Yeast Counts Research Articles

Microbial and physicochemical changes in green bell peppers treated with ultrasonic-assisted washing in combination with Thymus vulgaris essential oil nanocapsules

In this study, the effect of Thymus vulgaris essential oil (TVO) nanoemulsion (NE, 500 mg/L) in combination with ultrasound (ultrasound-NE) on the microbial and physiological quality of green bell pepper was investigated. The TVO-NE droplet size and zeta potential were 84.26 nm and − 0.77 mV, respectively. The minimum inhibitory concentrations of the TVO and TVO-NE against E. coli and S. aureus were about 0.07 and 7 g/L, respectively. The NE-ultrasound treatment exhibited the lowest peroxidase activity and respiration rate with no detrimental effect on texture, total phenolic content, antioxidant activity, pH, and TSS. Although the NE-ultrasound treatment showed the highest weight loss and electrolytic leakage, it exhibited the best visual color and appearance. The NE-ultrasound treatment descended the total viable/mold and yeast counts significantly compared to control. Results showed that treating the bell peppers with NE-ultrasound can result in bell peppers with good postharvest quality and extended shelf life.

Effect of Sorghum and Maize Malt Particle Size on Physicochemical, Stability, Microbiological, and Sensory Characteristics of Umqombothi

The consumption of Umqombothi alcoholic beverages in South Africa is widespread in townships and rural areas. This study aimed to investigate the effect of sorghum and maize malt particle size on the physicochemical, microbiological, stability, and sensory characteristics of Umqombothi. Three different particle sizes were compared, namely control, coarse, and fine powder particle sizes. Subsamples were taken at the following stages, during the production of Umqombothi: first, second, third, fourth, and fifth. Lactic acid bacteria were significantly dominant, with 8.16, 7.11, and 5.91 log cfu/mL in the final product for the control, coarse, and fine powder particle sizes. The yeast counts were 3.3, 4.64, and 5.63 log cfu/mL for the control, coarse, and fine powder particle sizes. Molds were significantly reduced to non-detectable levels after the second fermentation and the total coliforms in the final product were reduced for all particle sizes. The total soluble solids significantly decreased in the second fermentation samples. The coarse particle size exhibited significantly higher alcohol and significantly lower pH levels, which are encouraging signs for improved quality and shelf life. Different particle sizes of sorghum and maize malt affect the quality of the finished product and the production method of umqombothi.

Main Composition and Visual Appearance of Milk Kefir Beverages Obtained from Four Consecutive 24- and 48-h Batch Subcultures

Nowadays, there has been a significant rise in the consumption of kefir, a functional beverage touted for its perceived health benefits. To offer a high-quality beverage to consumers, it is imperative to scrutinize and fine-tune the fermentation process. This study seeks to investigate the impact of fermentation time and the number of subcultures on the physicochemical, microbiological, and volatile composition, as well as the visual appearance, of kefir beverages obtained from four consecutive 24- or 48-h batch subcultures. All fermented beverages exhibited low lactose, ethanol and acids levels, with counts of viable probiotic lactic acid bacteria and yeast exceeding 106 colony forming units/mL. The four kefir beverages from the 48-h batch subcultures notably showed the lowest total concentrations of volatile compounds, likely due to overfermentation and over-acidification of the beverages. This caused the separation of the whey and curd, along with the formation of large gas bubbles, negatively affecting the visual appearance of the products. These findings emphasize the importance of fine-tuning the fermentation process to ensure the production of high-quality kefir beverages that align with consumer preferences. The four beverages from the 24-h batch subcultures exhibited high microbiological and physicochemical stability during storage at 4 °C for 28 days.

Lecithin-based micellar extraction of bioactive from pomegranate peel and its application in Indian flat bread (chapati) as a bioactive emulsifier

Micellar extraction is a sustainable, eco-friendly, and cost-efficient method for extracting and recovering phenolic and flavonoid molecules from pomegranate peel. This technique traps bioactive molecules in micelles formed by a surfactant above cloud point temperature (CPT). The influence of process variables such as lecithin concentration (8–16%), pH (3−6), temperature (40–60 °C), and NaCl concentration (8–16%) on extraction was examined and then optimized numerically. For micellar separation, lecithin and salt content were the most significant (p < 0.05). The optimal variables to maximize bioactive recovery were 13.11% (w/v) lecithin concentration, 4.13 pH at 50.88 °C, and 13.89% (w/v) NaCl concentration. 88.21% of total polyphenols (TPC) and 82.64% of total flavonoids (TFC) were recovered at optimal conditions. The yields of TPC, TFC, punicalagin (PC), ellagic acid (EAC), and total hydrolyzable tannins (THTC) were 163.36 mg gallic acid equivalent/g, 24.71 mg quercetin equivalent/g, 27.29 mg/g, 8.97 mg/g, and 112.36 mg tannic acid equivalent/g of pomegranate peel, respectively. The extract exhibited good antioxidant capacity (55.18% DPPH and 39.25% ABTS). Using liquid chromatography mass spectroscopy, total 14 additional hydrolyzable tannins compounds were identified. The changes in functional groups and thermal properties of the micellar pomegranate peel extract enriched lecithin (MPEL) and pomegranate peel were effectively correlated by fourier transform infrared spectroscopy, differential scanning calorimetry, and thermogravimetric analysis. MPEL was employed to prepare chapatis. The staling, textural, and bioactive properties of MPEL-enriched chapatis were significantly improved as compared to the control chapatis. However, the color and sensory attributes of chapatis developed with and without lecithin were similar. Additionally, MPEL also controlled staling and microbial growth (AMC: aerobic mesophilic count and YMC: yeast and mold count) along with the retention of the texture of chapatis during the storage of 5 days at 5 and 25 °C.

Culturable yeast community associated with grape must and honey bees sampled from apiaries located in the vineyards.

In this study, we investigated culturable yeast community, present in grape must sampled from vineyards with apiaries on the borders, and in honey bees collected in these apiaries. To this aim, yeasts isolated from spontaneously fermented grapes randomly collected in two vineyards (P1 and P2) with apiaries on the borders (A1 and A2) were compared to those isolated from spontaneously fermented grapes collected from a vineyard without apiary (P4). At the same time, yeast community was analyzed on bees collected in each apiary placed in the vineyards, in comparison to yeasts isolated from an apiary (A3) located far from the vineyards. The analysis was performed for two consecutive years (2021 and 2022). The isolated yeasts were identified by restriction analysis of amplified ITS region, followed by sequencing of ITS fragment.Our research showed that the presence of apiaries seems to increase yeast counts of grape must, in particular of Saccharomyces cerevisiae; furthermore, the permanence of apiaries in the vineyards allowed the recovering of these yeasts also from bees. Our findings seem to corroborate the role of bees as vectors and reservoirs of oenologically relevant yeasts, such as a source of non-conventional yeasts with potential biotechnological applications.

ANTIBACTERIAL POTENTIAL AND MICROBIOLOGICAL QUALITY OF HONEY FROM SLOVAKIA

In this study, the antibacterial activity of 10 honeys at three concentrations 50%, 25%, and 12.5% was tested against two G- and two G+ strains, also the microbiological quality of the honeys in terms of the representation of total count of bacteria, coliforms, yeasts, and filamentous fungi was evaluated, and micromycetes to the species level were identified. Antibacterial activity of the honeys was assayed using well diffusion method, determination of microbial groups by the pour plate method and diversity of mycobiota in honey according to macro- and micromorphological characteristics. Results showed the antibacterial effects of Slovak honey collected from the Spiš region, against bacterial strains Escherichia coli, Pseudomonas fluorescens, Enterococcus faecalis, and Staphylococcus aureus, which are among the most common bacteria responsible for nosocomial infections. We found that honeydew honey was very effective against E. coli and S. aureus, rapeseed honey against P. fluorescens, and mixed honey (no. 10) against E. faecalis. Staphylococcus aureus was the most susceptible bacteria tested for all honeys. The presence of both yeasts and molds was detected in 3 honey samples at concentrations ranging from &lt;4x101 to 3.6x101 CFU/g, while the total count of bacteria was detected in 9 samples at concentrations ranging from 2.3x101 to 3.6x102 CFU/g (in 1 sample, the occurrence of microorganisms was not recorded even at the lowest dilution of 10-1). Coliforms were not isolated. A total of 3 strains belonging to the Aspergillus section Nigri were identified. The microbiological analyses of the samples indicates that the honeys were produced, processed and stored in accordance with the rules of good hygiene practice.

Integrated approach of ultrasound with mild heat treatment on the quality characteristics of yacon (Smallanthus sonchifolius) tuber juice

AbstractThe research delved into the ascendancy of thermosonication (TS) on elevating the alimentary components of yacon (Smallanthus sonchifolius) tuber juice, derived from the yacon plant. This investigation introduces an innovative approach utilizing artificial neural networks (ANNs) coupled with genetic algorithm (GA) for the multifaceted optimization of extraction procedures. It aims to pinpoint the most effective processing parameters for TS, including variations in amplitudes: X1 (40, 50, and 60%) and temperatures: X2 (30, 40, and 50°C) over sonication times: X3 (15, 30, 45, and 60 min). Further, the approach is focused to amplify quality of yacon juice (YJ) and microbial attributes by enhancing certain quality characteristics such as anti‐oxidant activity (AOA), ascorbic acid (AA), total phenolic content (TPC), total carotenoid content (TCC), total flavonoid content (TFC), yeast and mold count (YMC) and total viable count (TVC). The maximum levels of AOA (33.73 ± 2.21%), AA (25.82 ± 2.03 mg/100 ml), TPC (85.08 ± 3.67 mg GAE/ml), TCC (115.82 ± 2.46 βCE μg/ml), TFC (22.52 ± 2.11 mg QE/ml), TVC, and YMC (not detected) were achieved in thermosonicated YJs under optimal conditions using ANN coupled with GA.Practical ApplicationsYacon tuber juice (YJ) treated with thermosonication (TS) showed improved nutritional characteristics, making them a valuable source of functional compounds for nutraceuticals and food industries. Research emphasizes the effectiveness of artificial neural network in predicting the extraction efficiency of YJ and proposes TS as a potential replacement for traditional thermal pasteurization to maintain or enhance YJ quality and functionality. TS provides cost‐effective and sustainable solutions to the food industry by reducing processing time and energy consumption when compared to pasteurization.

In-ovo injection of Bacillus subtilis, raffinose, and their combinations enhances hatchability, gut health, nutrient transport- and intestinal function-related genes, and early development of broiler chicks

An experiment was conducted to assess the response of chicks to in-ovo injection of Bacillus subtilis (probiotic), raffinose (prebiotic), and their combinations. The study used 1,500 embryonated eggs allotted to 10 groups/ 6 replicates (150 eggs/group). The experimental treatments were: 1) un-injected control (NC); 2) sham (sterile distilled water) (PC); 3) probiotic 4 × 105CFU/egg (LBS); 4) probiotic 4 × 106CFU/egg (HBS); 5) prebiotic 2 mg/egg (LR); (6 prebiotic 3 mg/egg (HR); 7) probiotic 4 × 105CFU + prebiotic 2 mg/egg (LBS+LR); 8) probiotic 4 × 105CFU + prebiotic 3 mg/egg (LBS+HR); 9) probiotic 4 × 106CFU + prebiotic 2 mg/egg (HBS+LR); and 10) probiotic 4 × 106CFU + prebiotic 3 mg/egg (HBS+HR). Results showed that in-ovo inclusion of Bacillus subtilis, prebiotic, and their combinations improved hatchability, yolk-free chick weight, and chick weight compared to the control group. Moreover, the in-ovo treatment reduced residual yolk weight on the day of hatch compared to the control group. Different levels of in-ovo B. subtilis alone or combined with raffinose significantly (P ≤ 0.001) reduced total bacterial count and total yeast and mold count compared to the negative control group. Total coliform and E. coli decreased significantly (P ≤ 0.001) in groups treated with probiotics, prebiotics, and synbiotics with different doses during incubation compared to those in the control. Clostridium spp. was not detected in the groups injected with B. subtilis alone or combined with raffinose. In-ovo probiotics and synbiotics (LBS+LR & LBS+HR) significantly (P ≤ 0.001) increased ileal villus length compared to other groups. In-ovo treatment increased mRNA expression of JAM-2 compared to the control group. The fold change significantly increased in group LBS+HR for genes MUC-2, OCLN, VEGF, SGLT-1, and EAAT-3 compared to the negative control. In conclusion, in-ovo injection of a low dose of B. subtilis plus a high or low dose of raffinose can positively affect hatching traits, cecal microbial populations, intestinal histomorphometry, nutrient transport- and intestinal function-related genes, and chick quality of newly hatched broiler chicks.

Psychrotrophic Bacteria and Yeast Populations in Turkish White and Tulum Cheeses

In this study, pH and microbiological (psychrotrophic bacteria and yeast) properties of White and Tulum cheeses were investigated. According to the results of our study, the lowest pH value identified was 4.42, and the highest pH was 5.84 in the cheese samples. Psychrotrophic bacteria counts ranged from 4.15 to 6.21 log CFU/g for White cheese and 4.02 to 6.15 log CFU/g for Tulum cheese. Psychrotrophic yeast counts ranged from 2.98 to 7.58 log CFU/g for White cheese and 2.99 to 6.77 log CFU/g for Tulum cheese. The highest values of psychrotrophic yeast were detected in the Tulum cheese samples. As a result, it was determined that the numbers of psychrotrophic bacteria and yeast were high in both Tulum and White cheese samples. These high numbers of psychrotrophic microorganisms during cheese storage in the refrigerator may increase even further and reduce shelf life. To extend the shelf life of these cheeses, it is recommended to ensure hygienic handling practices and explore the use of natural preservatives or modified atmosphere packaging.

Process optimization of thermosonicated modhusuleng (polygonum microcephalum) leaf juice for quality enhancement using response surface methodology

The present study investigated the impacts of pasteurization and thermosonication on various aspects of modhusuleng (Polygonum microcephalum) leaf juice, including its physico-chemical, functional, and microbial attributes (total plate count, yeast and mold count). Juices underwent thermosonic treatments at varied durations (30, 45, and 60 min) and temperatures (30, 40, and 50 °C), utilizing two distinct frequencies (33 and 44 kHz). The application of pasteurization (PS) and thermosonication (TS) did not exhibit any noticeable effects on pH, total soluble solids (TSS), or titratable acidity (TA). Post TS, there were enhancements in antioxidant activity, total phenolic content (TPC), total flavonoid content (TFC), cloudiness value, browning index, total carotenoid content, and chlorophyll content. However, the ascorbic acid content in the leaf juices decreased post TS. Process optimization was carried out through the application of response surface methodology (RSM). For 33 kHz, the predicted values were - Antioxidant - 68.23 %, TPC - 183.11 mg GAE/100 mL, TFC - 3.15 mg QE/mL, and Ascorbic acid - 24.45, while for 44 kHz, the values were obtained as - Antioxidant - 60.80 %, TPC - 212.97 mg GAE/100 mL, TFC - 3.40 mg QE/mL, and Ascorbic acid - 25.53. The model's suitability is highlighted by the small difference between the expected and actual values. The results revealed that leaf juice samples treated at 50 °C with a frequency of 44 kHz for 60 min exhibited higher TPC, TFC, and antioxidant activity when compared to samples subjected to alternative temperature and frequency conditions. TS also led to a significant reduction in bacterial populations in the juices. While thermal treatment rendered the microbes inert, it adversely impacted the quality indices. The study suggests that modhusuleng juice quality features can be preserved even after undergoing thermosonic processing. TS is suggested as a favorable technique for modhusuleng leaf juice processing, given its potential to enhance antioxidant activity, preserve quality features, and reduce bacterial populations.

The microbiota of ensiled forages and of bulk tank milk on dairy cattle farms in northern Sweden

Factors contributing to variations in the quality and microbiota of ensiled forages and in bulk tank microbiota in milk from cows fed different forages were investigated. Nutritional quality, fermentation parameters and hygiene quality of forage samples and corresponding bulk tank milk samples collected in 3 periods from 18 commercial farms located in northern Sweden were compared. Principal coordinates analysis revealed that the microbiota in forage and bulk milk, analyzed using 16S rRNA gene-based amplicon sequencing, were significantly different. The genera Lactobacillus, Weissella, and Leuconostoc dominated in forage samples, whereas Pseudomonas, Staphylococcus, and Streptococcus dominated in bulk milk samples. Forage quality and forage-associated microbiota were affected by ensiling method and by use of silage additive. Forages stored in bunker and tower silos (confounded with use of additive) were associated with higher levels of acetic and lactic acid and Lactobacillus. Forage ensiled as bales (confounded with no use of additive) was associated with higher DM content, water-soluble carbohydrate content, pH, yeast count, and the genera Weissella, Leuconostoc, and Enterococcus. For bulk tank milk samples, milking system was identified as the major factor affecting the microbiota and type of forage preservation had little effect. Analysis of common amplicon sequence variants (ASV) suggested that forage was not the major source of Lactobacillus found in bulk tank milk.

Augmenting the Quality and Shelf Life of Ras Cheese by Adding Microencapsulated Allspice Berry Extract Nanoemulsion

AbstractThe current study was achieved to increase phenolic compounds and antioxidant content in Ras cheese by microencapsulation of the nanoemulsion of extract from the berries of allspice. The microencapsulation of the extract nanoemulsion from the berries of allspice using maltodextrin, whey protein concentrate, and guar gum was prepared by a freeze-drying process. The extract was cured, and nanoemulsion forms were prepared and evaluated for the antimicrobial effect and phenolic compound content. The morphology of microcapsules was studied by transmission electron microscopy (TEM) and Fourier-transform infrared spectroscopy (FT-IR) analysis. The prepared microcapsules were added to Ras cheese using ratios (1, 2, and 3% (w/w)) and then stored for 120 days for ripening and examined chemically, microbiologically, and organoleptically. The results indicated that the allspice extract in both forms has shown an inhibitory effect on all microorganisms. Moreover, the major phenol compound in allspice berry extract was gallic acid with quantities of 15,991 µg/g. Furthermore, the microcapsule efficiency was recorded at 80.97% and spherical with a diameter of 380 µm, while the nanoemulsion of extract as the core has a size of around 320 nm. The total lactic acid bacteria counts in all samples gradually declined during the ripening period. The mold and yeast count was not detected in fresh cheeses and appeared for cheese control more than in cheese with the extract. Cheese control and treatments contained lower titratable acidity, total nitrogen, soluble nitrogen, and ash ratio than the other cheese with extract treatments. The total volatile fatty acids (TVFAs) were increased through the storage period in all cheese treatments. Correspondingly, Ras cheese acceptability for sensory evaluation increased during the ripening periods in all treatments, whereas cheese supplemented with 1% microcapsules ranked the highest score for flavor and body and texture during storage gaining a high accepted point of 93.62.

Dietary supplementation with copper nanoparticles enhances broiler performance by improving growth, immunity, digestive enzymes, and gut microbiota

The aim of this work is to measure the influence of copper nanoparticles (CuNPs) on growth performance, carcass traits, renal and hepatic indices, immunity, lipid profile, antioxidant status, blood minerals, digestive enzymes, and cecal microbiota in broilers. 300 unsexed one-week-old Arbor Acre broiler chicks in total were randomly assigned into 5 treatment groups of 60 chicks per eachwhich were divided into 5 replicates of 12 chicks. The 1st group (G1) was given basal diet (only); the 2nd group (G2), the 3rd group (G3), the 4th group (G4) and the 5th group (G5) were given basal diet treated with CuNPs at a rate of 5, 10, 15, and 20 mg/kg diet, respectively. The result revealed a significant improvement (P < 0.01) in performance paramters where the best values of body weight, weight gain, and feed conversion ratio were achieved at 15 mg/kg diet (CuNPs). Moreover, CuNPs supplementation significantly (P < 0.05) improved carcass traits specially carcass, dressing, giblets, and liver percentage, particularly at 15 mg/kg diet which revealed the best results. Furthermore, CuNPs supplementation at all tested levels increased the immune organ's weight (spleen and thymus). Plasma total protein and globulin were increased with CuNPs supplementation at levels 10 to 20 mg/kg diet. CuNPs supplementation (10-20 mg/kg diet) significantly improved liver and renal function by lowering the levels of AST, creatinine and uric acid. Moreover, CuNPs supplementation significantly (P < 0.05) improved lipid profile indicated by decreased the levels of cholesterol, triglyceride, low-density lipoprotein cholesterol, very low-density lipoprotein cholesterol as well as malondialdehyde (MDA). CuNP supplementation significantly improved broiler immunity indicated by increased IgA, IgM, complement (C3) and lysozyme, where CuNPs at 15 and 20 mg/kg diet revealed the best results. CuNPs supplementation increased reduced glutathione (GSH), total antioxidant capacity (TAC), and superoxide dismutase (SOD) as well as increased blood minerals (Cu, Fe, P, and Ca). Also, the digestive enzymes of broiler chicks treated with CuNPs significantly increased (P < 0.05), such as lipase, protease, and amylase enzymes. The findings revealed a significant elevation in total bacterial count (TBC) and lactic acid bacteria and significantly decreased total yeast and mold count (TYMC), E. coli, Salmonella and Coliform. In conclusion, CuNPs supplementation significantly improves performance, carcass yield, renal and hepatic indices, lipid profile, immunity, antioxidants, blood minerals, digestive enzymes, and cecal microbiota of broiler chicks.

Effects of fruit and vegetable waste addition on corn stalk silage quality.

In this study, we explored the effect of fruit and vegetable waste addition on the quality of corn stalk silage. Corn stalks were ensiled 20 days after ear harvesting and mixed with fruit and vegetable waste (FVW) consisting of apple, orange, broccoli, and Chinese cabbage waste as 3% of fresh matter. Fruit waste consisted of solid residue obtained after juicing, and vegetable waste was collected from farms and cut into small pieces (2 to 3 cm). The materials were stored anaerobically in 20-L silo buckets and opened after 60 days of fermentation. There were significant differences in dry matter (DM), acid detergent fiber (ADF), neutral detergent fiber (NDF), total digestible nutrient (TDN), and relative feed value (RFV) levels in FVW derived from all tested raw materials (p<0.05). Corn stalk mixed with orange waste (CSOW) had the highest DM content (28.77%), lowest ADF and NDF content (47.78% and 26.62% of DM, respectively), and highest TDN and RFV content (69.21 and 133, respectively). After 60 days, there were significant differences in all chemical parameters examined (p<0.05). Corn stalk mixed with broccoli waste (CSBW) had the lowest DM loss (2.23%), and the CSOW group had the lowest NDF and ADF content and highest in vitro DM digestibility. CSBW had the lowest pH and ammonia nitrogen content, but the highest lactic acid/acetic acid ratio among the treatment groups. CSOW had the highest lactic acid content (2.27% of DM). The microbial contents of each group differed only in lactic acid bacteria counts before and after ensiling, showing a slight increase (p>0.05) and significant decreases in yeast and mold counts (p<0.05) after ensiling. These findings confirmed that mixing various FVW materials, particularly orange waste, with corn stalks improved the nutritional value of silage. Adding broccoli waste resulted in better fermentation quality than the addition of other FVW materials.

The effect of lemon juice addition and cold storage on the total phenolic content and antioxidant activity of cold mate tea

Although mate tea, made from the infusion of the Ilex paraguariensis plant, is typically consumed cold, it should be properly prepared, stored, and consumed within the appropriate time frame to fully appreciate the tea’s aroma and components. This study aimed to investigate the impact of adding lemon juice to mate tea and cold storage on the total phenolic content, antioxidant activity, and total mold and yeast count of the tea. It was hypothesized that the addition of lemon juice would increase the total phenolic content and antioxidant activity and extend shelf life. At the start of storage, the sample with 2% (v/v) lemon juice added showed the highest total phenolic content (14.06 ± 0.05 mg GAE/100 mL). The antioxidant scavenging activity of the tea samples was investigated using the DPPH (2,2-diphenyl-1-picrylhydrazyl) method. While all the studied sample showed higher DPPH inhibition than the control group, the highest value was found for tea sample with 4% lemon addition on 3rd day (97.618 ± 1.429). No mold or yeast growth was observed in the control group and the samples with 2% and 4% lemon juice addition up to day 21. In the sensory evaluation, the tea that contained 4% lemon juice was the most preferred. In conclusion, if mate tea is prepared and stored appropriately, it can maintain its antioxidant capacity for an extended period without the formation of harmful molds or yeasts and any deterioration in its sensory properties.

The effect of washing for the shelf-life parameters of spinach (Spinacia oleracea L.)

Spinach is a very popular green leafy vegetable because of its versatile usage and beneficial for the health. However, spinach may contain several pathogen bacteria: Escherichia coli, Klebsiella spp., Salmonella spp., Enterobacter spp., Citrobacter spp., Shigella spp. and Listeria monocytogenes, which can cause several serious health problems. This study investigates the effects of washing with citric acid for the shelf-life parameters of spinach in comparison to the effect of washing with water and control. Washing of spinach with 0.5% citric acid solution decreased the elasticity of the spinach leaves, as well as the chlorophyll content. On the other hand, the total plate count, as well as the yeast and mold count could be decreased with this treatment, but difference was not detectable at the forth storage day. The fecal indicator E. coli did not change, indicating washing was not effective in this case. Further optimisation of treatment and storage conditions may decrease microbial risk of fresh spinach consumption without decreasing its sensory quality.

Storage Stability of jaggery based sesame spread: A comprehensive study

The shelf life of a spread product is a critical factor in its formulation, production, and marketing. Consumers expect sesame spread products retain a fresh appearance, odor, and flavor for an extended period, as a longer shelf life decreases costs for both producers and consumers. Therefore, the objective of this investigation was to evaluate the storability of jiggery based sesame spread (JSS). The storability of developed JSS were of analyzed for physicochemical characteristics (Moisture, Protein, Carbohydrate, Fat, Crude fibre, Ash, Calorific value, Oil separations, Oxalic acid, Peroxide value and Acid value), Rheological parameters (Adhesiveness, Cohesiveness, Hardness and Viscosity), sensory attributes (Taste, Colour, Appearance, Spreadability, Flavour and Overall Acceptability) and microbiological quality (Standard plate count, Yeast and Mould count and Escherichia coli.) of JSS. The investigational storages were carried out for 90 days at room temperature storage (24 ± 4°C, 40-50% RH) and refrigerated (8°C, 17-20% RH) storage. The results indicated significant increase in oil separations, peroxide value, acid value, microbial counts, and sensory parameters of the spread. However, the remaining analyzed quality attributes of the spread demonstrated stability. The oil separations in spread sample were found to be highest during room temperature storage, which could be attributed to the temperature fluctuations experienced during storage. In conclusion, it is highly recommended to carefully manage the storage temperature of sesame spread to ensure its stability.

The effect of chitosan-furcellaran biopolymeric films and coatings incorporated with LL-37 and RW4 bioactive peptides on the microbiological and sensory quality of cheese

The study objective was to investigate the influence of chitosan-furcellaran films and coatings with bioactive peptides on cheese properties. The films were prepared using the casting method while the coatings by the dip-coating process. The yeast and mold count (YMC) was positive in the control Gouda after the 2nd week of storage. However, only after week 3 were yeast and mold detected in the samples covered with the RW4 film and in the coatings with no peptide or containing LL-37 (3.1–3.8 log cfu g−1). Regarding Mozzarella, a significant increase in YMC was determined after week 2 of storage in samples having coatings with no peptide or with LL-37 (6.2–6.3 log cfu g−1), whereas after the 1st week, YMC was increased in the control (6.6 log cfu g−1). The coatings with no peptide and with LL-37 demonstrated the best influence on microbiological quality, while having no negative impact on Gouda or Mozzarella sensory properties.

Evaluation of Microbial Quality of Fufu Samples Prepared Using Conventional and Mechanical Methods in Kumasi Metropolis

Aim: The study aimed at evaluating the microbial quality of conventionally (CV) and mechanically (MC) prepared fufu samples in the Kumasi Metropolis of Ghana. Study Design: The study used 2 x 5 x 2 experimental design constituting two fufu preparation methods (CV and MC), five different vending locations, and two sample types (fufu samples and water samples) from each vendor. Materials and Methods: A total of ten (10) fufu and water samples each were conveniently collected and analysed using standard microbiological procedures. Place and Duration of Study: The study was carried out in the Kumasi Metropolis of Ghana, in March 2022. Results: The total aerobic count in the conventional and mechanical prepared samples ranged from 5. 2×107cfu/g to 4.5×108cfu/g and 5. 4×107cfu/g to 1.35×108cfu/g respectively. The total aerobic count in the water samples ranged between 9.7×106cfu/ml and 1.35×109cfu/ml in (CV) and 1.53×106cfu/ml – 6.3×108cfu/ml in (MC). Both the fufu and water samples from the vendors had unsatisfactory levels of total and faecal coliform count, Staphylococcus aureus count, and yeast count irrespective of the processing method (CV and MC). Conclusion: The fufu processing methods did not influence its microbial qualities positively. Hence Good Hygienic Practices are essential to ensure its microbiological safety.

Drying Kinetics and Quality Attributes of Solar-Dried Red Peppers: A Comparative Study with Traditional and Industrial Methods

Red pepper is a valuable ingredient known for its abundance of vitamins and antioxidants. But, it usually needs to be dried for longer preservation. Hence, this research is aimed at examining the drying kinetics and quality attributes of dried red peppers utilizing various solar drying methods, in comparison with traditional open sun drying (OSD) and industrial laboratory thin layer dryers (LTLD). Analysis parameters employed include determining moisture content, measuring color properties, evaluating antioxidant capacity, analyzing capsaicinoid content, and assessing microbial presence. The drying process took place in a sunny environment with fluctuations in temperature and relative humidity as evidence of the dynamic conditions experienced within the solar dryers. It was observed that the logarithmic model was the most accurate in predicting moisture ratio over time, estimating a drying time of 25 hours to achieve 10% moisture content. The result demonstrated that direct solar dryers (DSD), indirect solar dryers (ISD), and mix mode solar dryers (MMSD) methods showed moderate changes in color parameters, with average ΔL∗, Δa∗, and Δb∗ values of -5.08, -23.71, and -13.62, respectively. The average overall color difference (ΔE) for these methods was 27.96. In addition, after comparing it to the LTLD method, which showed the highest content of phenolic compounds at 47.89%, MMSD displayed a slightly lower content of 44.71%. Similarly, MMSD exhibited higher levels of DPPH radical scavenging activity and ferric reducing power, measuring at 44.22% and 1163.75 μmol Fe2+/L, respectively. The capsaicin content remained relatively consistent across all drying methods, with MMSD, DSD, and LTLD demonstrating similar levels of approximately 31 mg/g. Although MMSD had slightly higher mold and yeast counts compared to LTLD, ISD, and DSD, it remained lower than OSD (less than 0.56 log10cfu/g). Furthermore, MMSD showed a lower total microbial count in comparison to other drying methods. These findings suggest that MMSD shows promise as a drying technique for preserving the phenolic compounds and antioxidant activity of the dried product.