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE) and length-heterogeneity polymerase chain reaction (LH-PCR), for their ability to reveal food bacterial microbiota. Total microbial DNA and RNA were extracted directly from fourteen fermented and unfermented foods, and domain A of the variable regions V1 and V2 of the 16S rRNA gene was analyzed through LH-PCR and PCR-DGGE. Finally, the outline of these analyses was compared with bacterial viable counts obtained after bacterial growth on suitable selective media. For the majority of the samples, RNA-based PCR-DGGE revealed species that the DNA-based PCR-DGGE was not able to highlight. When analyzing either DNA or RNA, LH-PCR identified several lactic acid bacteria (LAB) and coagulase negative cocci (CCN) species that were not identified by PCR-DGGE. This phenomenon was particularly evident in food samples with viable loads b 5.0 Log cfu g−1 . Furthermore, LH-PCR was able to detect a higher number of peaks in the analyzed food matrices relative to species identified by PCR-DGGE. In light of these findings, it may be suggested that LH-PCR shows greater sensitivity than PCR-DGGE. However, PCR-DGGE detected some other species (LAB included) that were not detected by LH-PCR. Therefore, certain LH-PCR peaks not attributed to known species within the LH-PCR database could be solved by comparing them with species identified by PCR-DGGE. Overall, this study also showed that LH-PCR is a promising method for use in the food microbiology field, indicating the necessity to expand the LH-PCR database, which is based, up to now, mainly on LAB isolates from dairy produc

The Microbial Diversity of Non-Korean Kimchi as Revealed by Viable Counting and Metataxonomic Sequencing

Kimchi is recognized worldwide as the flagship food of Korea. To date, most of the currently available microbiological studies on kimchi deal with Korean manufactures. Moreover, there is a lack of knowledge on the occurrence of eumycetes in kimchi. Given these premises, the present study was aimed at investigating the bacterial and fungal dynamics occurring during the natural fermentation of an artisan non-Korean kimchi manufacture. Lactic acid bacteria were dominant, while Enterobacteriaceae, Pseudomonadaceae, and yeasts progressively decreased during fermentation. Erwinia spp., Pseudomonas veronii, Pseudomonas viridiflava, Rahnella aquatilis, and Sphingomonas spp. were detected during the first 15 days of fermentation, whereas the last fermentation phase was dominated by Leuconostoc kimchi, together withWeissella soli. For the mycobiota at the beginning of the fermentation process, Rhizoplaca and Pichia orientalis were the dominant Operational Taxonomic Units (OTUs) in batch 1, whereas in batch 2 Protomyces inundatus prevailed. In the last stage of fermentation, Saccharomyces cerevisiae, Candida sake, Penicillium, and Malassezia were the most abundant taxa in both analyzed batches. The knowledge gained in the present study represents a step forward in the description of the microbial dynamics of kimchi produced outside the region of origin using local ingredients. It will also serve as a starting point for further isolation of kimchi-adapted microorganisms to be assayed as potential starters for the manufacturing of novel vegetable preserves with high quality and functional traits