Microbial Quality Of Raw Milk Research Articles

Impact of Raw Milk Quality on Dairy Products & Payment Systems

The trend of microbial quality of raw milk is affected by the seasonal variation in in milk production practices and ambient temperature with the season. A payment system, which includes testing for selected parameters, with subsequent rejection and/or penalties or bonuses, is considered functional to improving raw milk quality. In addition to the minimal legal requirements, milk may be graded (and paid) according to its “quality,” usually measured according to composition (fat, protein, lactose, other solids, free fatty acids), hygienic quality. Psychrotrophic microbes, particularly Pseudomonas spp., are found in the microbiota of chilled milk because they can grow at temperatures below their optimal growth temperature. Psychrotrophic counts ranging from 105 to 108 CFU/ml in refrigerated raw milk affect cheese quality, since the synthesized thermoresistant enzymes affect the nutritional value, sensory properties and texture. Therefore, stringent measures must be implemented throughout the dairy supply chain to ensure the microbial quality of raw milk is maintained at safe levels, thus safeguarding the integrity and safety of dairy products for consumers.

Effect of flower extract of Roselle (Hibiscus sabdariffa L) on microbial quality of raw milk of Etawa goats

Effect of flower extract of Roselle (Hibiscus sabdariffa L) on microbial quality of raw milk of Etawa goats

The Impact of Raw Milk Quality, particularly Thermoduric, and Storage Temperatures on the Keeping Quality of Pasteurized Milk

Abstract This study was aimed to investigate the effect of raw milk qualities on their corresponding pasteurized milk stored at different chilled temperatures. Raw milk collected from two different sources, Banhong (BH) milk farm and Mae Tha (MT) collection center, were pasteurized at 78 ± 2ºC for 30 s and kept for 21 days at 4-8ºC. During the storage period, representatives of milk treatments were assessed for their chemical, microbiological and sensorial characteristics. Collected data revealed that there was only minor alteration for the chemical properties of pasteurized milk throughout the studied storage period. The microorganism numbers in the pasteurized milk were significantly increased during storage and higher at higher storage temperatures. Poorer microbial quality of raw milk, including thermoduric bacteria, strongly contributed to higher microbial load of the correspondence pasteurized milk during chilled storage. The coliform number of all the pasteurized milk samples was found to be below 1 cfu/ml during 21 days of storage, while no Escherichia coli, Listeria monocytogenes and Staphylococcus aureus was detected in the pasteurized milk samples. The appraisal of the sensory features of pasteurized milk, including color, flavor, odor, creamy taste, texture and overall acceptance, were gradually decreased with longer storage period. Keywords: Pasteurized milk, Storage temperatures, Raw milk, Microbial quality, Chemical properties

Bacterial Milk Quality along the Value Chain in Smallholder Dairy Production.

This study aimed to evaluate the microbial quality of raw milk along the milk value chain at Africa University (AU). Eighteen Holstein-Friesian cows were used in this experiment. A total of 270 milk samples were collected for laboratory analysis at three different stages, during milking (DM), from the bulk tank (BT), and at the dining hall (DH), to determine the total bacterial count (TBC), Escherichia coli, and Salmonella enterica. Samples were cultured in Petri dishes using an appropriate medium for 48 hours. The plate count method was used to determine the quantity of bacteria. Data were analyzed using GLM SPSS. The results indicated that TBC increased (P < 0.05) from one site to the next along the value chain, yet it undulates when measured over time. Escherichia. coli and S. enterica counts increased (P < 0.05) at the last site of collection and the highest counts were recorded in week two. In conclusion, the current study indicates the hygiene of the dairy parlor with very low TBC, E. coli, and S. enterica counts during milking and bulk tank storage and that the relationship between TBC and E. coli is nonlinear with respect to time.

Assessment of hygiene practices and microbial safety of milk supplied by smallholder farmers to processors in selected counties in Kenya

Smallholder farmers dominate the Kenyan dairy sector producing 95% of the total milk. However, several concerns have been raised on the quality and safety of the milk they produce. This study assessed the hygienic practices and microbial safety of milk supplied by smallholder farmers to processors in Bomet, Nyeri, and Nakuru counties in Kenya. Interviews and direct observations were carried out to assess hygiene and handling practices by farmers and a total of 92 milk samples were collected along four collection channels: direct suppliers, traders, cooperatives with coolers, and cooperatives without coolers. Microbial analysis was done following standard procedures and data analysed using GenStat and SPSS. This study revealed that farmers did not employ good hygienic practices in their routine dairy management. They used plastic containers for milking and milk storage (34.2%); they did not clean sheds (47.9%) and did not set aside cows that suffered from mastitis factors (83.6%), resulting in poor microbial quality of raw milk along the collection channels. The highest mean total viable counts (8.72 log10 cfu/ml) were recorded in Nakuru while Nyeri had the highest mean E. coli counts (4.97 log10 cfu/ml) and Bomet recorded the highest mean counts of 5.13 and 5.78 log10 cfu/ml for Staphylococcus aureus and Listeria monocytogenes respectively. Based on all above-mentioned parameters, the microbial load in most samples from all three counties exceeded the set Kenyan standards. Farmer training, improving road infrastructure, use of instant coolers at cooperatives, and quality-based payment systems are recommended as measures to curb microbial growth.

Microbial quality of raw cow milk and its predictors along the dairy value chain in Southwest Ethiopia

Raw milk may contain pathogenic microorganism that can seriously affect the health of consumers. In Southwest Ethiopia, raw cow milk is consumed more than the processed products, but its microbiological quality and its predictors are not studied well. The aim of this study was to determine the microbial quality of raw cow milk and its predictors along the dairy value chain in Southwest Ethiopia. A total of 150 milk and 300 environmental samples were collected randomly from dairy farms, milk distribution centers, and retailer outlets for microbiological analysis using standard protocols. One milk handler from each milk production or distribution stage was also interviewed to assess the knowledge, attitude, and practices regarding milk handling. Descriptive statistics and multiple linear regression models were used to summarize the data and to identify predictors of milk microbial quality, respectively. As the milk transported from dairy farm to milk retailer outlet, the mean total bacterial count has increased from 5.0 ± 0.3 to 7.2 ± 0.1 log CFU/ml respectively. The mean coliform count of the milk sample was 4.4 ± 0.4 log CFU/ml at the dairy farm and 7.0 ± 0.2 log CFU/ml at milk selling points, indicating the deterioration of milk quality along the dairy value chain. All of the analyzed water samples were positive for fecal coliform bacteria. The highest coliform bacteria were reported from milk storage equipment found at milk retailer outlet with the count of 4.8 ± 0.5 log CFU/ml. Educational status and attitude of milk handlers and the quality of water used to wash milk equipment and hands of milk handlers were the major factors affecting the microbial quality of raw cow milk. The findings of this study revealed that the microbial quality of raw milk in the study area was poor. Hence, improving the attitude and educational status of milk handlers, and the quality of water is an important step to enhance milk quality and consequently to prevent milk borne diseases.

Clean milk production practices and its impact on the prevention and control of mastitis in Tiruchirapalli district of Tamil Nadu

Mastitis is one of the major infectious diseases affecting dairy cows and causing economic loss. Majority of the rural dairy farmers are not aware of preventing mastitis through management practices. Lack of adoption of clean milk production practices is the major reason for mastitis. So the focus of study was imparting knowledge on clean milk production practices to dairy farmers from selected villages in Tiruchirapalli district along with management of mastitis in dairy animals through capacity building programme. After the adoption of clean milk production practices, there was remarkable reduction in the incidence of mastitis from 19.33 per cent to 2.4 per cent. The keeping quality of milk was also improved by enhancement in methylene blue dye reduction time (MBRT). This was an indirect indication of improved microbial quality of raw milk. The subclinical mastitis was monitored with somatic cell count (SCC) and the quarters of udder health by California mastitis test (CMT) respectively. The mastitic animal was treated effectively with suitable antibiotic by conducting antibiotic sensitivity test (ABST) and thereby protected the dairy farmers from huge economic loss.

Study on Physico-Chemical and Microbial Quality of Raw Milk Collected From Different Places of Assi Region in Varanasi City, Varanasi

The present study was conducted to evaluate the physico-chemical characteristics including Adulteration and Microbiological quality of cow raw milk collected from four different places of ASSI region in Varanasi. Samples were analysed to know the chemical composition, the results showed that the statistically average percentage of Moisture (87.46), Fat (3.87), Protein (3.15), Lactose (4.42), Ash (.712), pH (6.43) and acidity (0.147). The keeping quality of milk was evaluated by Methylene Blue Reduction Test (MBRT). This phenomenon testified that milk sample 1 is fair quality and remained sample were found good and excellent. The microbiological conclusion confirmed the presence (less or more) of microbial load in all the raw milk samples. The highest level of microbial quality in standard plate count (SPC) was 19.1×106 cfu/ml. in sample 1 and in logarithm value is 7.28 cfu/ml at the same time, the highest coliform bacteria 2.3×102 in logarithm value is 2.36 was found in the sample 2. The adulterations in raw milk were checked by the standard procedure. In cow’s raw milk the different mixed adulterant were found in two samples contaminated with detergent and pulverized soap. Besides different hazardous chemical adulterant, raw milk from sample 1 was detected with presence of hydrogen peroxide and sample 2 was contaminated formalin whereas urea was present in sample 2 and 4. Milk adulteration is a global concern and social problem. Increased demand, growth in competition in dairy industry and financial gain makes some producers to adulterate the milk thereby decreasing milk quality.

Microbiological quality assessment of raw milk and water samples from Noakhali district, Bangladesh

This study was carried out to evaluate the microbial quality of raw milk and water samples taken at four different local shops in Maijdee area (Noakhali District), Bangladesh. Milk is a valuable food-stuff consumed on daily basis and is highly prone to bacterial contamination. Contamination with pathogenic microorganisms is most alarming for potable water and hence it is needed to detect the bacterial contamination in local drinking water. Microbiological quality of milk samples was analyzed using Total Viable Bacterial Count (TVBC), Total Coliform Count (TCC) and Yeast-mold Count techniques. Critical hygienic indicator for food and foodstuffs is total microbial load. Compare to four stores, store 3 shows the high contamination value in milk samples (TVC 12.48×105 cfu/ml, TCC 6.4×105 cfu/ml, yeast- mold count 3.48×102 cfu/ml and 4.85×102 cfu/ml) whereas store 1 is liable to water samples (TVC 12.09×105 cfu/ml, TCC 4.81×105 cfu/ml, yeast- mold count 2.7×102 cfu/ml and 2.24×102 cfu/ml). These outcomes accentuate applying and sustaining proper hygiene practice throughout the manufacturing and distribution to prevent health risks of the rural people.&#x0D; Asian J. Med. Biol. Res. March 2019, 5(1): 31-36

Aerobic Plate Count of Milk and Dairy Products Marketed in Different Zones of Chennai

The present study was envisaged to ascertain the aerobic plate count of milk and dairy products as it may imply presence of potential pathogenic organisms which is a major concern in consumer’s health point of view. A total of 567 samples, which comprises of 75 raw milk, 45 pasteurized milk and 447 dairy products were purchased from various retail outlets in different zones of Chennai. The results obtained were subjected to statistical analysis by using IDM®SPSS®Version 20.0 for windows®. Results of our study showed highest count from Chennai central zones. The microbial quality of raw milk and pasteurized milk samples tested from all the zones was found to be satisfactory. However, concentrated dairy products and khoa based dairy products tested were of unsatisfactory quality, and therefore, hygienic precautions should be taken by determining critical control points along with routine inspection of such dairy products during processing, storage, distribution and marketing.

Extended storage of cold raw milk on yogurt manufacturing

Abstract: The objective of this work was to evaluate the effect of the extended cold storage of raw milk on the kinetics of fermentation on yogurt production, as well as on the product’s microbiological and physicochemical properties during shelf life. Three treatments were evaluated: yogurts made with raw milk stored for 4, 72, and 168 hours. Kinetics of fermentation was assessed through the lactic acid production rate, growth rate of Streptococcus thermophilus and Lactobacillus bulgaricus, and time to reach pH 5.0 and 4.5. The physicochemical and microbiological characteristics of raw milk and yogurts were also analyzed during cold storage at 4°C. The microbial quality of raw milk was affected by the storage time of 168 hours, with a decreasing tendency in the mesophiles:psychrotrophs ratio. Extended storage of raw milk beyond 72 hours negatively affects yogurt production, despite the low initial bacterial count, decreasing lactic acid production, S. thermophilus growth rate, pH, and protein content. Therefore, to optimize fermentation and yogurt shelf life, the maximum storage time for raw milk at 4oC should not exceed 72 hours.

Evaluation of Microbiological Quality of Raw Milk from Farmers and Dairy Producers in Six Districts of Djibouti

Objectives: The present study was carried out to evaluate the microbial quality of raw milk taken at different sampling points from farmers in Ali Sabieh, Arta, Dikhil, Djibouti, Obock and Tadjourah districts of Djibouti. Methods: Two hundred samples of milk extracted from goats, cows and camels were collected and analyzed for the presence and enumeration of microorganisms using standard methods. Total bacterial counts exceeded the national standard in 56% of collected samples and Tadjourah district had higher milk samples (82%) with unacceptable total bacterial count. Results: Key data demonstrated the presence of food-borne microorganisms. The mean value of aerobic mesophilic bacteria (6.78 log cfu mL-1), coliform counts (3.91 cfu mL-1) and E. coli count (2.58 cfu mL-1) was higher than maximum recommended value. The count of yeast and moulds (5.54 log cfu mL-1) was also very high. Salmonella spp. (0.10 log cfu mL-1) was only detected in the samples from Ali Sabieh district whereas Staphylococcus aureus and spore of Clostridium spp. were below the detection level in all samples. Count of Brucella spp. and Mycobacteria were 0.56 log cfu mL-1 and 0.86 log cfu mL-1 respectively suggesting the existence of mastitic animals. Pearson correlation matrix of microorganism’s distribution in raw milk showed highest positive correlation between Yeast and moulds and Streptococci at r=0.929. Analysis in principal components exhibited the variability of microbial groups with 80.797% cumulative values of the variance and Eigen values ranging between 1.553 and 3.622. Conclusion: The data suggested that raw milk samples collected from the six districts were non suitable quality and most of bacteria identified in the milk sampled could be potential food-borne pathogens.

Survey of physicochemical characteristics and microbial contamination in selected food locally vended in Morogoro Municipality, Tanzania.

BackgroundRaw milk, raw fruit juice and raw fish are enriched with essential nutrients for human diet but are prone to microbial contamination along the value chain. This cross sectional study was conducted to assess physicochemical characteristics and microbial quality of raw milk, fruit juice and fish from food vendors in Morogoro Municipality, Tanzania. The physicochemical assessment of food samples was done by smell, colour, presence of debris, turbidity, consistence, pH and clot on alcohol test. Hygiene of food containers, personnel and the vending environment was also assessed. Qualitative and quantitative microbial assessment of food was done using standard laboratory protocols as described by Tanzania Bureau of Standards and International Systems of Standards.ResultsRaw milk sold in Morogoro was of poor quality since was adulterated with water, contained sediments and clotted on alcohol test. Up to 63 % of the milk samples were contaminated with Escherichia coli and 60 % had higher total viable count (TVC) than the recommended values. Raw fruit juice was stored in dirty containers and sold under unhygienic environment. Seventy-three percent of juice samples had TVC beyond the recommendations while E. coli contamination rate was 63.3 %. The raw fish samples had started spoiling as depicted through sensory evaluation. E. coli contamination rate was 55 % and that of Campylobacter jejuni was 0.5 %. The mean TVC of raw fish was 8.1 (Log cfu/g) and 96.2 % of the fish samples had TVC beyond the recommended limits of 5.0 Log cfu/g.ConclusionsThe physicochemical characteristics of food vended in Morogoro Municipality were of poor quality. The food had high bacterial contaminations. This situation poses health risks to the public and losses to food vendors due to spoilage. Stakeholders in food value chain should be educated on safe production and good hygienic practices. Routine quality and safety assessment of locally vended food, inspection of selling premises and regular health check-up of the personnel involved in food vending industry should be instituted.

Short communication: Microbial quality of raw milk following commercial long-distance hauling

Hauling is a critical part of the commercial milk supply chain, yet very few studies have aimed to understand its effect on raw milk quality. This study focused on the effect of extended-duration tanker use during hauling on raw milk quality at a commercial facility. Standard tanker use [cleaned-in-place (CIP) once per 24h] served as a control and an incremental between-load water rinse with sanitizer treatment (RS) was evaluated to mitigate any effect from extended duration hauling. During this study, 1 commercial truck with 2 trailers was monitored for 10d. The truck collected milk at a large dairy farm, transported the milk to a manufacturing facility, and then returned to the same farm for a second load. Each round-trip journey took between 10 and 12h, allowing for 2 loads per 24-h use period. Following the second delivery, the truck was cleaned by CIP treatment starting a new treatment day. Producer samples were collected from the raw milk bulk tank on the farm before loading milk into the tanker. The same milk was sampled directly out of the tanker truck before unloading at the manufacturer. Effect on individual bacteria count, thermophilic spore count, and preliminary incubation count was quantified through common industry tests. Surface sponge swabs were also used to monitor tanker sanitation and the efficacy of cleaning treatments. Results did not identify a negative effect on raw milk quality due to extended duration hauling. Whereas the addition of RS did not provide any measurable quality benefits for the microbial milk quality, swab results demonstrated that the RS treatment was able to reduce surface bacteria in the tanker, although not to the same level as the full CIP treatment. Based on this study, current CIP practices for long distance milk hauling appear to be effective in mitigating any measurable effect on raw milk quality.

Pathogenic and Drug Resistant Bacteria in Raw Milk of Jessore City: A Potential Food Safety Threat

Milk is such a food which can meet almost all nutritional needs of human lives. Raw or unprocessed milk supports the growth of wide variety of microorganisms. The major interests of this study were examining the microbial quality of raw milk collected from different locations of Jessore city in Bangladesh and determining antibiotic susceptibility pattern of some isolated bacteria. To do so, 12 raw milk samples were collected from different areas of Jessore city. Microbial analysis comprised of enumeration of TVC (total viable count), TCC (total coliform count) and TSC (total staphylococcal count). The highest TVC, TCC and TSC were 1.95x109 CFU/ml, 2.5x107 CFU/ml and 1.02x107 CFU/ml respectively. Prevalent bacterial populations were Klebsiella spp., Enterobacter spp., Shigella spp. Staphylococcus spp., Escherichia coli and Citrobacter spp. In order to observe the antibiotic susceptibility pattern, the antibiotic sensitivity test was performed for some randomly selected isolates of E. coli and Klebsiella spp. More than 90% isolates of Klebsiella spp. were found to be resistant against Erythromycin whereas more than 90% isolates were sensitive against Imipenem. On the other hand, 100% E. coli isolates were observed as resistant against Erythromycin and in case of Trimethopreme 100% isolates were sensitive. Multidrug resistance pattern was also found. These results suggest the necessity of hygienic practices during handling, processing and post-processing of raw milk to improve the microbiological quality and safety of raw milk.DOI: http://dx.doi.org/10.3329/bjvm.v13i1.23723Bangl. J. Vet. Med. (2015). 13 (1): 71-78

High frequency of the potential pathogen Lactococcus garvieae in raw milk from Kosovo

The present study was undertaken to investigate the microbial quality of raw milk from dairy farms in Kosovo with emphasis on the potential pathogen Lactococcus garvieae. Based on selective media and growth profiles approximately 770 isolates were obtained from raw milk collected from 221 farms and 119 of these isolates were shown to belong to L. garviae based on 16S rRNA gene sequencing. The 119 L. garvieae isolates were derived from 43 farms. It also appeared that L. garviae was established as a persistent bacterium in these farms since it was found in most samples collected over a period of 6 months. The L. garvieae-containing farms were not geographically related as isolates of this bacterium were found across the country. Genetic diversity assessed by rep-PCR fingerprinting revealed 8 major groups and the largest group contained isolates from 13 farms. Isolates within the individual groups 1, 2, 3, 4, and 5 showed strong genetic relatedness while the isolates from the remaining groups 6, 7 and 8, did not give a clear picture of relatedness. Twenty one isolates showed weak alpha haemolytic activity and antibiotic resistance was demonstrated in 39 of the 43 isolates. Diversity in the fermentation profiles was also observed among the 43 L. garvieae isolates that could be divided into 5 separate fermentation groups.

Microbial Quality of Cow Milk in Dawa Chefa District, Amhara Region, Ethiopia

Background: The microbial load of milk is a major factor in determining its quality, which is indicates the cleanliness of the milking utensils, condition of storage, manner of transport as well as the cleanliness of the udder of the individual animal. The aim of this study was to determine microbial quality of cow’s milk. Methodology: The study was conducted in Dawa Chefa District, Oromia Zone of the Amhara National regional state. A total of 50 samples of raw cow's milk were collected at morning from hotels (27 samples), cooperative (3 samples) and household producers (20 samples). The farmers (producers) that involve in the study were selected based on potential of milk production, market orientation and willingness of households. Samples of raw morning milk were taken from each sampling point twice in a month. During collection, approximately 250 ml raw milk sample were taken aseptically from the owner’s container then placed into sterile glass bottles. Result: The average total plate counts of milk sampled from farmers, dairy cooperatives and hotels were 6.88 log10, 7.10 log10 and 7.54 log10, respectively. The average coliform counts were 5.57 log10 at farm level, 5.63 log10 for dairy cooperative and 5.37 log10 for hotels. The average yeast and mould counts at farmer, dairy cooperative and hotel were 0.46 log10, 0.62 log10, and 0.74 log10 cfu/ml, respectively. The indirect tests and the actual bacterial count indicated that the microbial quality of milk produced by farmer and collected by dairy cooperatives in the study area was poor and this calls for scrupulous hygienic measure during production and handling of milk. Conclusion: The result showed that the microbial quality of raw milk obtained from local dairy farmer was very low. This was due to the unhygienic condition of milking; unclean milk handling equipment and the use of contaminated water. Therefore, Proper hygienic practice will become a useful parameter and model for other dairy farmers within the district to improve and upgrade their dairy production.

Determinants of raw milk quality under a smallholder production system in selected areas of Amhara and Oromia National Regional States, Ethiopia

The determinants of raw milk quality were studied in 384 households from six districts of Amhara and Oromia National Regional States, Ethiopia. The analysis revealed that there is a significant difference (P<0.01) in all physico-chemical milk quality parameters among the districts. The overall mean percentages of fat, solid non-fat (SNF) and protein obtained were 5.22, 8.44 and 3.12 in that order. Protein level had positive and negative significant (P<0.01) correlations with lactose and freezing point respectively. Mean total bacterial count (TBC/ml), total coli form count (TCC/ml) and somatic cell count (SCC) were 1.1x10 8 , 3.0x10 4 and 5.5x10 5 , respectively and there were significant differences between study sites. Milk handling and adulteration practices were the most likely causes for the observed difference in microbial quality of raw milk. Breed, parity number, feeding system, farming experience and distance from dairy technology dissemination centers had significant influence on fat and protein percentages. Practicing different dairy technology which is supported with a continuous training on how to manage the farm and integrated with a near proximity veterinary service; stronger milk quality control establishment and quality base payment should be practiced to discourage adulteration.

The Microbial Quality of Raw Milk from four locations in Abia State, Nigeria

The Microbial Quality of Raw Milk from four locations in Abia State, Nigeria

Effects of season and agro-ecological zone on the microbial quality of raw milk along the various levels of the value chain in Uganda

Dairy production in Uganda is pasture-based and traditional Ankole cattle make up 80% of the cattle herd, reared in both pastoral and agro-pastoral ecological zones. Regardless of the zone, milk quality is lowest in production basin during the dry season when ambient temperatures are highest and water is scarce. Poor hygiene and quality management contributed to the deterioration of raw milk quality during its storage and delivery to the final consumer, and concealed the seasonal effect when milk reached urban consumption areas. Poor milk quality is a challenge for the Ugandan Dairy Development Authorities who wish to make the milk value chain safe. This study provides baseline information for the implementation of an HACCP-based system to ensure the hygienic quality of milk from the farm to the market place.