172 research outputs found
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
Assessment of lipid oxidation and microbial decontamination of sardine (Sardina pilchardus) fillets processed by plasma-activated water (PAW)
Plasma activated water (PAW) is emerging as a mild and environmentally friendly technology for microbial and chemical decontamination of food. The aim of this work was to evaluate the degree of oxidation of lipids of sardine tissue treated by PAW generated with a pulsed corona discharge. The effect of PAW on the natural microflora of the fish was also evaluated. Under the adopted experimental conditions, PAW was able to reduce the number of mesophilic aerobes and Pseudomonas spp. by 0.22 and 0.20 log units, respectively, but no increase in shelf life was observed at chilling temperatures compared to water washing. A loss of polyunsaturated fatty acids (PUFAs) and an increase in volatile oxidation products derived from the cleavage of PUFA hydroperoxides were observed at the longest treatment duration. Twelve cholesterol oxidation products (COPs) were identified in sardine lipids, but no significant differences in total COPs content were observed between PAW processed and control samples. Free radical mediated oxidation pathways led to the most abundant COPs, but a significant contribution of non-radical pathways was also observed. Further studies are needed to better understand the low efficiency of PAW in microbial decontamination of proteinaceous materials
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
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