Plate Mold Research Articles

Microbial Quality of Home Prepared Complementary Foods in Slum Households with Children of Age 6-24 Months in Addis Ababa: A Community Based Cross-sectional Study

Background: Foodborne disease is a worldwide challenge. It causes a huge burden of diarrhea in children mostly in developing countries and this is common during the complementary feeding periods. As home serve as the proliferation ground for microbial pathogens, home- prepared complementary foods, coupled with unhygienic feeding practice and contamination, it is the cause of child morbidity and poor nutritional status. This is worse in slum households. However, recent evidence is very scarce and further study is very necessary. Objective: To investigate the microbiological quality of home-prepared complementary foods in slum households with children of 6-24 months in Addis Ababa, 2021. Methods: A community-based cross-sectional study design was used and a total of 91 households were included. Three sub-cities in Addis Ababa and slum settlements within each sub-city were randomly selected by lottery method. Households with children of age from 6-24 months were selected by systematic random sampling. Laboratory investigation was used for microbial identification and excel sheet was used for data entry and cleaning. SPSS V. 23 was used for data analysis. Result: The median and interquartile range of aerobic plate count, S.aureus, yeast, molds and total coliforms are log5.75cfu/ml, Log1.84cfu/ml; Log4.7cfu/ml, Log5.46cfu/ml; Log5.29 cfu/ml, Log3.68cfu/ml; Log4.17cfu/ml, Log4.70cfu/ml; and Log0, Log3.5cfu/ml, respectively. Fecal coliform and E.coli were observed in 19% and 10% of complementary food samples. Conclusion: The load of aerobic plate count, S.aureus, yeast, molds, and total coliform are high in samples of complementary foods. Therefore, intervention studies for further identification of contamination sources should be made in order to minimize contamination of complementary foods and associated infections.

Post-drying decontamination of laver by dielectric barrier discharge plasma, UV radiation, ozonation, and hot air treatments

While dried laver serves as an important raw ingredient for seaweed snacks, the microbial quality and safety risks associated with the preparation and processing of dried laver have not been well studied. In this project, three commercial laver processing plants were sampled from 2020 to 2022. Results indicated that the current washing and two-step drying process increased the microbial loads in dried laver. The total aerobic plate count (APC), coliform, and mold counts in dried laver ranged from 7.34 to 7.91, 2.12 to 3.87, and 1.65 to 3.87 Log CFU/g respectively. The study further explored the decontamination efficacy of four post-drying treatments (three non-thermal and one thermal treatments). Dielectric barrier discharge (DBD) plasma (150 kV, 10 min), UV-C radiation (40 cm, 30 min), ozone (150 ppm, 40 min), and hot air (150 °C, 30 min) reduced the APC and coliform levels by 2.10 and ∼1.12, 0.98 and 1.03, 2.12 and ∼2.87, and 3.00 and 2.24 Log CFU/g respectively. Unfortunately, Ozone and hot air treatments led to significant color change and nutrient losses. Microorganisms become harder to control once dried on food, future study should explore the use of pre-drying treatments to better enhance the microbial quality and safety of dried laver.

Processing methods for conductive polymer composite bipolar plates: Effect on plate quality and performance

AbstractConductive polymer composites (CPCs) have been identified as viable replacements for graphite and metals for polymer electrolyte membrane fuel cell (PEMFC) bipolar plates (BPs). One important factor, apart from composite formulation, that affects the quality and properties of CPC BPs is the processing route. Therefore, understanding the possible processing methods for different matrix–filler combinations and their effects on the quality and properties of the plates can help in controlling and improving the final performance of BPs. This paper reviews the blending and molding techniques for CPC BPs, with a focus on relationship between formulation and processing method. The effects of processing route and conditions on microstructural features of CPC BPs, which affect the performance of the plates are also discussed. Finally, directions for further studies with potential to advance the development of quality and high‐performance CPC BPs are highlighted. Identified key areas for further research include control of filler orientation to improve through‐plane conductivity, correlation between processing parameters and dimensional accuracy of molded plates, and additive manufacturing of composite BPs.

Effect of Hot Air Heating on The Cavity Temperature Distribution of Injection Mold

In this paper, the air-assisted mold temperature control (AMTC) is applied for heating the mold in the injection molding process. The simulation is run with the same boundary conditions in the experiment. The results shows that the AMTC can heat the surface mold plate to 171.6 °C. This temperature value is higher than the glass transition temperature of almost thermoplastic materials that used in the injection molding process. With the product thickness values of 0.1 mm, 0.3 mm and 0.5 mm, the heating rates were 6.3 °C/s, 6.39 °C/s and 6.58 °C/s, respectively. The increase in heating rate can be explained by the need for thermal energy to heat up the stamp volume that is inserted in the mold cavity for changing the product thickness. Also, the highest temperature at the top of the stamp which is nearest to the hot air gate, and the temperature is smaller when the area is far from the hot air gate.

Influence of Polyvinylpyrrolidone on Thermoelectric Properties of Melt-Mixed Polymer/Carbon Nanotube Composites.

For thermoelectric applications, both p- and n-type semi-conductive materials are combined. In melt-mixed composites based on thermoplastic polymers and carbon nanotubes, usually the p-type with a positive Seebeck coefficient (S) is present. One way to produce composites with a negative Seebeck coefficient is to add further additives. In the present study, for the first time, the combination of single-walled carbon nanotubes (SWCNTs) with polyvinylpyrrolidone (PVP) in melt-mixed composites is investigated. Polycarbonate (PC), poly(butylene terephthalate) (PBT), and poly(ether ether ketone) (PEEK) filled with SWCNTs and PVP were melt-mixed in small scales and thermoelectric properties of compression moulded plates were studied. It could be shown that a switch in the S-value from positive to negative values was only possible for PC composites. The addition of 5 wt% PVP shifted the S-value from 37.8 µV/K to -31.5 µV/K (2 wt% SWCNT). For PBT as a matrix, a decrease in the Seebeck coefficient from 59.4 µV/K to 8.0 µV/K (8 wt% PVP, 2 wt% SWCNT) could be found. In PEEK-based composites, the S-value increased slightly with the PVP content from 48.0 µV/K up to 54.3 µV/K (3 wt% PVP, 1 wt% SWCNT). In addition, the long-term stability of the composites was studied. Unfortunately, the achieved properties were not stable over a storage time of 6 or 18 months. Thus, in summary, PVP is not suitable for producing long-term stable, melt-mixed n-type SWCNT composites.

PHYSICOCHEMICAL, PHYTOCHEMICAL, AND EVALUATION ANGIOTENSIN-CONVERTING ENZYME INHIBITORY ACTIVITY OF TAMOENJU (Hibiscus surattensis L.) LEAVES EXTRACT

Tamoenju (Hibiscus surattensis L.) is one of the ethnomedicinal plants used in treating hypertension. One of the potential antihypertensive mechanisms includes angiotensin-converting enzyme ACE inhibitors, considered the firstchoice treatment for hypertension. This research presents a physicochemical, phytochemical, and ACE inhibitory activity test of tamoenju leaf extract (TLE). The leaf extract was evaluated to determine the physicochemical and phytochemical profiles using standard methods. The physicochemical evaluation indicated 20.66 ± 3.51% water content, 26.67±5.77% drying shrinkage, 2.0 ± 1.0% total ash value, 0.30 ± 0.13% acid insoluble ash value, 20.00 ± 4.00% water soluble extractive value, 57.00 ± 4.61% alcohol soluble extractive value, and 0.89±0.01 g/ml specific gravity extract. The total plate and yeast mold numbers were 15x103 CFU/g and 92 x 10 CFU/g, respectively. The results of metal contamination showed Pb 1.05 ± 0.15 mg/kg and Cd 0.14 mg/kg. The phytochemical evaluation revealed the presence of tannins (69.02%), flavonoids (27.63%), alkaloids (14.18%), saponins (2.12%), and steroids (1.06%). ACE inhibitory activity was tested and obtained at 38.50±1.41 µg/mL for TLE and 9.44±0.58 µg/mL for captopril. Based on the research results, TLE qualifies as a standardized extract and can be used as a reference for developing herbal medicines. Tamoenju leaves extract is quite high as a natural ACE inhibitor and has the potential as an antihypertensive.

Development of cheese spread using goat milk Chakka and Guava (Psidium guajava) fruit pulp

A study was conducted to develop cheese spread from cheddar cheese (CC), goat milk chakka (GMC) and guava fruit pulp (GFP). The proportion of CC and GMC were chosen based on preliminarily trial. Subsequently, GFP (Sardar and Basti Red varieties of guava) was incorporated @ 5% of cheese spread. With the increased level of GMC in cheese spread, fat, protein, ash and total solids contents decreased and acidity increased (P<0.05) significantly. Colour values (L* and a*) increased whereas b* decreased (P<0.05) significantly with increased level of GMC. Colour and appearance, flavour, body and texture, spreadability and overall acceptability in optimized cheese spread were 8.50±0.40, 8.66±0.02, 7.80±0.05, 7.73±0.10 and 8.23±0.05 scores, respectively. With the increased level of GFP in cheese spread, carbohydrate, ash, and total solids increased while fat and protein decreased. Fat, protein, carbohydrates, ash, total solids, acidity and vitamin C contents in optimized cheese spread were 19.47±0.04, 21.53±0.07, 3.01±0.01, 2.15±0.13, 46.18±0.11, 1.92% lactic acid and 12.73 mg/100 g, respectively. Microbial load in terms of standard plate count, and yeast and mould counts increased with increasing GFP levels in cheese spread. It was concluded that best quality cheese spread could be prepared by blending CC and GMC at 40:60 with 6% GFP of Sardar variety.

Quality of Tomato Juice as Influenced by Non-Thermal Air Plasma Treatment

This paper presents the results of an experiment based on using a Glide-arc type plasma reactor operating at atmospheric pressure for the quality of fresh pressed tomato juice, variety Bekas. The impact of after-glow plasma gas (air) on the physicochemical, microbiological properties and morphology of the product’s samples was investigated. Five groups of juices characterized by different exposure times (30, 60, 120, 300 and 600 s), as well as untreated juice (as control) were used. The juice quality was assessed on days 1, 3, 5, and 10 of refrigerated storage. Significant increases were observed when Cold Atmospheric Plasma (CAP)-treated tomato juice was tested against total soluble solids, pH, lycopene, and vitamin C in comparison to the control treatments. Moreover, changes in the tested physicochemical values during the storage of juice subjected to the action of cold plasma did not progress as quickly as in the case of the control juice. A significant decrease was observed in total plate count, yeast, and mold after 300–600 s CAP treatment. The findings of the current study suggested that CAP treatment is a promising technique that could provide improved quality and stability during the processing of tomato juice with better physicochemical properties and bioavailable nutrients.

Optimization of continuous flow pulsed light system process parameters for microbial inactivation in tender coconut water, pineapple and orange juice

AbstractContinuous flow pulsed light (PL) system was designed and fabricated with a residence time of 3.5 s at a flow rate of 100 ml/min to study the effect on microbial quality of the fruit juice. The circuit was designed to deliver pulse energy between 12.6 and 756 J/cm2 with a flash lasted 360 μs at a frequency of three pulses per second. Tender coconut water, pineapple and orange juice was treated with different input voltage (500–1000 V) to the lamp, distance of the lamp exposed to the sample (5–15 cm) and treatment time (15–45 s) to reduce the population of aerobic plate count (APC), yeast and mold. Box–Behnken design (BBD) was used to optimize the PL process parameters. The process condition was optimized based on the microbial reduction rate. The optimized condition was input voltage of 1492, 1499, and 1486 V, distance of 7.6, 10.2, and 5.3 cm, and treatment time of 43 s (12 passes), 44 s (13 passes), and 45 s (13 passes) for tender coconut water, pineapple and orange juice, respectively at the target of five log reduction for APC and four log reduction for Y&amp;M. These results recommend that a continuous flow PL system could improve the microbial safety of the fruit juice. PL is a nonthermal method for inactivating food microbes, extending food's shelf life. For industrial purposes, the batch system is virtually impossible. As a result, continuous flow systems for liquid foods can provide a better way to handle large volumes. The optimized setup was found to achieve a microbial death rate of at least 5 log CFU/ml, consistent with FDA guidelines for fruit juice. The BBD of response surface methodology helps in optimizing the process parameters such as input voltage of the lamp, distance of the PL lamp to treatment tube and treatment time. The resulting mathematical model provides the PL process conditions for designing the equipment for different fruit beverages to obtain microbiologically safe products.

Microbial characterization of discarded breads

Bread is one of the most wasted products in distribution systems and in households. To consider reusing it, the presence of microorganisms must be taken into account. In this study, the microbial load of crumb and crust of four kinds of bread, sold in two different types of establishments, has been compared separately. Counts of Bacillus spp, sulphite reducing bacteria, coliforms, E. coli, Salmonella spp, lactic acid bacteria, Aerobic plate count, molds, and yeasts were determined. The microorganisms found were identified. The microbial load of discarded breads was similar to that of cereal flours found in other studies. In general, a greater presence of bacteria in breads from small stores than in those from supermarkets has been found. Some of the least sold breads in small bakeries, such as wholemeal or candeal, presented a higher microbial load. Although their quantity or type are not a concern for people's health, good practices must be implemented to reduce health risks in products made from discarded bread.

Cause analysis of stamping cracking and concealed cracking of tailgate inner plate

With the development of automobiles toward lightweight and comfort, the production of auto parts has higher and higher requirements for stamping materials and parts forming quality. During the stamping and manufacturing process of the passenger car tailgate inner plate, the tailgate inner plate has many cracks, concealed cracks, and other defects. In this paper, the fracture morphology of the defect section was observed, and the composition and mechanical properties were measured. At the same time, the production process of the steel plate and the working condition of the stamping die were analyzed. The results show that the cracking and concealed cracking defects of stamping sheets are mainly caused by the inclusion of die and sheet. Through the adjustment of the plate production process and mold, the cracking and concealed cracking defects disappeared. This work also provides a reference for the solution to stamping cracking defects in the future.

The impact of ozonation on the physicochemical properties, antioxidant potential and shelf life of Kinnow (Citrus Reticulata Blanco) juice

ABSTRACT Consumer demand for higher-quality fruit juices has resulted in the development of non-thermal processing to extend the shelf life of fruit juices. Ozonation is a novel technique, involving the production of volatile oxygen atoms capable of destroying an extensive range of microorganisms and lengthening the shelf stability of fruit juices. The purpose of this research was to examine the influence of ozonation on the physicochemical, bioactive components, and microbial properties of kinnow juice. Kinnow juice was exposed to ozone gas with fixed concentration 150 mg/h for 5, 10, and 15 minutes. Then, kinnow juice was filled in a plastic bottle and kept at 4 ± 2°C for 3 months. The mentioned parameters were examined after 30 days, 60 days, and 90 days. It was found that ozonation had shown a significant influence on nutritional characteristics of kinnow juice as it increased (p ≤ .05) the acidity, total soluble content, total phenolics content, flavonoids content, and antioxidant potential of kinnow juice and diminished the microbial activity, increasing ozone time from 5 to 15 minutes. OZ-15 (15 minutes of ozonation) showed the maximum value of total soluble content (14.70 ± 0.10 °Brix), titrable acidity (0.179 ± 0.10%), total flavonoid content (244.44 ± 3.70 mg equivalent of catechin/100 mL), and total antioxidant activity (305.95 ± 2.70 µg/g equivalent of ascorbic acid of juice), but it presented the least total mold counts (1.49 ± 0.02 colony forming unit/mL) and plate counts (1.53 ± 0.03 colony forming unit/mL). It was suggested that the ozonation could be used as an alternative to the traditional pasteurization and chemical preservatives on kinnow juice to retain quality characteristics.

Assessment of microbiological quality of dried vegetables marketed in Vhembe district, South Africa

Fruits and vegetables are important sources of nutrients and are included as part of healthy and balanced diet globally. Contamination of these commodities with pathogens during growth, harvesting, storage, transportation, processing and handling might occur. However, some of the pathogens are originated from human, animal or environmental sources. This study was conducted in order investigate the microbiological quality of sixty (60) different types of dried vegetable (pumpkin flower, leaves and cowpea leaves) samples that were purchased from various street vendors around Vhembe district municipality, Limpopo Province, South Africa. Five (5) different locations were identified, and twenty (20) samples of each dried vegetables were randomly collected. Microbiological analyses were conducted for coliform bacteria, Escherichia coli, Salmonella species, Bacillus cereus, total plate count, yeasts and moulds. Data analyses were conducted using SPSS version 25. Coliform counts were present in all dried vegetables samples ranging from 0.00 - 3.70 log10cfu/g. Escherichia coli counts ranged from 0.00 - 4.62 log10 cfu/g. Salmonella spp. varied from 0.00 - 3.75 log10 cfu/g. Bacillus cereus ranged from 0.00 - 3.72 log10 cfu/g. Total plate count ranged from 2.13 - 2.66 log10 cfu/g. Yeast counts ranged from 2.03 - 5.61 log10 cfu/g. However, mould counts did not grow after incubation for the dried vegetable samples. Most of the microbiological results were in line with the Food and Drug Administration standards of Philippines and Department of Health of South Africa. The study showed that most dried vegetable samples were safe for human consumption which means that good hygiene practices were properly implemented by street vendors However, there is a need for food scientist, policy makers and government officials to train street vendors on how to handle their food products as most of them are sold uncovered which lead to high microbial growth. The aim of the study was to assess the microbiological quality of dried vegetables such as pumpkin flowers (Cucurbita moschata Duchesne), pumpkin leaves (Cucrbita pep L.) and cowpea leaves (Vigna sinensis) sold in Vhembe district municipality. Key words: microbial quality, dried vegetables, foodborne pathogens, microorganisms, food safety

Improvement of the shelf life of grey mullet (Mugil cephalus) fish steaks using edible coatings containing chitosan, nanochitosan, and clove oil during refrigerated storage

The effects of edible coatings made of chitosan, or chitosan nanoparticles, and their combinations with clove oil on the physical, chemical, microbiological, and sensory properties of grey mullet (Mugil cephalus) steaks during refrigerated storage (4 °C) for 24 days were evaluated. The data indicated that metrics for all of these characteristics were improved significantly (P ≤ 0.05) in coated fish steak samples compared to the control sample. The coated steaks texture values were higher than those of control sample through storage time with nanochitosan coating containing clove oil having best value 2.51 kg/cm2 among tested samples at the end of storage period. However, pH values of coated samples were lower, a good indicator, than corresponding one of the control (6.46) with nanochitosan coatings with or without clove oil showed low mean values (6.11–6.13). Similar trend regarding chemical indices, i.e. total volatile basic-nitrogen, trimethylamine, peroxide, and thiobarbituric acid reactive substances values for samples coated with nanochitosan with or without clove oil giving better lower values than control or other treatments. Also, the coating delayed microbial (aerobic plate count, psychrotrophic bacteria, yeasts and molds, and total coliform bacteria) growth during the refrigeration storage period, and coated samples produced better results compared to the control sample. Sensory evaluations showed that the treatment enhanced the scores of fish steak samples compared to the control. The results showed that a nanochitosan coating with clove oil was the best treatment prolonged the shelf life of mullet steaks and efficiently maintained the quality attributes to an acceptable level during refrigerated storage for 24 days. Thus, these findings can be bases for producer to provide consumers with fresh fish steaks with good shelf life at refrigerated temperature for up to 24 days.Graphical

A Numerical Study on Increasing the Cavity Temperature in Injection Molds

In the injection molding process, the filling process will be easier and, in most cases, the surface quality will be significantly improved if the mold surface temperature is high. However, as the temperature of the mold plates rises, the cooling process takes longer, the injection molding cycle takes longer, and the cost of production rises. The most important thing is to keep the mold temperature under control, which means heating the mold surface to the required temperature while keeping the injection cycle time to a minimum. In this research, hot air was used as the heat source for raising the cavity temperature to over 200 °C with a heating time of 20 s. At the end of heating process, the temperature was collected at 10 points for comparison. In addition, the temperature distribution was also discussed.

Screening of Essential Oils and Effect of a Chitosan-Based Edible Coating Containing Cinnamon Oil on the Quality and Microbial Safety of Fresh-Cut Potatoes

Fresh-cut potatoes (Solanum tuberosum L.) are a popular food owing to their freshness, convenience, and health benefits. However, they might present a potentially high health risk to consumers during transportation, processing, and marketing. In the current study, 18 essential oils (EOs) were screened to test their antimicrobial activity against Listeria monocytogenes (LM), Salmonella typhimurium (ST), Staphylococcus aureus (SA), and Escherichia coli O157:H7 (EC O157:H7). The antibacterial effectiveness of a chitosan edible coating (EC) containing cinnamon oil was evaluated against microorganisms on fresh-cut potatoes. Fresh-cut potatoes were treated with chitosan EC and chitosan EC containing different concentrations (0, 0.2, 0.4, and 0.6%, v/v) of cinnamon oil, and uncoated samples served as the control. The viability of naturally occurring microorganisms and artificially inoculated LM on fresh-cut potatoes was evaluated, as were the colour, weight loss, and firmness of potatoes, every 4 days for a total of 16 days at 4 °C. The results demonstrate that the inhibition zones of cinnamon, oregano, and pomelo oils were 16.33–30.47 mm, 22.01–31.31 mm, and 21.75–35.18 mm, respectively. The cinnamon oil exhibits the lowest MIC (0.313 μL/mL) for four foodborne pathogens compared with oregano and pomelo oils. The chitosan EC containing 0.2% cinnamon oil effectively maintains the quality of fresh-cut potatoes including inhibiting the browning, preventing the weight loss, and maintaining the firmness. The decline of total plate counts, yeast and mould counts, total coliform counts, lactic acid bacteria count, and Listeria monocytogenes in EC containing 0.2% cinnamon oil were 2.14, 1.92, 0.98, 0.73, and 1.94 log cfu/g, respectively. Therefore, the use of chitosan EC containing cinnamon oil might be a promising approach for the preservation of fresh-cut potatoes.

On fatigue crack growth testing and analysis of non-crystallising rubber using planar tension specimen

Rubber fatigue crack growth tests are one method of characterising fatigue behaviour. Due to the possibility of using one specimen to measure fatigue at multiple load levels, it is often considered a faster and less expensive method compared to the time-consuming fatigue crack initiation tests. In this work, the possibility of a new specimen grip geometry for crack growth tests was investigated, enabling the use of specimens cut from compression moulded plates. Several variations of a crack growth predictor parameter for tests with different mean strain levels were investigated. In addition, the optimum variation of the crack growth angle with respect to the loading direction was evaluated using test measurements. The results show that the use of the simplified crack growth predictor can provide the same results as the commonly used tearing energy. Using the Euclidean length of the crack growth increments gives better results than their horizontal projection, with the possibility of using angle deviations up to 90° without major drawbacks.

Effect of hydrogen pressure on hydrogenation and pulverization behavior of Sm(CoFeCuZr)z ingot and strip casting flake

Effect of hydrogen pressure on hydrogenation and pulverization behavior of Sm(CoFeCuZr)7.6 alloy prepared by plate mold (PM) and strip casting (SC) has been systematically investigated. Increasing hydrogen pressure can improve the hydrogenation ability. Both the PM and SC have the similar hydrogen absorption process, which can be divided into two stages. The first stage follows the Sieverts’ law (1–5 MPa) while the second one deviates from the Sieverts’ law (5–10 MPa). Rietveld refinement shows that the hydrogen absorption causes different lattice distortion of different phases without changing the phase structure. The internal stress caused by such lattice distortion is the primary reason that accelerates the pulverization of the alloys, and increasing hydrogen pressure can lead to the decrease of particle size of the PM and SC alloys. The hydrogen decrepitation (HD) process are studied in detail based on these results. The hydrogen absorption mechanism of Sm(CoFeCuZr)7.6 alloy can be regarded as a hydrogen dissolution process without phase transformation. In addition, the existence of a large amount of fine grains in the SC has an adverse effect on the alignment, which can be optimized by taking effective methods to reduce the overcooling rate. This work proves that the SC, HD and jet milling process can be a promising new approach to powder preparation for high-performance Sm(CoFeCuZr)z sintered magnets.

Critical Study on Vital Factors Influencing Productivity Improvement

Abstract: In the press moulding process, the challenging task is to increase the productivity cycle of the product with zero rejection. Major problems involved in this process are the consumption of time and deduction of temperature for the loading and unloading process of the material in the mould plate. It is recommended to preheat the mould plate to a certain limit so that the temperature needed while processing is obtained in a shorter span of time. To overcome the time consumption problem, the mould plate should be mounted in a shorter interval of time todecrease the raw material loading time process. In this case, it helps to uplift the productiveness and leads us to a zero rejection rate

Antimicrobial Effects of Selenium and Chitosan Nanoparticles on Raw Milk and Kareish Cheese

The contamination of milk and its dairy products with different microorganisms could cause public health hazards. Antibacterial nanoparticles (NPs) are a novel way to ensure that milk and milk products are safe. The present study investigated the effect of chitosan NPs (CS-NPs) and selenium NPs (Se-NPs) on some microorganisms, which consequently affect raw milk and Kareish cheese. Small-sized nanomaterials of Se-NPs and CS-NPs at the size of approximately 20 nm were used in this study. The samples were 700 ml raw milk and 700g Kareish cheese manufactured from 3000 mg milk. The concentrations of used nanoparticles were 0.5%, 1%, and 1.5% for Se-NPs and 2.5%, 5%, and 10% for CS-NPs. They were used to improve the microbial properties of milk and Kareish cheese samples during storage at the refrigerated temperature of 4°C. The aerobic plate count, Enterobacteriaceae count, Staphylococcus count, and mold count were significantly reduced in milk and Kareish cheese samples treated with CS-NPs and Se-NPs. The study has confirmed that CS-NPs and Se-NPs indicated high antimicrobial activity against the studied microorganisms at all concentrations although CS-NPs were more effective than Se-NPs. It can be concluded that these NPs can be used as preservatives in milk and milk products, such as Kareish cheese. In addition, increasing the concentrations of these NPs by 10% for CS-NPS and 1.5% for Se-NPS boosted their effects.