Process Development for the Spray-Drying of Probiotic Bacteria and Evaluation of the Product Quality.

Probiotics and prebiotics are of great interest to the food and pharmaceutical industries due to their health benefits. Probiotics are live bacteria that can confer beneficial effects on human and animal wellbeing, while prebiotics are types of nutrients that feed the beneficial gut bacteria. Powder probiotics have gained popularity due to the ease and practicality of their ingestion and incorporation into the diet as a food supplement. However, the drying process interferes with cell viability since high temperatures inactivate probiotic bacteria. In this context, this study aimed to present all the steps involved in the production and physicochemical characterization of a spray-dried probiotic and evaluate the influence of the protectants (simulated skim milk and inulin:maltodextrin association) and drying temperatures in increasing the powder yield and cell viability. The results showed that the simulated skim milk promoted higher probiotic viability at 80 °C. With this protectant, the probiotic viability, moisture content, and water activity (Aw) reduce as long as the inlet temperature increases. The probiotics' viability decreases conversely with the drying temperature. At temperatures close to 120 °C, the dried probiotic showed viability around 90%, a moisture content of 4.6% w/w, and an Aw of 0.26; values adequate to guarantee product stability. In this context, spray-drying temperatures above 120 °C are required to ensure the microbial cells' viability and shelf-life in the powdered preparation and survival during food processing and storage.

Phytochemistry and antimicrobial activity of Campomanesia adamantium

ABSTRACT Campomanesia adamantium (Cambess.) O. Berg., Myrtaceae, is a plant popularly used for its anti-inflammatory, anti-diarrhoeal and urinary antiseptic activities. The aims of this study were to obtain the crude ethanolic extract and the hexane, dichloromethane, ethyl acetate, aqueous and concentrated aqueous tannin fractions from C. adamantium leaves, perform biomonitored fractionation to isolate and identify chemical compounds, study the chemical composition of the volatile oils of the leaves and flowers and test the antimicrobial activity of the ethanolic extract, fractions, isolated substances and volatile oils. Phytochemical screening and chromatographic and spectrometric techniques were used. Volatile oils were isolated by hydrodistillation in a Clevenger apparatus and analyzed by gas chromatography/mass spectrometry. The antimicrobial activity was tested by a broth microdilution test. The component stictane-3,22-diol was isolated and identified from the hexane fraction, while valoneic and gallic acid were isolated and identified from the concentrated aqueous tannin fraction. The major constituents of the volatile oils of the leaves were verbenene (13.91%), β-funebrene (12.05%) and limonene (10.32%), while those of the volatile oils of the flowers were sabinene (20.45%), limonene (19.33%), α-thujene (8.86%) and methyl salicylate (8.66%). Antibacterial activity was verified for the hexane fraction, while antifungal activity was observed for the aqueous fraction and concentrated aqueous tannin fraction and for vanoleic acid. These results may justify the popular use of C. adamantium.

Staphylococcus aureus in Some Brazilian Dairy Industries: Changes of Contamination and Diversity.

Staphylococcus aureus, a major food-poisoning pathogen, is a common contaminant in dairy industries worldwide, including in Brazil. We determined the occurrence of S. aureus in five dairies in Brazil over 8 months. Of 421 samples, 31 (7.4%) were positive for S. aureus and prevalence varied from 0 to 63.3% between dairies. Sixty-six isolates from the 31 samples were typed by Multi-Locus Sequence Typing to determine if these isolates were persistent or continuously reintroduced. Seven known sequence types (STs), ST1, ST5, ST30, ST97, ST126, ST188 and ST398, and four new ST were identified, ST3531, ST3540, ST3562 and ST3534. Clonal complex (CC) 1 (including the four new ST), known as an epidemic clone, was the dominant CC. However, there were no indications of persistence of particular ST. The resistance toward 11 antibiotic compounds was assessed. Twelve profiles were generated with 75.8% of strains being sensitive to all antibiotic classes and no Methicillin-resistant S. aureus (MRSA) strains were found. The enterotoxin-encoding genes involved in food-poisoning, e.g., sea, sed, see, and seg were targeted by PCR. The two toxin-encoding genes, sed and see, were not detected. Only three strains (4.5%) harbored seg and two of these also harbored sea. Despite the isolates being Methicillin-sensitive S. aureus (MSSA), the presence of CC1 clones in the processing environment, including some harboring enterotoxin encoding genes, is of concern and hygiene must have high priority to reduce contamination.

Antilisterial activity of a Carnobacterium piscicola isolated from Brazilian smoked fish (surubim [Pseudoplatystoma sp.]) and its activity against a persistent strain of Listeria monocytogenes isolated from surubim.

Data on the prevalence and growth of Listeria monocytogenes in lightly preserved fish products from subtropical and tropical regions are very scarce. Our research describes L. monocytogenes that was detected in 5% of the packages of cold-smoked surubim, a native Brazilian freshwater fish that we analyzed, and shows that the strains isolated were of the same random amplified polymorphic DNA subtype as the strains that were isolated from the same factory 4 years earlier. A bacteriocinogenic strain of Carnobacterium piscicola (strain C2), isolated from vacuum-packed cold-smoked surubim, and two C. piscicola strains, isolated from vacuum-packed, cold-smoked salmon, were capable of limiting or completely inhibiting the growth of an L. monocytogenes (strain V2) isolated from surubim in fish peptone model systems incubated at 10 degrees C. Monocultures of L. monocytogenes reached 108 CFU/ml (g), whereas the growth of L. monocytogenes was completely inhibited by C. piscicola C2. The bacteriocinogenic C. piscicola A9b+ and its nonbacteriocinogenic mutant A9b- reduced maximum Listeria levels by 2 to 3 log units. Both bacteriocinogenic C. piscicola strains prevented listerial growth in cold-smoked fish juices (surubim and salmon). Although the carnobacteria grew poorly on cold-smoked surubim at 10 degrees C, the strains were able to reduce maximum Listeria counts by 1 to 3 log units in an artificially inoculated product (surubim). We conclude that Brazilian smoked fish products harbor L. monocytogenes and should be stabilized against the growth of the organism. C. piscicola C2 has the potential for use as a bioprotective culture in surubim and other lightly preserved fish, but further studies are required to optimize its effect.