Milk Processing Research Articles

Co-occurrence of simultaneous carbon and nitrogen removal and in-situ sludge separation in a novel single unit combined airlift bioreactor (CALBR) for milk processing wastewater treatment

Combined anaerobic-aerobic bioreactors offer considerable potential for treating different industrial wastewaters. However, difficulty in maintaining a stable coexistence of anaerobic, anoxic, and aerobic microbial communities and the necessity of space-consuming external settlers remain as crucial drawbacks associated with these systems. In this study, an innovative single stage combined airlift bioreactor (CALBR) comprising multiple bioreactors (anaerobic/anoxic/aerobic) and an internal settler (a rotating spiral separator for in-situ separation of biomass) was exploited to achieve simultaneous carbon and nitrogen removal from milk processing wastewater (MPW). Results demonstrated that the anaerobic pre-treatment zone made a substantial contribution towards COD and TN removal. Successful biomass separation and high effluent quality revealed that the rotating spiral separator can be used as a coupled clarifier to sustain higher biomass concentration through boosting the sludge compressibility and settleability which further upgrades the overall treatment bioprocess. sCOD removal, TN removal, SVI, and effluent turbidity of ˃96%, ˃75%, ˂90 mL/g, and ˂10 NTU were reached, respectively under optimum condition. The outcomes suggested that the novel CALBR is a promising technology which has a great potential to be transferred into practical implementation for high-rate combined biological wastewater treatment and sludge separation.

Chlorate and Trichloromethane Residues in Bulk Tank Milk Produced in the Republic of Ireland before and after Chlorine was Prohibited as a Cleaning Agent on Farms

In an effort to reduce the occurrence of chlorine derived residues such as chlorate and trichloromethane (TCM) in milk and ultimately in dairy products, ‘chlorine-free’ cleaning of milking equipment became compulsory in the Republic of Ireland (ROI) from January 2021. While data exists on TCM levels in bulk tank milk, little is known about the prominence and typical levels (mg/kg) of chlorate residue in bulk tank milk. To address this, 3625 bulk milk samples were collected from six milk processors and were analysed for chlorate and TCM residues across 2020 and 2021, with 2020 representing a period before chlorine-free cleaning was introduced and 2021 being the period after chlorine removal. In 2020, 15% of the samples analysed had detectable levels of chlorate (0.0020–1.6 mg/kg), but this reduced to 8% in 2021 (0.0020–3.9 mg/kg), following the introduction of ‘chlorine-free’ cleaning. Chlorate and TCM residues have not been totally eliminated because sources of residue other than cleaning chemicals exist, i.e., chlorinated water.

From bowls to pots: The dairying revolution in Northwest Turkey, a view from Barcın Höyük, 6600 to 6000 BCE

Research has identified Northwest Turkey as a key region for the development of dairying in the seventh millennium BCE, yet little is known about how this practice began or evolved there. This research studies Barcın Höyük, a site located in Bursa’s Yenişehir Valley, which ranges chronologically from 6600 BCE, when the first evidence of settled life appears in the Marmara Region, to 6000 BCE, when Neolithic habitation at the site ceases. Using pottery sherds diagnostic by vessel category and type, this paper aims at identifying which ones may have been primarily used to store, process, or consume dairy products. Organic residue analysis of selected samples helped address the process of adoption and intensification of milk processing in this region over time. The lipid residue data discussed in this paper derive from 143 isotopic results subsampled from 173 organic residues obtained from 805 Neolithic potsherds and suggest that bowls and four-lugged pots may have been preferred containers for processing milk. The discovery of abundant milk residues even among the earliest ceramics indicates that the pioneer farmers arrived in the region already with the knowhow of dairying and milk processing. In fact, these skills and the reliance on secondary products may have given them one of the necessary tools to successfully venture into the unfarmed lands of Northwest Anatolia in the first place.

Livelihood Alternatives in Restored Peatland Areas in South Sumatra Province, Indonesia

Livelihood loss and lower income because of peatland mismanagement are crucial issues that must be resolved in peatland areas. Although many studies have assessed farmers’ livelihoods and income enhancement, progress in addressing these problems remains inadequate. To address this issue, this study aimed to analyze various existing alternative livelihoods in the peatland community in Ogan Komering Ilir District, South Sumatra Province, Indonesia, and analyze scenarios for creating livelihoods and increasing people’s incomes through changes in peat ecosystem management and peatland restoration programs. This study used a survey method conducted in South Sumatra Province’s OKI District, one of the four priority peat-restoration districts in the province. We used three sampling stages, while descriptive, tabulated, and mathematical methods were used for analysis. We analyzed the feasibility of livelihoods that used benefit-cost analysis. The results showed that Sonor cultivation of paddies and catching fish in Rawang (swamp) were the livelihoods of farmers in peatlands. The community has also been processing peatland commodities into other products, such as Purun woven, and Gula Puan (buffalo milk processing). Several alternative livelihood scenarios that are financially profitable and can be developed include salted and smoked fish, Purun woven handicrafts, paludiculture, and agrosilvofishery, which can provide farmers with short-, medium-, and long-term income opportunities. This study can contribute to policymaking by fully considering the role of peat resources in rural livelihoods.

Heat Treatment and Homogenization Influence the Gastric Digestion of Bovine Milk Protein in Growing Pigs as an Adult Human Model

BackgroundBovine milk processing influences the structure of the curd formed during gastric digestion, which may alter gastric protein hydrolysis and impact amino acid (AA) release into the small intestine. ObjectivesThis study aimed to determine the influence of heat treatment and homogenization on the gastric protein digestion and AA emptying of bovine milk. MethodsNine-wk-old pigs (n = 144) consumed either raw, pasteurized nonhomogenized (PNH), pasteurized homogenized (PH), or ultra-high-temperature homogenized (UHT) bovine milk for 10 d. On day 11, fasted pigs received the milk treatment (500 mL) before gastric contents were collected at 0, 20, 60, 120, 180, and 300 min postprandially. The apparent degree of gastric protein hydrolysis (based on the release of free amino groups), apparent gastric disappearance of individual proteins [based on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) gel band intensity], and the gastric emptying of digested protein and AA were determined. ResultsDuring the first 60 min, the rate of apparent gastric protein hydrolysis was fastest in pigs fed UHT milk (0.29%/min compared with on average 0.07%/min in pigs fed raw, PNH, and PH milk). Differences in the apparent degree of gastric protein hydrolysis and emptying were reflected in the rate of digested protein entering the small intestine. The AA gastric emptying half-time was generally shorter in pigs fed PH and UHT milk than in pigs fed raw and PNH milk. For example, the gastric release of total essential AA was >2-fold faster (P < 0.01) in pigs fed PH or UHT milk than that in pigs fed raw or PNH milk (i.e., homogenized compared with nonhomogenized milk). ConclusionsHeat treatment and homogenization increased the apparent gastric degree of protein hydrolysis and the release of digested protein into the small intestine. However, the rate of AA entering the small intestine was mainly increased by homogenization.

Assessment of halal blockchain in the Indonesian food industry

PurposeThe demand for halal food products is increasing globally. However, fraudulent activities in halal products and certification are also rising. One strategy to ensure halal integrity in the food supply chain is applying halal blockchain technology. However, to date, a few studies have assessed the factors and variables that facilitate or hinder the adoption of this technology. Thus, this study aims to assess the significant factors and variables affecting the adoption of halal blockchain technology.Design/methodology/approachA Delphi-based approach, using semi-structured interviews, was conducted with three food companies (chicken slaughterhouses, milk processing plants and frozen food companies). The cognitive best–worst method determines the significant factors and variables to prioritise halal blockchain adoption decisions.FindingsThe results showed that the most significant factors were coercive pressure and halal strategy. Nineteen variables were identified to establish a valid hierarchical structure for halal blockchain adoption in the Indonesian food industry. The five significant variables assessed through the best–worst method were demand, regulator, supply side, sustainability of the company’s existence and main customers.Practical implicationsThe proposed halal blockchain decision structure can assist food companies in deciding whether to adopt the technology.Originality/valueThis study proposes 19 variables that establish a valid hierarchical structure of halal blockchain adoption for the Indonesian food industry.

EFFECT OF DAIRY AND MEAT WASTEWATER IRRIGATION ON SEEDLING GROWTH

Milk and meat processing industries release large quantities of nutrient-rich wastewater with organic compounds (proteins, fats, carbohydrates) in high concentrations. Reusing and recycling this biodegradable wastewater for crop irrigation could be a sustainable solution once the phytotoxic effects of wastewater on crops have been investigated. Therefore, the aim of this study was to evaluate the effects of milk and meat processing wastewaters on germination percentage, seed vigour indices, the seedling tolerance index and the phytotoxicity index of pea (Pisum sativum L.), sugar maize (Zea mays saccharata), purslane (Portulaca oleracea), wheat (Triticum aestivum) and red spinach (Amaranthus dubius). The two wastewater types were collected at the inlet of the city’s sewage system and analysed to determine their physicochemical and microbiological characteristics. The seeds of all five plant species were irrigated with untreated wastewater effluents. The highest - germination percentages were obtained for wheat (92%) and the lowest for red spinach (2.5%). Wheat, purslane, pea and red spinach samples irrigated with meat processing wastewater had higher germination percentages than samples irrigated with dairy wastewater. A higher phytotoxicity was observed for sugar maize, followed by red spinach irrigated with both types of wastewater. Future investigation into the effects of effluent dilution on these types of plants is recommended.

The Effect of High-Pressure Processing of Caprine Milk on the Production and Properties of Yoghurt.

The aim of this study was to determine the suitability of HP-treated caprine milk for yoghurt production and to evaluate the effect of HP treatment on yoghurt properties. Reconstituted caprine milk was subjected to HP treatment (350 MPa/10 min/20 °C); a lactic acid starter culture (YC-X16, Chr. Hansen) was added. Milk was fermented at a temperature of 43 °C until pH 4.60. Bacterial counts, pH, color, rheological characteristics, texture, microstructure, and the sensory attributes of the yoghurt were determined after production and after seven days of storage at a temperature of 4 °C. HP treatment increased color saturation and whiteness index and induced a minor increase in milk pH. Minor differences in the acidification curve were noted. During storage, Streptococcus thermophilus counts were significantly higher in yoghurt from HP-treated than from untreated milk, whereas Lactobacillus delbruecki ssp. bulgaricus counts remained stable. A color analysis did not reveal differences between the experimental and control yoghurts. After storage, yoghurt made from HP-treated milk was characterized by thicker consistency and lower rheological stability than the control yoghurt. The micrographs of the yoghurts confirmed the differences in rheological parameters. Yoghurt produced from HP-treated caprine milk and stored for seven days received the highest scores in the sensory evaluation.

Investigating Milk Fat Globule Structure, Size, and Functionality after Thermal Processing and Homogenization of Human Milk.

Human milk provides bioactive compounds such as milk fat globules (MFGs), which promote brain development, modulate the immune system, and hold antimicrobial properties. To ensure microbiological safety, donor milk banks apply heat treatments. This study compares the effects of heat treatments and homogenization on MFG's physicochemical properties, bioactivity, and bioavailability. Vat pasteurization (Vat-PT), retort (RTR), and ultra-high temperature (UHT) were performed with or without homogenization. UHT, RTR, and homogenization increased the colloidal dispersion of globules, as indicated by increased zeta potential. The RTR treatment completely inactivated xanthine oxidase activity (a marker of MFG bioactivity), whereas UHT reduced its activity by 93%. Interestingly, Vat-PT resulted in less damage, with 28% activity retention. Sialic acid, an important compound for brain health, was unaffected by processing. Importantly, homogenization increased the in vitro lipolysis of MFG, suggesting that this treatment could increase the digestibility of MFG. In terms of color, homogenization led to higher L* values, indicating increased whiteness due to finer dispersion of the fat and casein micelles (and thus greater light scattering), whereas UHT and RTR increased b* values associated with Maillard reactions. This study highlights the nuanced effects of processing conditions on MFG properties, emphasizing the retention of native characteristics in Vat-PT-treated human milk.

The Transmission of Campylobacter Strains in Dairy Herds in Different Housing Systems.

Cattle are frequent carriers of Campylobacter spp.; therefore, these bacteria may be transmitted to humans through meat or milk. Campylobacter spp. in raw milk derives most commonly from secondary fecal contamination during the milking process; however, the udder excretion of Campylobacter may be a cause of milk-borne infection. Studies were carried out on a Campylobacter-positive farm with two different housing systems (with free-stall and tie-stall systems). The sampling process comprised several stages, including samples being taken from animals, such as from raw milk and feces, and from the environment, such as the from floor in the milking parlor and from teat cups. None of the individual raw milk samples or swabs from the floor in the parlor before the milking process were positive for Campylobacter spp. Simultaneously, Campylobacter spp. was isolated from all swabs from the floor after the milking process and in the bulk tank milk samples from the two farms. The incidence of Campylobacter isolated from fecal and teat swab samples ranged from 15.4% to 26.7% and from 8.9% to 25%, respectively. Altogether, 59 recovered Campylobacter isolates were classified, based on sequencing of the flaA short variable region, showing 15 different allele types, and the majority of them were distributed among one farm. Analysis of the virulence and antimicrobial properties showed that genes related to adherence, invasion and cytotoxicity were widely distributed among the Campylobacter recovered strains. In relation to AMR, multidrug resistance was noted in 16.1% of strains.

Predictive modeling of milk adulteration with urea content using the gray wolf optimization algorithm and long and short-term memory network model

Traditional methods for the determining of urea contaminants in milk, including chromatography, spectrophotometry, and electrochemical processes, have drawbacks such as long testing times and sample destruction. However, hyperspectral imaging technology provides a fast, easy-to-operate, and real-time alternative. In this study, five preprocessing methods are employed, including standard scalar, standard normal variational, first derivative, multivariate scattering correction algorithm, and Savitzky-Golay smoothing. To further enhance the accuracy of predicting urea content in milk, a prediction optimization method based on the gray wolf optimization algorithm for the long short-term memory network was proposed, using a competitive adaptive reweighted sampling algorithm feature wavelength selection algorithm. In the optimized model in the test set experiments, the decision coefficient was improved by 0.56% to 0.9906, and root mean square error was reduced by 7.69% to 0.4996 compared to the long short-term memory network model. This study not only provides a theoretical basis but also presents a fast and nondestructive detection method for accurately predicting urea content in milk.

Consumer Behavioural Patterns Towards Milk and Dairy Products: An Analytical Investigation of an Indian Dairy Supply Chain

Background: India has the most significant milk production and consumption level in the world. Fluid milk consumption will rise to 90 million metric tons in FY 2024 (Annual Report 202-23, United States Department of Agriculture). Milk is an essential component of daily diet in every age segment in India. Consumers’ behaviour and consumption patterns are based on their choices and preferences about product quality, price and preferences. This article critically investigates the consumer perception towards indigenous dairy markets and their consumption and behavioural pattern. Methods: Quantitative approach and Multiple Logistic Linear Regression Analysis (MLLRA) technique was used to test the hypothesis to establish a direct and indirect relationship among endogenous and exogenous variables. The sample was drawn from rural and urban regions of India’s top ten milk-producing states. Result: The research findings suggested a significant relationship between the direct and indirect role of consumers buying behaviour characteristics towards milk and dairy products and their satisfaction level. This research is limited to milk processors, dairy companies and dairy scientists in the field of marketing and dairy research. Dairy Farmers, Processors and Producers are vigilant about the quality of food products, especially milk delivered to their end users and their value-addition in the Milk Supply Chain (MSC) and logistics. In the past three years, during the unprecedented COVID-19, consumers’ consciousness level about health and well-being has been argued.

Klasifikasi kualitas mutu susu pasteurisasi menggunakan metode klasifikasi k-Nearest Neighbor

Milk is a product that is often consumed because it has many good benefits for the body. One of the benefits of milk is that it contains calcium, which is useful for the growth of bones and teeth. However, many consumers still choose dairy products based only on their appearance, even though milk quality is not based on its appearance but is found during milk processing. Pasteurization is the process of heating whole milk at a specific temperature and for a certain period to increase the milk's shelf life and maintain the milk's quality. Two types of pasteurization processes are Long Temperature Long Time and High Temperature Short Time. k-Nearest Neighbor or k-NN is a data mining method used to classify objects from the data, using distance calculations or Euclidean Distance to look for similarities between neighbors. So, based on this problem, milk quality classification is carried out. The research was carried out by classifying milk quality using the K-NN method. The public data used to classify is 1,059 pasteurized milk data, with seven regular or ordinary attributes and one special or class attribute. The K values ​​that will be used in this research are k=3, k=5, and k=7. From the analysis of calculation results using the k-NN method, the accuracy values ​​obtained are k=3 is 97%, k=5 is 89%, and k=7 is 87%.

Incidence of Bacterial Contaminants in Fermented Milk (Nono/Kindirmo) Sold By Fulani Women to Consumers in Wukari Metropolis, Taraba State, Nigeria

A study was conducted to investigate contaminants in fermented milk sold by Fulani women in Wukari, Nigeria. Fifteen milk samples were obtained from five different sales points (A, B, C, D, and E) for analysis. The Standard Plate Count method was employed to detect contaminants, with spread plate techniques isolating bacteria. The total aerobic bacteria count on nutrient agar plates was found on sample 2 of sales point D with a bacteria count of 3.3 x 106. The total aerobic bacteria count on Manittol salt agar plates was found on sample 2 of sales point D with a bacteria count of 2.4×106. The highest bacterial growth was staphylococcus aureus with 73.33%. The least bacterial growths was Escherichia coli and Pseudomonas aeruginosa with 13.33% respectively. Sample 1 of sales point A, samples 1 and 2 of sales point D and sample 3 of sales point E show bacteria growth on the Mannitol salt agar plate, while the other samples shows no growth. Also on a Nutrient agar plate, sample 1, 2, and 3 of sales point A, sample 3 of sales B, sample 3 of sales point C, and sample 2 of sales point D were negative, while the other samples were positive. It can be concluded that the high incidence of contamination with bacteria in nono could be attributed to the unhygienic milking process and post-contamination after pasteurization and during sales.

Scientific and Technical Basis for the Development of an Induction Heating Unit for Milk Pasteurization

Introduction. Induction heating is a preferred heating technique for industrial, medical and consumer systems, because it has a number of advantages over traditional heat transfer methods. The advantages include energy efficiency, heating rate, safety of operation, cleanliness of the process, low metal consumption, simple design, and precise control of the temperature of the heated raw materials. An induction heating unit is especially important for farms involved in processing of milk and producing milk-based products. Aim of the Study. The study is aimed at developing a prototype unit for long-term pasteurization of milk using a container heated by induction currents and at selecting optimal operating conditions for the developed prototype unit. Materials and Methods.There was used 3D modeling in the KOMPAS-3D computeraided design system to develop the main components of a milk pasteurization prototype unit with induction heating. The container for raw materials, stirrer and lid are made of stainless steel AISI 304 and AISI 430. The inductor is a frame made of polymer material with a litz wire arranged in a spiral manner. The body of the prototype unit is made of aluminum composite material. The developing and debugging of the electronic circuit of the prototype unit power part was carried out with the use of the design program Proteus 7.10. The microcontroller Mega 2560 was used to make the power part of the electromagnetic induction generation unit. The controlled temperature was monitored by using the waterproof temperature sensor DS18B20. A thermal imager was used to visualize the propagation of the thermal field over the surface of the container walls. Results. The structure diagram of the developed prototype unit with induction heating for long-term pasteurization of milk is presented. The article gives grounds to the use of the necessary elements and actuators in the unit for pasteurization of milk in a container heated by induction currents. There are presented a diagram of the developed power part for the prototype unit and the results of testing it when heating containers made of various materials. An algorithm has been developed to control the operation and PID regulation of the milk pasteurization in an experimental unit with the use the Raspberry Pi microcomputer. The graphs of transient processes when changing the coefficients of PID temperature control are presented. Discussion and Conclusion. When testing the induction heating principle on stainless steels of different compositions, it has been concluded that for the efficiency of heating the container, there is required a ferromagnetic steel pad welded on top of the main container made of food-grade stainless steel. The developed system of inductors made it possible to create a prototype unit with two heating zones depending on the volume of processed raw materials that is important for small farms engaged in processing milk and producing milk-based products.

Destabilization of ultra-instantaneous ultra-high-temperature sterilized milk stored at different temperatures

Ultra-instantaneous UHT (UI-UHT, > 155°C, < 0.1 s) treated milk exhibits higher retention of active protein than regular UHT milk. However, UI-UHT products demonstrate increased susceptibility to destabilization during storage. This study aimed at monitoring the destabilizing process of UI-UHT milk across different storage temperatures and uncovering its potential mechanisms. Compared with regular UHT treatment, ultra-instantaneous treatment markedly accelerated the milk's destabilization process. Aged gel formation occurred after 45 d of storage at 25°C, while creaming and sedimentation were observed after 15 d at 37°C. To elucidate the instability mechanism, measurements of plasmin activity, protein hydrolysis levels, and proteomics of the aged gel were conducted. In UI-UHT milk, plasmin activity, and protein hydrolysis levels significantly increased during storage. Excessive protein hydrolysis at 37°C resulted in sedimentation, while moderate hydrolysis and an increase in protein particle size at 25°C resulted in aged gel formation. Proteomics analysis results indicated that the aged gel from UI-UHT milk contained intact caseins, major whey proteins, and their derived peptides. Furthermore, specific whey proteins including albumin, lactotransferrin, enterotoxin-binding glycoprotein PP20K, and MFGM proteins were identified in the gel. Additionally, MFGM proteins in UI-UHT milk experienced considerable hydrolysis during storage, contributing to fat instability. This study lays a theoretical foundation for optimizing UI-UHT milk storage conditions to enhance the quality of liquid milk products.

Prevalence and antimicrobial resistance profiles of mastitis causing bacteria isolated from dairy goats in Mukurweini Sub-County, Nyeri County, Kenya.

Ruminant mastitis continues to be a cause of economic losses in the dairy industry and remains a major public health hazard globally. This cross-sectional study was carried out in Mukurweini Sub-County of Nyeri County, Kenya, to investigate the prevalence of bacteria causing mastitis, risk factors associated with goat mastitis and the antibiotic resistance profiles of bacteria isolated from the goat milk. Farm level data on risk factors for mastitis was obtained from 56 farmers using a semi structured questionnaire. A total of 189 goat milk samples were collected. The goat's udder was observed for signs of clinical mastitis and the California Mastitis Test (CMT) used to test the milk for sub-clinical mastitis. All samples were then cultured for morphological identification of bacteria and strain typing by Matrix Assisted Laser Desorption/Ionization (MALDI)-Time of Flight (ToF) technique. Antimicrobial susceptibility of the isolated Staphylococcus aureus, coagulase-negative Staphylococcus (CoNS), Escherichia coli, Klebsiella oxytoca, Pseudomonas spp., Enterobacter spp., Proteus vulgaris and Escherichia vulneris to eight commonly used antibiotics was done by the disc diffusion method and validated by determining the presence of antibiotic resistance genes (mecA and blaTEM) using polymerase chain reaction method. The prevalence of clinical mastitis was 1.1% (2/189) while that of sub-clinical mastitis was 84.7% (160/189). Higher (p<0.05) prevalence of mastitis was observed in goats whose houses were cleaned fortnightly and in cases where farmers used same towel to dry different does' udders during the milking process. Thirteen different bacterial species were isolated from the milk samples and identified by MALDI-ToF, and these included S. aureus (22.0%), CoNS (20.3%), E. coli (18.1%), Pseudomonas spp. (14.3%), Enterobacter spp. (10.4%), K. oxytoca (6.0%), E. vulneris (1.7%), P. vulgaris (1.7%), Raoutella ornithinolytica (1.7%), Stenotrophomonas maltophilia (1.1%), Pantoea agglomerans (1.1%), Serratia marcescens (1.1%) and Cedeceas spp. (0.6%). One hundred pathogenic bacterial isolates were randomly selected and tested for antibiotic sensitivity to eight antibiotics out of which S. aureus were 97.5% resistant to Oxacillin and 100% sensitive to Ciprofloxacin. The CoNSs were 100% resistant to Oxacillin and 100% sensitive to Ciprofloxacin. E. coli were 93.9% resistant to Oxacillin, 69.7% sensitive to Ciprofloxacin and 87.9% sensitive to both Amoxicillin/Clavulanic acid and Meropenem. The antimicrobial resistant genes detected in S. aureus and E. coli were mecA [66.7%, 0%], and blaTEM [20% and 78.3%], respectively. In conclusion, the study showed that most of the does were affected by subclinical mastitis with the main causative bacteria being Staphylococci spp. and coliforms. Farmers need to be trained on improved control of mastitis by adoption of good milking practices and use of CMT kit for early detection of mastitis. Occurrence of multidrug resistance by key mastitis causing pathogens was shown to be prevalent and therefore there is need for development of intervention strategies.

The effect of antibiotics contained in milk on the quality and safety of dairy products

During storage, the organic substances of milk undergo a number of complex changes in composition and properties, and new chemical compounds are also formed that radically change the nutritional value, normal appearance, taste and smell of the product under the influence of a number of factors. factors. Regulation of biochemical and microbiological processes during storage and processing of milk is a current trend in the dairy industry. The purpose of the experiment is to determine the effect of antibiotics on the chemical composition, microbiological parameters and organoleptic properties of raw milk and fermented milk products. During the research, it was found that with increasing concentration of penicillin, the consistency of yogurt becomes liquid and heterogeneous, with an off taste and odor. The number of lactic acid bacteria was 3.1 × 104 CFU/ml with the maximum amount of antibiotics in the product (0.1 mg/kg) and 3.4 × 108 CFU/ml without it. Statistically significant differences in the organoleptic properties of yogurt were obtained at the highest concentration of chloramphenicol (0.1 mg/kg). In the remaining samples studied, antibiotic concentrations did not affect the consistency, taste and smell of the product.

Concurrent removal of carbon and nutrients in a one-stage dual internal circulation airlift A2O bioreactor from milk processing industrial wastewater: Process optimization, sludge characteristics and operating cost evaluation

In this work, a one-stage dual internal circulation airlift anaerobic/anoxic/aerobic (DCAL-A2O) bioreactor was continuously operated for concurrent removal of nutrients and organics from milk processing wastewater (MPW). Special configuration of the airlift A2O bioreactor created possibility of the formation of desired anaerobic, anoxic and aerobic zones in a single unit. The process functionality of the bioreactor was examined under three influential operating variables i.e. hydraulic retention time (HRT; 7–15 h), air flow rate (AFR; 1–3 L/min) and aerobic volume ratio (AVR; 0.324–0.464). The optimum region was identified at HRT of 13h, AFR of 2L/min and AVR of 0.437, leading to TCOD, TN and TP removal efficiency of 94.5 %, 59.6 %, and 62.2 %, respectively, and effluent turbidity of 8 NTU. The impact of feed biodegradability on the process performance of the bioreactor treating the MPW, soft drink wastewater (SDW) and soybean oil plant wastewater (SOW) was also assessed. From the results, the feed characteristics affected significantly the nutrients removal. Moreover, the feeding location played an effective role in the nutrient removal while treating the MPW at optimum operating conditions. In this study, the change in residual organic matters as soluble microbial products (SMP) was monitored at various operating conditions. In addition, the impact of SMP extracted from sludge, extracellular polymeric substances (EPS) comprising of loosely bound EPS (LB-EPS) and tightly bound EPS (TB-EPS) was analyzed on sludge characteristics as bio-flocculation and settleability properties. According to the obtained data, the increase in operating variables led to the reduction in contents of effluent SMP, sludge SMP, LB-EPS, turbidity, and SVI, thereby, the enhancement in the sludge characteristics. Meanwhile, analysis of microbial communities verified the presence of various functional bacterial species. The cost operating evaluation confirmed the cost effectiveness of the airlift A2O bioreactor in reduction of energy consumption for the MPW treatment.

Physicochemical and sanitary parameters of bovine bulk milk processing centers in the Amazon region, Peru

Evaluating quality and microbiological parameters in bovine milk processing centers is essential for ensuring public health and product quality and positively impacting the local economy. This study aimed to evaluate the physicochemical and sanitary parameters of bovine milk in the Amazon region. For this purpose, 31 samples were collected from milk processing centers in the region. The following quality parameters were evaluated: somatic cell count; physicochemical parameters: fat, protein, nonfat solids, lactose, ash, pH, and density; and microbiological parameters: mesophilic aerobic bacteria and total coliforms in the raw milk. For data analysis, mean comparison tests were performed using Kruskal‒Wallis and Tukey tests, and cluster and principal component analysis was performed using R software version 4.3.2 and InfoStat version 2018p. The results for the 31 milk processing centers showed significant differences in all the parameters evaluated; fat, somatic cell count, and density were within the technical specifications of the Supreme Decree N° 007-2017-MINAGRI. Microbiological analyses revealed significant variability in total coliforms and mesophilic aerobic bacteria. Cluster analysis revealed five groups with similar characteristics, with Group 1 exhibiting high somatic cell, lactose, and ash contents and Group 3 exhibiting higher fat contents. Principal component analysis highlighted the significant contributions of total coliforms, aerobic bacteria, and somatic cells to the degradation of milk quality. Although somatic cell counts meet specific standards, elevated levels of coliforms and aerobic bacteria are of concern. These findings are essential for ensuring food safety and improving milk quality.