Total Aerobic Bacterial Counts Research Articles

Assessment of the microbiological quality of tiger nut (Cyperus esculentus) drink sold in Ignatius Ajuru University of Education, Port Harcourt, Nigeria

This research work assessed the microbiological quality of tiger nut juice (Cyperus esculentus L.) sold at Ignatius Ajuru University of Education, Port Harcourt. A total of six samples were purchased from different vendors selling in the University main campus. Microbiological analysis was done using nutrient agar, MacConkey agar and Potato dextrose agar media to culture, enumerate and isolate organisms from the samples. The total aerobic heterotrophic bacterial count, coliform count, and fungal count, were estimated by the pour plate techniques. The results revealed that total heterotrophic bacterial count ranged 1.11×105 to 2.40×105 cfu/ml, while the total coliform count ranged from 1.54×105 to 3.10×105 cfu/ml. The total staphylococcus and yeast count ranged from 1.44×105 to 2.61×105 cfu/ml. The high coliform count and the isolation of pathogenic bacteria in some samples indicate that the Tiger nut drink was contaminated and a potential health hazard to the unsuspecting consumers. The producers and vendors of tiger nut drink should be enlightened on the consequences of poor hygiene and the need to adopt good manufacturing practices in the preparation and storage of the drink to prevent the outbreak of epidemics.

Limiting Microbial Activity as an Alternative Approach of Bovine Hide Preservation Part II

Wet salting of bovine hide commonly utilizes 95% saturated salt solution or 40-50% salt (w/w) on raw hide weight for preservation. The salt used for the hide preservation ends up being in wastewater and generates enormous environmental pollution. To minimize the environmental pollution problem associated with the traditional method of hide preservation, alternative formulations containing antimicrobial agents and less amount of common salt (35% saturated brine) have been developed. The alternative formulations were found to be more effective in deterring microbial growth than the traditional formulation as demonstrated by the total aerobic bacterial count of the preserved hide soaking liquor. The effect of the newly developed formulations on leather quality was assessed by analyzing the mechanical properties, scanning electron microscopic images, grain pattern and organoleptic properties of the finished leather. The quality analysis of the crust leather revealed that, the leather panels produced from the traditionally and alternatively preserved hides were comparable. The environmental impact of the newly developed formulations was also evaluated by monitoring the leather processing effluents for the pollution indicators such as total solids (TS), total dissolved solids (TDS), chloride content, Chemical oxygen demand (COD) and Bio-Chemical oxygen demand (BOD). Overall, the environmental impact of the newly developed hide preserving formulation was less severe than the traditionally used formulation. Since the newly developed formulations did not affect the quality of the leather produced and their impact on the environments is minimum, they could be considered as viable options for combatting pollution problems associated with the traditional salt curing method.

Effects of Macleaya cordata extract supplementation in milk on growth performance, some biochemical parameters and a number of selected bacterial groups of the recto-anal microbiota of calves

The objective of this study was to investigate the effects of milk Macleaya cordata extract supplementation on the weight gain, feed intake, serum total protein (TP), albumin, globulin, IgG, blood urea nitrogen (BUN), triglyceride (TG), beta-hydroxy butyric acid (BHBA) levels, alkaline phosphatase (ALP), aspartate aminotransferase (AST), alanine aminotransferase (ALT) levels and total aerobic, lactobacillus and coliform bacterial counts of recto-anal swabs in Simmental calves. The feeding study was carried out using 20 (n = 10) 4-day-old Simmental calves (average birth weight 45.55 ± 1.53 kg) from December 2017 to May, 2018. The experimental treatments comprised milk without any additive (control) and milk with 1 g M. cordata extract added per head per day. The calves were fed with only colostrum until 4 days of age and then with 5 liters per day of whole milk until the end of 65 days. At the end of the study, a significant difference in body weights and feed efficiency between the groups was not observed. During the 4th-6th weeks of the trial, M. cordata extract supplementation in milk decreased the feed intake of the calves. The serum TP, albumin, IgG, BHBA, TG, BUN, ALP and ALT levels were also found to be not statistically different between the treatment groups. At the end of the experiment the serum albumin and BHBA levels were increased, whereas the BUN levels were decreased. There was a significant effect of the group × sex interaction on the serum AST levels. The total aerobic, total coliforms, and lactobacillus bacterial counts of the recto-anal swabs were not different between the experimental groups. In conclusion, the present data demonstrated that supplementation of pre-weaning calves’ milk with M. cordata at 1 g per day did not improve growth performance but changed their metabolic status.

Ảnh hưởng của chế phẩm lactozym đến cầu trùng, một số vi khuẩn và hình thái vi thể biểu mô đường ruột ở gà

This study is aimed to identify effect of lactozym supplementation on coccidae, some large intestinal bacterium counts and small intestinal epithelial villum measurements of chickens. A total of 900 chickens were separated into 2 groups, 450 chicks in each (chicks in the experimental group were supplemented lactozym in feed, in case of non-supplemented in control group, the experiment was replicated 3 times, with 150 chicks in each). The results demonstrated that the rate and intensity of coccidae in chicken supplemented lactozym group were lower as compared with the control group, especially in the period of > 4 - 8 and > 8 - 12 week-old (30.67 and 16.67%, respectively) in the experimetal group, while the control group was 38.67 and 20.00%, respectively. In summer, the rate of chicken coccidial infection was the highest (34.00% in experimental group and 40,67% in control group) and the lowest in winter (6,00% in experimental group and 17.33% in control group). Colon Escherichia coli, Salmonella, Clostridium perfringens and total aerobic bacterial counts were decreased by the probiotic administration. Jejunum villi height was increased while jejunum villi wideness was decreased in the chicken supplemented probiotic in the diet.

Quantification, Variability Assessment of Bacterial Pollution and Public Health Hazards Linked to Users of Automated Teller Machines in Ekpoma, Edo State-Nigeria

Raising number of mortals has used automated teller machines (ATMs) over the years, but little is known about their microbial colonization status. Based on this premise, we examined eight out of the nine commercial bank’s ATM in Ekpoma environs for quantification, variability assessment of the bacterial cross contamination and the likely health hazards linked to the users of such cash dispensing machines. A total number of sixteen (16) samples were acquired from eight different commercial banks ATM keypads and screens within the study area, using sterile swab sticks immersed in sterile normal saline. Samples were subsequently transferred to the laboratory section of the Department of Microbiology, Faculty of Life Sciences, Ambrose Alli University, Ekpoma for analyses using standard microbiological procedures for isolation, quantification and identification between the period of September to October 2019. Results showed that the total aerobic bacteria count, Staphylococcus aureus and coliforms counts on both the ATM keypads and Screens ranged from 9.0 × 103±2.65 cfu/m2 to 1.92 × 104±3.61 cfu/m2, 3.5 × 103±1.73 cfu/m2 to 9.8 × 103±4.58 cfu/m2 and 4.8 × 103±1.00 cfu/m2 to 1.08 × 104±2.00 cfu/m2 respectively. One-way Anova depicted a no significant difference (P ˃ 0.05) in the total aerobic bacterial plate count, Escherichia coli and Staphylococcus aureus counts in the various banks’ ATM keypads and screens in respectively of the facilities placement and the number of users. The bacteria implicated in this study were Escherichia coli, Bacillus spp, Klebsiella pnuemoniae, Staphylococcus aureus, Pseudomonas aeruginosa, Proteus spp and Coagulase negative Staphylococcus spp. The findings from this study reveals that high volume of bacterial pollution were detected on ATM hardware user interface which invariably necessitated the need for adequate personal hygiene by both the users and custodians of such machines with a view to reducing the likely hood of spreading contagious agents.

Identification and Anti-bacterial Testing of Staphylococcus aureus Isolated from Jollof Rice sold at selected Cafeterias in Federal University Dutse Campus, Jigawa State.

This research was aimed at identifying Staphylococcus aureus isolated from jollof rice samples at selected cafeterias in Federal University Dutse campus. A total of fifteen (15) samples were collected and processed within an hour in sterile containers from five (5) different cafeterias (A, B, C, D and E). The total aerobic bacterial counts recorded from samples A, B, C, D and E were 1.6 x 105, 1.1 x 105, 1.1 x 107, 9.3 x 104, 1.3 x107 cfu/g respectively while total Staphylococcal counts recorded from samples A, B, C, D and E were 1.3 x 104, 6.5 x 103, 6.0 x 105, 4.0 x 103, 1.5 x108 cfu/g respectively. Based on staphylococcal counts recorded, sample A result is unacceptable while samples B and D are within tolerable microbiological quality while that of samples C and E are also of poor quality. Staphylococcus aureus isolated from the samples was higher in samples C and E than in samples A, B and D. The isolate was susceptible to Ofloxacin and Gentamicin based on susceptibility tests conducted. Closer supervision of food handlers preparing and serving the food, most be carried out routinely by relevant authorities within the campus with a view to preventing possible outbreak of food borne illness caused by S. aureus.

Degradation Kinetics of Microbial Consortium Isolated from Diesel Oil Impacted Soil in Delta Park, University of Port Harcourt, Nigeria

Heavy-duty generators constitute a form of hydrocarbon pollution but enrich microorganisms to having degradative ability of hydrocarbons hence can be used for remediation. In this study a laboratory treatability (biodegradation screening) study was employed to investigate the hydrocarbon degradation competence of bacteria and fungi. Culture-dependent microbiological and physicochemical analyses was conducted on the soil samples obtained from the polluted site. The total aerobic heterotrophic bacterial and fungi counts increased from 5.0-7.5 (Log10 cfu/mL) between day 0-14 then reduced to 6.5 Log10 cfu/mL. The hydrocarbon-utilizing bacteria increased from 4.5-5.2 (Log10 cfu/mL). Percentage degradation hydrocarbons, attributed to fungi bacteria and bacteria/fungi consortia, were 42.3%, 54% and 70% respectively while the control had 6.0%. The total petroleum hydrocarbon (TPH) removal rate (K) was modelled using the first order kinetics: y=-0.0398x+9.79; K=0.0398d-1. These results, correspond to a degradation efficiency of 70% and t1/2 of 17 days for the bacterial/fungal consortium. The K values for the other setups were 0.019 d-1, 0.0261 d-1 and 0.0022 d-1 with the corresponding degradation efficiencies of 42%, 54% and 6.01% and half-life of 37 days, 27 days and 315 days for fungi, bacteria and control respectively. This result indicates that the use of microbial consortia has high potentials in remediation of hydrocarbons and other pollutants of concern.

High-Throughput 16S rRNA Sequencing to Assess Potentially Active Bacteria and Foodborne Pathogens: A Case Example in Ready-to-Eat Food

Technologies to detect the entire bacterial diversity spectra and foodborne pathogens in food represent a fundamental advantage in the control of foodborne illness. Here, we applied high-throughput 16S rRNA sequencing of amplicons obtained by PCR and RT-PCR from extracted DNA and RNA targeting the entire bacterial community and the active bacterial fraction present in some of the most consumed and distributed ready-to-eat (RTE) salad brands in Europe. Customer demands for RTE food are increasing worldwide along with the number of associated foodborne illness and outbreaks. The total aerobic bacterial count in the analyzed samples was in the range of 2–4 × 106 CFU/g (SD ± 1.54 × 106). Culture validated methods did not detect Salmonella spp., Escherichia coli, and other fecal coliforms. 16S rRNA gene Illumina next-generation sequencing (NGS) data were congruent with these culture-based results and confirmed that these and other well-known foodborne bacterial pathogens, such as Listeria, were not detected. However, the fine-resolution of the NGS method unveiled the presence of the opportunistic pathogens Aeromonas hydrophyla and Rahnella aquatilis (relative frequency of 1.33–7.33%) that were metabolically active in addition to non-pathogenic, active members of Yersinia spp. (relative frequency of 0.0015–0.003%). The common ail and foxA marker genes of Yersinia enterocolitica were not detected by qPCR. Finally, our NGS data identified to non-pathogenic Pseudomonas spp. as the most abundant and metabolically active bacteria in the analyzed RTE salads (53–75% of bacterial abundance). Our data demonstrate the power of sequencing, in parallel, both 16S rRNA and rDNA to identify and discriminate those potentially and metabolically active bacteria and pathogens to provide a more complete view that facilitates the control of foodborne diseases, although further work should be conducted to determine the sensitivity of this method for targeting bacteria

Dietary combination of chitosan nanoparticle and thymol affects feed utilization, digestive enzymes, antioxidant status, and intestinal morphology of Oreochromis niloticus

Currently, the use of phytogenic additives and nanoparticles formulation in fish diets raises great worldwide interest. However, studies on the outcomes of their combination in farmed fish feeding are scarce. Hence, an experiment was planned to examine the effect of chitosan nanoparticle (ChNP), thymol (THY) or their mixture (THY + ChNP) supplementation on growth, whole-body composition, hematological profile, biochemical parameters, intestinal bacterial count, digestive enzymes, and intestinal histomorphology of Oreochromis niloticus. Fish (4.97 ± 0.02 g) were randomly distributed into 4 different treatments. The control group was fed a basal diet, while the other three groups were fed diets supplemented with THY (0.5 g/kg diet), ChNP (5 g/kg diet), and THY + ChNP at the same levels. Results showed that interaction synergistic effect was apparent between the supplemented THY and ChNP on the enhancement of feed and protein utilization, lymphocyte count, HCT, MCV, and MCHC values together with catalase, lipase, and protease activities. The individual THYor ChNP addition to the fish diet significantly improved growth performance indicators, feed utilization, erythrogram profile, oxidative stress parameters, lipase enzyme activity, and lipid sedimentation. Intestinal villus length was significantly increased in ChNP and THY + ChNP supplemented groups. A significant drop of the total anaerobic and aerobic intestinal bacterial count was apparent in THY and ChNP supplemented groups. Conclusively, although the individual addition THY or ChNP improved growth and some health indications, a notable synergistic interaction was obvious following their co-addition in most indicators.

Cold plasma treatment induces phenolic accumulation and enhances antioxidant activity in fresh-cut pitaya (Hylocereus undatus) fruit

Non-thermal cold plasma as a novel method for maintaining safety and inducing phenolic accumulation in fresh-cut pitaya (Hylocereus undatus) fruit and the possible mechanisms were investigated. Results showed that cold plasma treatment (60 kV for 5 min) significantly inhibited the growth of total aerobic bacterial counts, increased the cutting-induced phenolic accumulation and enhanced antioxidant activity in fresh-cut pitaya fruit. Moreover, cold plasma treatment promoted the consumption of main sugars, enhanced the level of energy status, accelerated the generation of reactive oxygen species (ROS) at earlier storage, increased gene expression and activity of crucial enzymes in phenylpropanoid pathway. The present research provides convincing evidence regarding the beneficial effects of cold plasma treatment for inducing phenolic accumulation and enhancing antioxidant activity of fresh-cut pitaya fruit and offers potential opportunity for the processing and preservation of fresh-cut fruits and vegetables.

Microbiological quality assessment of herbal medicinal products and antibiotic resistance profile of bacteria

The microbiological quality of some herbal medicinal products available in Dhaka, Bangladesh was evaluated. In the studied samples, the total aerobic bacterial count (TABC) varied from 6.20 × 102 to 2.97 × 105 cfu /ml, total yeast and mold count ranged from 0 to 1.80 × 104 cfu /ml, total coliform count varied from 0 to 2.80×103 cfu/ml and total staphylococcal count (TSC) ranged from 0 to 2.30 × 104 cfu/ml. A strong positive correlation (r = 0.849) was observed between TABC and TSC. Out of 24 herbal medicinal samples examined, 5 (20.83%) did not comply with the microbiological criteria set by internationally recognized organizations. The study revealed that 100% of the Escherichia coli isolates were resistant to amoxicillin and penicillin G, 85.71% were resistant to nitrofurantoin and 71.43% were resistant to ceftriaxone and cefuroxime: and 57.14% were resistant to erythromycin. Among the Staphylococcus aureus isolates tested, 100% were resistant to amoxicillin, nalidixic acid and Penicillin G; whereas 33.33% showed resistance to cefuroxime.

Bacteriological Quality Assessment of Kilishi Produced in Kunchi Local Government Area, Kano State, Nigeria

Dried roasted sliced meat (Kilishi) is a popular meat product in Northern Nigeria that is relished locally and internationally. However, the abundance of a number of nutrients that favour the establishment, growth and proliferations of microorganisms, makes it a vehicle for transmitting food borne illness. This study was aimed at determining the microbiological quality of Kilishi in Kunchi Local Government Area, being one of the well-known Kilishi production town in Kano State. The experimental lay-out for the study was a completely randomised design in which a total of 15 freshly prepared Kilishi samples (100g each) were collected from three well known retail locations, identified as A (Malikawa Garu), B (Shuwaki) and C (Kunchi town), respectively. The samples were assessed for their microbiological quality according to standard procedures. Results for total aerobic mesophilic bacterial count (APC) cfu/g show Location A had 3.92×105cfu/g, Location B had 4.83×105cfu/g, Location C 5.43×105cfu/g. The results for the total coliform counts(TCCs) revealed30 MPN/g for Location A, 37 MPN/g for Location B and 50 MPN/g for Location C. Biochemical analysis confirmed the presence of Escherichia coli, Klebsiella specie, and Staphylococcus specie in all the three locations, while Enterobacter was detected in Location C. Our finding indicates serious contamination of kilishi products at retail outlets which could be of public health concern. Therefore, good production practices, packaging and storage were recommended.

Evaluation of Enrofloxacin for Use in Cryopreservation of Zebu Bull (Bos indicus) Semen.

Aim: The present study was designed to evaluate enrofloxacin (EN), a fluoroquinolone broad-spectrum antibacterial drug for use in cryopreservation of Zebu bull semen. Materials and Methods: Semen was collected from three Zebu bulls of the Sahiwal breed (Bos indicus) for 3 weeks (replicates) for each experiment. Experiment I: semen samples were cultured for isolation of bacteria and in vitro sensitivity tests against streptomycin, penicillin, and EN. Proteus spp., Pseudomonas aeruginosa, Staphylococcus aureus, and Escherichia coli were isolated. P. aeruginosa was found to be resistant to streptomycin and penicillin (SP), while Proteus spp. was resistant to streptomycin. EN effectively inhibited the growth of all four bacteria in an in vitro sensitivity test. Experiment II: in vitro dose toxicity of EN (0-2000 μg/mL) for bull sperm was assessed in 2.9% sodium citrate buffer. EN up to a concentration of 1200 μg/mL was found to be safe for motility and viability of bull spermatozoa. Experiment III: semen was cryopreserved in a tris-citric acid extender containing either SP or EN (400 μg/mL) or without antibiotics as the control. Results: Post-thaw sperm motility was found to be higher in the extender containing EN and SP compared to control. Nevertheless, sperm viability was recorded higher (p < 0.05) with EN compared to SP and control. Sperm chromatin integrity did not differ (p > 0.05) in EN, SP, and controls. The total aerobic bacterial count was recorded as zero in the extender containing EN compared to SP and control. The fertility rate was higher (p < 0.05) with 400 μg/mL EN (59%) compared to SP (44%). Conclusions: It is concluded that EN is capable of controlling the bacterial load in frozen Zebu bull semen, resulting in a higher fertility rate under field conditions.

Characterization of the physical, microbiological, and chemical properties of sonicated raw bovine milk

Innovative processing technologies, such as ultrasonication, can change the properties of milk, allowing for the improvement or development of dairy foods. Yet taking bench-scale equipment to pilot plant scale has been challenging. Raw milk, standardized to 3% fat and warmed to inlet temperatures of 42 or 54°C, was exposed to continuous, high-intensity, low-frequency ultrasonication (16/20 kHz, 1.36 kW/pass) at flow rates of 0.15, 0.30, and 0.45 L/min that resulted in resident times within the reaction cell of 6, 3, and 2 min per pass, respectively. Multiple passes (3, 5, and 7, respectively) were required to obtain a total exposure time of 14 to 18 min. Evaluation of fat droplet sizes, enzyme coagulation properties, and microstructure of milk and milk gels, as well as determining compositional and lipid properties, were conducted to determine the potential of the ultrasound system to effectively modify milk. Laser scanning particle sizing and confocal microscopy showed that the largest droplets (2.26 ± 0.13 µm) found in raw milk were selectively reduced in size with a concomitant increase in the number of submicron droplets (0.37 ± 0.06 µm), which occurred sooner when exposed to shorter bursts of ultrasonication (0.45 L/min flow rates) and at an inlet temperature of 54°C. Ultrasound processing with milk entering at 42°C resulted in faster gelling times and firmer curds at 30 min; however, extended processing at inlet temperature of 54°C reduced curd firmness and lengthened coagulation time. This showed that ultrasonication altered protein-protein and protein-lipid interactions, thus the strength of the enzyme-set curds. Scanning electron microscopy revealed a denser curd matrix with less continuous and more irregular shaped and clustered strands, whereas transmission electron microscopy showed submicron lipid droplets embedded within the protein strands of the curd matrix. Processing at inlet temperature of 54°C with flow rates of 0.30 and 0.45 L/min also reduced the total aerobic bacterial count by more than 1 log cfu/mL, and the number of psychrophiles below the limit of detection (10 cfu/mL) for this study. Ultrasonication exposures of 14 to 18 min had minimal effect on the milk composition, fatty acid profiles, and lipid heat capacity and enthalpy. The findings show that this continuous ultrasound system, which is conducive to commercial scale-up, modifies the physical and functional properties of milk under the parameters used in this study and has potential use in dairy processing.

Bacteriological profile, antimicrobial susceptibility patterns of the isolates among street vended foods and hygienic practice of vendors in Gondar town, Northwest Ethiopia: a cross sectional study

BackgroundThere are numerous advantages offered by street vended foods, but evidence exists that foods exposed for sale on the road side may be contaminated by pathogenic microorganisms. However, information on the bacteriological profile, bacterial load and antimicrobial susceptibility patterns of bacterial isolates from street food in Gondar town are lacking. The aim of this study was to assess bacterial profile, bacterial load, and antimicrobial susceptibility patterns of bacterial isolates among street vended foods and also the hygienic practice of vendors in Gondar town, Northwest Ethiopia.MethodsSocio-demographic characteristics and the hygienic practices of 24 vendors were collected using structured questionnaire. A total of 72 food samples from four different food items were analyzed and counted by standard aerobic plate count method. Ten grams of each food sample was transferred in to 90 ml of buffered peptone water and homogenized. The homogenates were serially dilute and a volume of 0.1 ml dilution was spread on solid media and incubated at 35-37 °C for 24 h. Antibiotic susceptibility testing was done for isolated species using Muller Hinton agar and data was entered and analyzed by using SPSS version 20.0.ResultsSeventy two food samples of street vended food were analysed for bacterial pathogens. 44/72 tested positive, a total of 63 isolates were identified as 19 samples contained two pathogens. The total mean aerobic bacterial count was 6.64 × 104 CFU/g which is varied from 1 × 104–1.86 × 105 CFU/g. S. aureus is the most frequent isolate 34 (53.96%) followed by E.coli 15(23.8%), Enterobacter species 10(15.87%) and Citrobacter species 4(6.3%). Gentamycin, chloramphenicol, tetracycline, ciprofloxacin, and trimethoprim-sulfamethoxazole were found to be the most effective antimicrobials against all isolates but the enterobactereaceae were resistant to ampicillin and Ceftaziidime and S.aureus were resistant to penicillin.ConclusionThe results of this study showed that, the majority of street-vended food items in Gondar were contaminated with one or more different pathogenic bacteria. The presence of these bacteria in foods could lead to potential health problems for consumers. Therefore, health education as well as training in food safety and hygienic handling is required for food handlers to minimize contamination and the likelihood of people falling ill.

The Impact of Diets Supplemented with Different Forms of Rosemary and BHA on Chemical, Microbial and Sensory Properties of Rainbow Trout Fillet

ABSTRACTThe objective of this study was to evaluate the effect of different forms and doses of rosemary on chemical, microbial, and sensory properties of rainbow trout fed nine different diets: control (C), 20 g.kg−1 rosemary powder (20RP), 40 g.kg−1 rosemary powder (40RP), 0.3 g.kg−1 rosemary extract (0.3RE), 0.6 g.kg−1 rosemary extract (0.6RE), 0.15 g.kg−1 rosemary nanopowder (0.15RNP), 0.3 g.kg−1 rosemary nanopowder (0.3RNP), 0.15 g.kg−1 butylated hydroxyanisole (BHA) (0.15BHA), and 0.3 g.kg−1 BHA (0.3BHA). After 8 weeks’ feeding, the fish fillets were sampled on the 1st, 4th, 8th, 12th, and 16th days and then stored on 4°C. Lower value of pH, peroxide value (PV), total volatile base nitrogen (TVB-N), free fatty acids (FFA), and thiobarbituric acid (TBA) were reported in fish fed with RP, RE, RNP, and BHA; among them, RNP groups had the lowest properties (p < 0.05). Furthermore, lower total viable aerobic bacterial counts (TVC) and psychotropic counts (PTC) were observed in the fillets of the fish fed with rosemary treatments, especially in RNP treatments (7.52–9.41 log10 CFU.g−1), along with a slower spoilage in terms of sensory factors (texture, color, odor, and overall) on the 16th day. Finally, use of natural antioxidant nanorosemary in the diet may positively affect fish fillet quality and delay post-mortem deterioration.

Storage Stability of Vacuum-packaged Dry-aged Beef during Refrigeration at 4°C.

Although the production of dry-aged beef has been increasing, most purveyors are unaware of the changes in quality that ensue after completion of the aging period and do not adhere to specific guidelines for its packaging and storage. The objective of this study was to investigate the storage stability of vacuum-packaged dry-aged beef based on changes in microbial, physicochemical, and sensory properties during refrigeration at 4°C for 21 d. The total aerobic bacterial count exceeded 6 Log CFU/g at approximately day 11 and significantly increased after day 14. Freshness indicators such as pH and volatile basic nitrogen content were acceptable until day 14 and 21, respectively. Based on the evaluation of overall sensory acceptability, the dry-aged beef was acceptable until 14 d without any sensory deterioration. Therefore, vacuum-packaged dry-aged beef could be stored for 11 d at 4°C without any adverse effect on its microbial and sensory quality.

Assessment of food microbiological indicators applied on poultry carcasses by culture combined MALDI-TOF MS identification and 16S rRNA amplicon sequencing

Examination of the bacterial contamination on food products is still largely performed by standardized culture methods, though culture-independent methods are suggested as a more reliable approach. Knowledge of the diversity of bacteria isolated from food as well as the impact of the plate incubation conditions applied are still understudied. The impact of incubation at 7 °C and 30 °C on total aerobic bacterial count and diversity, and the performance of ISO methods generally applied in microbiological quality examination were assessed by culture combined MALDI-TOF MS identification and 16S rRNA amplicon sequencing. Examining breast skin of 16 chicken carcasses, no significant impact of the incubation temperature on the total aerobic bacteria level and diversity was detected, limiting the usefulness of additional psychrophilic examination. Bacteria phenotypically similar to Pseudomonas, were identified on selective CFC plates, and on MRS agar plates for lactic acid bacteria, Escherichia coli and Staphylococcus were commonly present. Application of 16S rRNA amplicon sequencing revealed a higher bacterial diversity, but the impact of the DNA extraction kit applied, and the detection of non-viable bacteria should be taken into account to interpret the final outcome.

The Effects of a Synbiotic Mixture of Galacto-Oligosaccharides and Bacillus Strains in Caspian Salmon, Salmo trutta caspius Fingerlings.

The effect of dietary supplementation with a synbiotic mixture of galacto-oligosaccharides (GOS) and Bacillus spp. was examined in Caspian salmon, Salmo trutta caspius (Kessler, 1877) fingerlings. Caspian salmon fed with the synbiotic diet had significantly higher weight gain rate, protein efficiency ratio, and survival rate, as well as lower feed conversion ratio, compared to the control group (P < 0.05). The serum protein, albumin, globulin, and lactate dehydrogenase levels of the fish fed with the synbiotic diet were significantly higher than the control group (P < 0.05), while the serum alkaline phosphatase levels were significantly lower (P < 0.05). The activities of the innate immune response parameters, including lysozyme, superoxide dismutase, and catalase were significantly higher in the Caspian salmon fed with the synbiotic diet (P < 0.05). The gut microbiota of the Caspian salmon fed with the synbiotic diet contained significantly elevated total viable aerobic bacterial counts (TVABCs), lactic acid bacteria (LAB) levels, and LAB/TVABCs ratio (P < 0.05). Additionally, the gut activities of amylase, trypsin, and chymotrypsin in the gut, as well as the trypsin/chymotrypsin ratio, were significantly increased in the fish that received the synbiotic diet (P < 0.05). In conclusion, the combined GOS and Bacillus spp. supplement positively affected the growth, survival rate, immunobiochemical parameters, digestive activity, and beneficial microbial density in the gut of Caspian salmon fingerlings.

Effects of infrared radiation combined with heating on grape seeds and oil quality.

The objective of this work was to determine the effects of infrared radiation combined with heating on grape seeds and oil quality. Experimental results showed that high moisture removal was achieved through infrared radiation heating. After infrared radiation heating for 108 s, the inactivation rates of total aerobic bacterial and total mold-yeast counts of the grape seeds were 1.97 ± 0.12 and 0.62 ± 0.09 log CFU/g, respectively. The maximum microbial reduction was achieved after infrared radiation heating of the grape seeds to 135 ℃ and subsequent holding at 75 ℃ for 60 min. The crude oil yield of samples subjected to these conditions was 10.39%, which was significantly higher ( p < 0.05) than that of the control sample, and their final moisture content was 7.20%. Additionally, increases in the free fatty acid content and peroxide value of the oil were achieved. The iodine value of the oil decreased. In conclusion, surface pasteurization with a high oil yield could be achieved by the combination of infrared radiation heating and the holding process. Consequently, infrared radiation treatment is suggested to be a promising method for the surface pasteurization of grape seeds.