Enterotoxigenic Staphylococcus aureus in Brazilian artisanal cheeses: Occurrence, counts, phenotypic and genotypic profiles.

The present study aimed to assess the occurrence and counts of Staphylococcus aureus in Brazilian artisanal cheeses (BAC) produced in five regions of Brazil: Coalho and Manteiga (Northeast region); Colonial and Serrano (South); Caipira (Central-West); Marajó (North); and Minas Artisanal cheeses, from Araxá, Campos das Vertentes, Cerrado, Serro and Canastra microregions (Southeast). The resistance to chlorine-based sanitizers, ability to attach to stainless steel surfaces, and antibiogram profile of a large set of S. aureus strains (n = 585) were assessed. Further, a total of 42 isolates were evaluated for the presence of enterotoxigenic genes (sea, seb, sec, sed, see, seg, sei, sej, and ser) and submitted to typing using pulsed-field gel electrophoresis (PFGE). BAC presented high counts of S. aureus (3.4-6.4 log CFU/g), varying from 25 to 62.5%. From the S. aureus strains (n = 585) assessed, 16% could resist 200 ppm of sodium hypochlorite, whereas 87.6% produced strong ability to attach to stainless steel surfaces, corroborating with S. aureus ability to persist and spread in the environment. Furthermore, the relatively high frequency (80.5%) of multidrug-resistant S. aureus and the presence of enterotoxin genes in 92.6% of the strains is of utmost attention. It reveals the lurking threat of SFP that can survive when conditions are favorable. The presence of enterotoxigenic and antimicrobial-resistant strains of S. aureus in cheese constitutes a potential risk to public health. This result calls for better control of cheese contamination sources, and taking hygienic measures is necessary for food safety. More attention should be paid to animal welfare and hygiene practices in some dairy farms during manufacturing to enhance the microbiological quality of traditional cheese products.

Investigating desiccation resistance, post-rehydration growth, and heat tolerance in desiccation-injured cells of Salmonella enterica isolated from the soybean production chain.

This study compared the resistance to different desiccation conditions of 190 Salmonella enterica strains previously isolated from the soybean meal production chain and belonging to 23 serovars. Additionally, the post-rehydration growth and heat tolerance of the strains previously exposed to desiccation were determined. Variability in desiccation resistance was observed both within and between serovars. Strains belonging to S. Havana and S. Schwarzengrund serovars were the most resistant, regardless of storage condition. The drying temperature (20 °C and 30 °C) did not influence the desiccation resistance of the Salmonella strains. On the other hand, increasing drying time from 1 to 7 days reduced Salmonella counts. The origin (isolation sources) also influenced the desiccation resistance of the Salmonella strains. The growth of the Salmonella strains after rehydration varied considerably depending on the drying conditions and incubation temperature during cultivation. An increase in the time and temperature of drying led to a reduction in population of most Salmonella strains after rehydration. Salmonella strains previously desiccated also showed differences in the heat tolerance in all temperature-time binomials tested. Some strains were highly resistant to heat tolerance conditions, presenting <1 log CFU/mL reduction from the initial population. The results obtained in this study suggest that the strategies to mitigate Salmonella in low-aw foods must consider the existence of high-stress resistant strains and their multiple-stress adaptability profiles, including effects of processing, food composition, and storage conditions.

Wheat-durum pasta added of inactivated Bifidobacterium animalis decreases glucose and total cholesterol levels and modulates gut microbiota in healthy rats.

This study investigated the effects of consumption of wheat-durum pasta added of Bifidobacterium animalis inactivated by gamma-irradiation (paraprobiotic) on health and gut microbiota of rats. Twenty-one male rats were divided into three groups as follow: control (Control) receiving standard diet; pasta control (PC) receiving diet containing pasta, and paraprobiotic pasta Bifidobacterium-irradiated (PPBI), receiving paraprobiotic pasta. The serum levels of glucose and total cholesterol were reduced (p < 0.05) in PPBI when compared to the Control (p < 0.05). PPBI showed high abundance (p ˂ 0.05) of Firmicutes and Actinobacteria and a lower abundance of Bacteriodes compared to Control and PC. Besides, the PPBI showed high abundance (p ˂ 0.05) of Clostridiales, Lactobacillales; Bifidobacteriales, Bacillales, and Coriobacteriales in comparison to Control. Specific genera such as Bifibacterium, Lactobacillus, Ruminococcus, Allobaculum, and Blautia were more related to PPBI. Findings reveal wheat-durum pasta as a potential vehicle for delivering paraprobiotics B. animalis.

Ohmic heating does not influence the biochemical properties of Minas Frescal cheese but decreases uric acid levels in healthy Wistar rats.

The objective of this study was to evaluate the effects of the consumption of Minas Frescal cheese (2 g for 15 d) produced with pasteurized milk or milk subjected to ohmic heating on the health variables (biochemical, hematological, and uric acid levels) of rats, as well as on the identity variables and proteolysis indices of cheese. Three groups of rats (n = 6 per group) were studied, as follows: control group, without cheese consumption (CON), rats fed Minas Frescal cheese produced with milk pasteurized by conventional technology (PC, 72 to 75°C for 15 s), and rats fed Minas Frescal cheese produced with milk subjected to ohmic heating (OHC, 8 V/cm, 72 to 75°C for 15 s). Ohmic heating did not alter the macronutrient levels (moisture, fat, protein) of the cheeses, but an increase in the proteolysis index was observed. For both cheeses, no significant differences were observed for feed intake (139 to 143 g/d), water consumption (196 to 206 mL/d), or final animal weight (236 to 252 g), and no changes were detected in hematological variables (counts of red blood cells, hemoglobin, leukocytes, and platelets) or levels of potassium, calcium, magnesium, urea, creatinine, total cholesterol, high-density lipoprotein cholesterol, blood glucose, and bilirubin (total, direct, and indirect) of rats. In addition, both cheeses led to a reduction of serum triglycerides and an increase in monocyte, eosinophil, and basophil levels. However, consumption of OHC resulted in decreased sodium, uric acid, and lymphocyte levels. The present results suggest that ohmic heating in the processing of Minas Frescal cheese has positive effects on the health of healthy rats.

The presence of ochratoxin A does not influence Saccharomyces cerevisiae growth kinetics but leads to the formation of modified ochratoxins.

Yeasts are able to reduce the levels of ochratoxin A in fermentative processes; and, through their enzymatic complex, these micro-organisms are also capable of forming modified mycotoxins. These mycotoxins are often underreported, and may increase health risks after ingestion of contaminated food. In this sense, this study aims to evaluate whether the presence of ochratoxin A influences yeast growth kinetic parameters and to elucidate the formation of modified ochratoxin by Saccharomyces cerevisiae strains during fermentation. Three S. cerevisiae strains (12 M, 01 PP, 41 PP) were exposed to OTA at the concentrations of 10, 20 and 30 µg/L. The Baranyi model was fitted to the growth data (Log CFU/mL), and the identification of modified ochratoxins was performed through High Resolution Mass Spectrometry. The presence of ochratoxin A did not influence the growth of S. cerevisiae strains. Four pathways were proposed for the metabolization of OTA: dechlorination, hydrolysis, hydroxylation, and conjugation. Among the elected targets, the following were identified: ochratoxin α, ochratoxin ß, ochratoxin α methyl ester, ochratoxin B methyl ester, ethylamide ochratoxin A, ochratoxin C, hydroxy-ochratoxin A, hydroxy-ochratoxin A methyl ester, and ochratoxin A cellobiose ester. These derivatives formed from yeast metabolism may contribute to the occurrence of underreporting levels of total mycotoxin in fermented products.

Probiotic Prato cheese attenuates cigarette smoke-induced injuries in mice.

The efficacy of probiotic Prato cheese against the inflammatory and oxidative damage in mice organs induced by cigarette smoke exposure was investigated. Forty C57BL/6 male mice were assigned to four groups: (CS) exposed to cigarette smoke and fed regular chow; (CS + C) exposed to cigarette smoke and fed daily conventional cheese ad libitum; (CS + PC) exposed to cigarette smoke and fed daily probiotic (Lactobacillus casei-01) cheese ad libitum; and a control group (C) exposed to ambient smoke-free air and fed regular chow. Bronchoalveolar lavage (BAL), blood, gut and liver homogenates were used for biochemical assays. The (CS + PC) group exhibited fewer BAL leukocytes, reactive oxygen species (ROS), and BAL and gut lipid peroxidation than the (CS) and (CS + C) groups, which had findings similar to the (C) group. Probiotic cheese consumption did not change the red blood cell count, but lower lactate dehydrogenase (LDH) levels in plasma, inducible nitric oxide synthase (iNOS) and peroxynitrite expression were observed compared to the (CS) and (CS + C) groups, with findings similar to the (C) group. These results suggest that probiotic Prato cheese consumption reduced oxidative stress in the lungs, gut, and liver.

Probiotics in Goat Milk Products: Delivery Capacity and Ability to Improve Sensory Attributes.

Dairy foods, particularly those of bovine origin, are the predominant vehicles for delivery of probiotic bacteria. Caprine (goat) milk also possesses potential for successful delivery of probiotics, and despite its less appealing flavor in some products, the use of goat milk as a probiotic carrier has rapidly increased over the last decade. This review reports on the diversity, applicability, and potential of using probiotics to enhance the sensory properties of goat milk and goat milk-based products. A brief conceptual introduction to probiotic microorganisms is followed by an account of the unique physicochemical, nutritive, and beneficial aspects of goat milk, emphasizing its advantages as a probiotic carrier. The sensory properties of probiotic-enriched goat milk products are also discussed. The maintenance of probiotic viability and desirable physicochemical characteristics in goat milk products over shelf life is possible. However, the unpleasant sensory features of some goat milk products remain a major disadvantage that hinder its wider utilization. Nevertheless, certain measures such as fortification with selected probiotic strains, inclusion of fruit pulps and popular flavor compounds, and production of commonly consumed tailor-made goat milk-based products have potential to overcome this limitation. In particular, certain probiotic bacteria release volatile compounds as a result of their metabolism, which are known to play a major role in the aroma profile and sensory aspects of the final products.