Bacterial Contamination Of Milk Research Articles

Pathogenic Bacteria and Their Antibiotic Resistance Patterns in Milk, Yoghurt and Milk Contact Surfaces in Debre Berhan Town, Ethiopia.

Bacterial contamination of milk is a primary culprit for causing foodborne illnesses, presenting a significant health hazard for millions of individuals around the globe. The level and variety of microorganisms present in raw milk determine its degree of contamination and the potential health risks it poses. A cross-sectional survey was conducted from February to August. A questionnaire was used to collect data on socio-demographic characteristics and hygiene practices from milk distributors and traders. Raw milk, yoghurt, swabs from milk containers and drinking cups were collected and processed for bacterial isolation and identification, antibiotic susceptibility testing, MDR screening and confirmation, ESBL screening and confirmation. Finally, all data were pooled and analyzed using SPSS software version 25. A total of 120 samples of fresh milk, yogurt and cotton swabs from milk containers and cups were collected. A total of 80 bacterial isolates were isolated from 120 samples. Among the bacteria isolated, S. aureus 17 (21.3%), E. coli 17 (21.3%), S. epidermidis 14 (17.5%), Klebsiella spp. 9 (11.3%) and Salmonella spp. 7 (8.8%) were detected most often. High rate of contamination was observed in fresh milk 23 (28.8%) and yogurt 23 (28.8%). All isolates were resistant to at least one antibiotic tested. Comparatively, high rates of resistance were observed in all isolates to the most commonly prescribed antibiotics in Ethiopia. However, lower rates of resistance have been observed for recently introduced antibiotics in Ethiopia. Of the isolates, 20 (25.0%) were resistant to eight or more antibiotics. While 16 (20.0%), 12 (15.0%), 9 (11.3%) isolates were resistant to two, three and five antibiotics, respectively. Of the bacteria isolated, 52/80 (65.0%) were MDR, 25/49 (51.0%) were screened for ESBL production, and 20/49 (40.8%) isolates were confirmed as ESBL producer. This study showed a high rate ofbacterial isolates along with MDR and ESBL-producing strains in raw milk, yoghurt, milk container swabs and drinking cup swab samples, associated with poor hygiene and sanitation practices.

ОЦЕНКА ИНФЕКЦИОННЫХ РИСКОВ МОЛОКА, РЕАЛИЗУЕМОГО В НЕ ПРЕДУСМОТРЕННЫХ ДЛЯ ТОРГОВЛИ МЕСТАХ

Milk is a good source of protein, calcium, vitamins, magnesium, casein. Its advantages are the pleasant taste, dietary features and the ability to quench thirst. However, in hygienic terms, it is not without drawbacks. In particular, milk is a beneficial environment for the development of various microorganisms, including pathogens, as a result of which it can easily become a carrier of infectious diseases. Therefore, the task was set to investigate the risks associated with the transmission of a number of dangerous zoonotic infectious diseases, in particular brucellosis and tuberculosis. To this end, organoleptic and laboratory studies were carried out on 20 samples of unpasteurized milk purchased from private individuals in different administrative districts of the city of Yerevan. Through organoleptic method the color, smell, taste, texture of milk was determined. Under laboratory conditions, pH, purity, density, total acidity, bacterial contamination of milk and the presence of brucellosis antibodies and causative agents of tuberculosis were detected. Milk samples were also examined for starch and soda content (milk adulteration).

Molecular characterization and microbial resistance of different bacterial isolates in some dairy products

Bacterial contamination of milk and dairy products is a common problem. In the last two years, the foodborne diseases caused by the intake of milk and dairy products have been mostly disturbed with Salmonella entertica, Listeria monocytogenes Escherichia coli 0157:H7 and Campylobacter jejune. The study aims to isolate multidrug resistance (MDR) bacteria in dairy products and study of the molecular characterization of that isolates. MDR bacteria were found in 30 out of the 131 bacterial isolates. The incidence of MDR bacterial isolates revealed the abundance of Staphylococcus sp. with 43.3%, Bacillus sp 16.7%, Salmonella 13.3%, E. coli 10 %, Enterococcus 6.7 % Psedoumonas 3.3 %, Shegella 3.3 % and Proteous 3.3 %. Molecular studies of genes presence or absence for class A contain TEM, CTX and BSHV, class B contain VIM, IMP, KPC and NDM, class C contain FOX and class D contain OXA-10, OXA-24 and OXA-58 were tested. NDM, TEM, CITM and OXA -10 genes were the most abundant the selected bacterial isolates. The results of this study indicate that cheese made from unpasteurized milk can pose a significant risk to consumers. Product manufacturing processes should be subject to health control-to-control pathogens. The novelty in this work depend on screening of gene responsible of the resistance from the bacteria isolated from dairy product using the molecular technique.

Вимоги щодо створення умов для утримання тварин на молочних фермах

The purpose of the research is – to develop requirements for creating comfortable conditions for keeping farm animals, taking into account EU standards, during milk production on farms. Research methods. During the development of requirements for the creation of comfortable conditions for keeping farm animals, taking into account EU standards, in the process of milk production on farms used the following basic regulations: Council Directive 98/58/EU, Council Directive 91/629/EU, Council Directive 92/46/EU, Commission Directive 89/362/EC. Requirements in the field of milk production, adapted to EU standards, are systematized by the following components: keeping, feeding, watering animals, milking cows, milk cooling, manure removal, creating a microclimate, veterinary care. Research results. In practice, during milk production it is necessary to create free, comfortable conditions for keeping cattle. Convenient access of service personnel to the place of calving of cows should be provided. In the conditions of the maternity ward, the technological areas should be 8-10 m² per cow. Young cattle, including calves, should be provided with a clean and dry rest area, protected from drafts. According to EU regulations, calves up to eight weeks of age can be kept in individual cages or in group cages. According to EU Council Directive 97/2, calves older than 8 weeks of age are kept only in group cages. In accordance with the EU Directive 97/2 technological areas for keeping young cattle with a live weight of up to 150 kg - must be at least 1,5 m² / head., Live weight 150 - 220 kg – 1,7 m² / head., Live weight 220 kg and more – 1,8 m² / goal. Technological areas for keeping animals with a live weight of 200 to 500 kg - from 2,7 to 4,7 m² / goal. The feeding front for young cattle with a live weight of 200 to 500 kg is from 0,4 to 0,6 m / goal. The technological area in the section per cow must be at least 6 m² / head. Rational sizes of boxes for rest of cows: width 1,2 m, length (near a wall) - 2,6 m, length (in paired boxes) - 2,45 m, height of a protection of a box - 1,1 ± 0,05 m, an inclination boxing floor towards the manure passage 5 ± 1%, the height of the boxing floor above the level of the manure passage 0,2 – 0,25 m. The width of the rest area of cows must be at least 6 m. In accordance with EU Council Directive 98/58 must be provided free access of animals to feeders and feed. EU Commission Decision 97/182 states that priority should be given to the feeding of whole milk substitutes when feeding calves. A feeding front for cows must be provided – 0,7 ± 0,05 m. In accordance with EU Council Directive 98/58, free access of animals to drinking troughs and water must be ensured. According to European standards, the total bacterial contamination of milk should be - ≤ 300 thousand KUO / cm³, the number of somatic cells in milk - ≤ 400 thousand /cm³. Drainage of wastewater from milking parlors, household premises of the farm is carried out using a separate from the manure removal system - sewer system. The bactericidal phase of fresh milk is 4 hours, no later than this period you need to start processing milk into dairy products. The depth of the manure channel in the livestock building should be 8 - 20 cm, the sides of which are located at right angles to the surface of the channel. The minimum width of the manure passage for cows should be 2,7 m. An acceptable level of air temperature for cows during the year from minus 10 °C to + 25 °C at a relative humidity of up to 80 %. Periodically carry out preventive veterinary measures, weighing animals, trimming the hooves of limbs in cows 2-4 times a year, monthly examination of cows for mastitis using mastitis detectors. Conclusions. For the first time in Ukraine, requirements have been developed to create comfortable conditions for keeping farm animals, taking into account EU standards, during milk production on farms. Requirements adapted to EU standards in the field of milk production are systematized by the following components: keeping, feeding, watering dairy cattle, milking cows, cooling milk, manure removal, creating a microclimate, veterinary care.

Оцінка визначення показників якості молока сучасними засобами

The purpose of research – is to analyze modern methods and tools for determining milk quality indicators. Research methods. Comparative studies of methods and means for determining milk quality indicators. The «Milkotester» milk quality analyzer of the «Master Eco» model is intended for measurement of mass fraction of fat, protein, dry skimmed milk residue, added water, freezing point, milk temperature, milk density. Approbation of a modern device for assessing the quality of milk "Milkotester" model "Master Eco" is carried out during the determination of the above indicators of milk quality on a dairy farm in comparison with standardized methods for determining indicators that characterize the quality of milk. Repeated measurements - 10. Research results. Testing of the «Milkotester» milk quality analyzer of the «Master Eco» model was performed in comparison with standardized methods. It is established that the device operates with an error when measuring the mass fraction of fat in milk ± 0,03 %, which meets the requirements of regulatory documentation for the device ± 0,1 %, the mass fraction of protein - ± 0,04 % and ± 0,1 %, respectively, mass fraction of dry matter - ± 0,04 % and ± 0,1 %, density - ± 0,1 kg/m3 and ± 0,3 kg/m3, added water - ± 2,3 % and ± 3,0 %, freezing points ± 0,002 °C and ± 0,005 °C, milk temperatures – ± 0,1 ° C and ± 1,0 ° C, respectively. The duration of determining the quality of milk of one sample by the device is 1,5 minutes. Conclusions. According to research, it is established that there is a constant improvement of methods and tools for assessing the quality of milk. In recent years, foreign companies have developed electronic devices for assessing the quality of milk. Some electronic milk quality analyzers have been developed in Ukraine as well. One of the most modern devices for assessing the quality of European-level milk "Milkotester" Bulgarian production provides a technological process for measuring the mass fraction of fat, protein, dry matter, added water, freezing point, milk temperature, milk density. The error in measuring the indicators that characterize the quality of milk meets the requirements of regulatory documentation for the device. In the market of Ukraine the electronic device "Charm Peel Plate" of the American production which is intended for definition of bacterial contamination of milk is offered.

Housing and management characteristics of calf automated feeding systems in the Upper Midwest of the United States

Automated milk feeders are used by dairy producers to manage preweaned calves in group housing, but little is known about how these feeding systems are being used in the United States. To better understand how US dairy producers are operating these systems, this study investigated characteristics of barn design, environment, and management practices on 38 farms in the Upper Midwest of the United States via a questionnaire and on-farm measurements. Farms using automated feeders ranged in size from 7 to 300 calves on site. Natural ventilation was used on 50% of the farms, followed by barns with mechanical ventilation (39.5%), tunnel ventilation (7.9%), or outdoor facilities (sheltered plastic domes; 2.6%). Calves were kept in groups of 17.6 ± 9.8 animals (range: 5.9 to 60.5) with an average space allowance of 4.6 ± 2.0 m2/animal (range: 1.6 to 11.9). Calves on these farms received 3.7 ± 0.75 L (range: 2 to 6) of colostrum, but 22% of the tested calves had serum total protein values lower than 5.0 g/dL. Calves had an initial daily allowance of 5.4 ± 2.1 L (range: 3 to 15 L) of milk or milk replacer, rising to a peak amount of 8.3 ± 2.0 L (range: 5 to 15 L) over 18 ± 11.4 d (range: 0 to 44 d). Milk replacer was fed to calves on 68.4% of the farms compared with whole milk supplemented with nutrient balancer on 23.7% and whole milk alone on 7.9% of the farms. Calves were completely weaned at 56.8 ± 9.0 d of age (range: 40 to 85.5) and 52.1 ± 7.5 d (range: 40 to 79) since introduction into the group pen with the feeder. Notably, bacterial contamination of milk was common; the median coliform count was 10,430 cfu/mL (interquartile range: 233,111; range: 45 to 28,517,000) and standard plate count was 2,566,867 cfu/mL (interquartile range: 15,860,194; range 6,668 to 82,825,000) for samples collected from the feeder tube end (or feeder hose). Some areas of deficiency might be of concern as they might be influencing the success of using automated calf feeding systems. In particular, a better understanding of the dynamics of pathogen load is needed in both the group pen area and in the automated feeder unit itself, as these reservoirs represent significant risk to calf health and welfare.

БАКТЕРІАЛЬНЕ ЗАБРУДНЕННЯ МОЛОКА ЗА РІЗНИХ ТЕМПЕРАТУР І ТЕРМІНІВ ЗБЕРІГАННЯ

Research was conducted in the laboratory LILCO, Surgères, France. For the first experiment, 24 samples of cooled bulk tank goat milk were selected be transported within 2 – 3 hours at different temperatures. Then all samples were stored day at 4 °C. The indicators of bacterial contamination, fat, protein, freezing point, somatic cell count, urea were similar for different temperatures of transporting milk samples. Noted the big somatic cell count (> 2000 thousand / ml) at low bacterial contamination (19,6 × 103 CFU/mL) of goat milk. Samples of milk can be delivered to the laboratory for 2–3 hours at a temperature of 2, 10 or 20 °C if the milk immediately after milking cooled and stored in a tank at 4 °C.10 samples of cow's milk (non–cooled – 3 hours after milking, cooled – after a day) were also examined. Bacterial contamination of milk which has been cooled and being stored one day at 4 °C was in 4.6 times less (P < 0.01) than non–cooled milk, analyzed in 3 hours after milking. This proves that bacterial contamination of milk in Ukraine accordance with European requirements (up to 100 thousand. CFU/ml) is possible only when rapid cooling of milk after milking to 4 оС and storing it in the cooling tank.

PHYSICOCHEMICAL AND BACTERIAL PROPERTIES OF PASTEURIZED MILK SAMPLES COLLECTED FROM TABRIZ, NORTHWESTERN IRAN

Milk and dairy products are important components of a balanced diet. Milk does have distinct physicochemical, biological and microbial characteristics. The bacterial contamination of milk not only reduces the nutritional quality but its consumption threatens health of the society. In this study, 100 pasteurized milk samples were collected randomly from Tabriz City, northwestern and were analyzed for total plate count (TPC), coliform, E. coli and some physicochemical properties (pH, titratable acidity and density). 33.3% of samples had unacceptable microbial contamination in both warm and cold seasons. E. coli contamination was not detected in all milk samples, but 54% of pasteurized milk samples were contaminated with coliforms. The pH value (6.6-6.8) and titratable acidity (0.14-0.16%) were in acceptable range. The means value of samples’ density was 1028.79±1.04. Lower microbial contamination level in this area indicates that the dairy factories are concerned about appropriate sanitary practice and pasteurization process.

Comparative evaluation of technological factors affecting milk production and quality with various milking technologies

The technological factors and characteristics of milking technologies in a linear milking pipeline with tethered housing, on Europarallel equipment, and on a DeLaval VMS robot with loose housing affecting milk productivity and quality is analyzed. The technological chain of the main factors of milking technologies is investigated. The number of mechanical effects on milk, primary processing of milk on the farm (filtering, cooling), sanitation of milk transport, and level of hygiene on the farm and in the milking parlor are analyzed. A comparative evaluation of the quality of milk taken from tanks with various milking technologies is carried out. The lowest somatic cell count and bacterial contamination of milk are noted with robotic milking (on average, respectively 195600 cm3 and 6200 CFU/cm3). The change in milk productivity of cows across lactations with different milking technologies is investigated.

Электропастеризатор молока

There were designed, manufactured and tested in a production a setting for disinfection of milk by exposure of physical factors, which has a new design concept of the working part in the form of a cylindrical cavity resonator, coupled to a reservoir of the ultrasonic generator, located in the shielding enclosure. The technological scheme of milk pasteurization in the developed electric pasteurizer comprises the steps of: supplying milk into the cavity, dielectric heating milk in a cylindrical cavity; the heating of milk due to the impact of the regional flow of electromagnetic field of microwave at its end from the cavity to the reservoir of the ultrasonic generator; cavitational heating milk in the tank of the ultrasonic generator; repeatedly pumping milk with a pump on the milk line; the bactericidal effect of ultraviolet rays on the flow of milk through the milk line; drain the milk in aseptic packaging. The study the dynamics of heating milk by combined effect of physical factors such as ultrasonic vibration and electromagnetic field of microwave, showed that the increase in temperature was over 200 ... 240ºC with 47 ... 48ºC. The study of microbiological parameters of bacterial contamination of milk with 5,1 * 106 KFU/cm3 showed that during the disinfection of milk by combined action of physical factors the total bacterial count (TBC) decreased to 100,000 KFU/cm3.

Relationship of Somatic Cell Count and Mastitis: An Overview

Mastitis is characterized by physical, chemical and bacteriological changes in the milk and pathological changes in the glandular tissue of the udder and affects the quality and quantity of milk. The bacterial contamination of milk from the affected cows render it unfit for human consumption and provides a mechanism of spread of diseases like tuberculosis, sore-throat, Q-fever, brucellosis, leptospirosis etc. and has zoonotic importance. Somatic cell count (SCC) is a useful predictor of intramammary infection (IMI) that includes leucocytes (75%) i.e. neutrophils, macrophages, lymphocytes, erythrocytes and epithelial cells (25%). Leucocytes increase in response to bacterial infection, tissue injury and stress. Somatic cells are protective for the animal body and fight infectious organisms. An elevated SCC in milk has a negative influence on the quality of raw milk. Subclinical mastitis is always related to low milk production, changes to milk consistency (density), reduced possibility of adequate milk processing, low protein and high risk for milk hygiene since it may even contain pathogenic organisms. This review collects and collates relevant publications on the subject. (

Incidence of psychrotrophic lipolytic bacteria in cow's raw milk

The contamination of bulk samples of cow’s raw milk (<I>n</I> = 491) by psychrotrophic lipolytic bacteria (PLiBC), total count of psychrotrophic bacteria (PBC) and mesophilic bacteria (TBC) was monitored for two years on eight dairy farms and the correlations among these groups of bacteria were analysed. An increase in TBC, PBC and PLiBC and in the values of free fatty acids (FFA) was tested experimentally in three milk samples in relation to time (analyses were done in 24-hour intervals until 96 hours) and storage temperature of milk samples (4; 6.5 and 10°C). Bacterial contamination of milk was determined by culture methods in accordance with IDF standards, the values of FFA were determined by an extraction-titration method. These mean values were determined in the set of samples (<I>n</I> = 491): PLiBC 659 CFU/ml, PBC 2 932 CFU/ml and TBC 18 932 CFU/ml. A high correlation was proved between values of PBC and PLiBC (<I>r</I> = 0.87; <I>P</I> < 0.001) while the correlation between TBC and PBC (<I>r</I> = 0.65; <I>P</I> < 0.001) and between PLiBC and TBC (<I>r</I> = 0.59; <I>P</I> < 0.001) was on a medium level. The proportional index <I>p<sub>I</sub></I> for PLiBC/PBC was 0.20, for PLiBC/TBC 0.03 and for PBC/TBC 0.16. In seasonal dynamics a statistically significant difference (<I>P</I> < 0.001; <I>P</I> < 0.05) between the increased values of TBC in the summer season was proved compared to the winter and spring season. The differences in the seasonal variation of PBC and PLiBC values were not significant. Experimental investigation of an increase in the values of tested parameters showed that at temperatures of milk sample storage 4 and 6.5°C TBC did not exceed the permissible hygienic value (100 000 CFU/ml) even after 96 hours while at 10°C it amounted to 90 000 CFU/ml after 48 hours and the limit for TBC was exceeded several times after 96 hours. PBC, which is not inhibited by cold storage to such a large extent, did not exceed the hygienic limit value for PBC (50 000 CFU/ml) even after 96 hours when milk samples were stored at 4°C, but at 6.5°C after 72 hours and at 10°C already after 48 hours the values 6 and 20 times higher, respectively, than the hygienic limit were recorded. A similar trend was observed in PLiBC, which exceeded the hazardous limit (43 000 CFU/ml) at 6.5°C after 96 hours and at 10°C already after 48 hours whereas at 4°C the limit value was not exceeded even after 96 hours. The content of FFA also increased in relation to the storage time and temperature of milk samples but in comparison with the increase in the tested groups of microorganisms the increase in FFA showed a higher correlation with storage time compared to storage temperature. A medium correlation was calculated between PLiBC and/or PBC and FFA content (<I>r</I> = 0.52; <I>r</I> = 0.57; <I>P</I> < 0.001).

Milking technology and milk quality

A rapid analysis of bacterial contamination of milk during its production process is performed with the use of the bioluminescence-based ATPmetry method. It is established that, before entering the cooling tank, milk meets top-grade requirements (up to 300 000 CFU/cm3) and in the tank, grade-one.

Evaluation of a Gel Teat Cleaning and Sanitizing Compound for Premilking Hygiene1,2

A gel was developed and tested for cleaning and sanitizing cow teats for milking. Thirty lactating Holstein cows were divided into three groups of 10 each and assigned to three premilking hygiene treatments for 10 wk as follows: 1) cleaning teats with gel, allowing 30s of contact time, and wiping residual gel off with paper towel; 2) washing teats with water and drying them with paper towel; 3) washing teats with water, drying with paper towel, predipping with .5% iodophor solution, allowing 30s of contact time, and drying with paper towel. Individual cow composite milk and teat end swab samples were collected. The gel and predip treatments resulted in less bacterial contamination of milk and teat ends. The gel treatment had an advantage over wash and predip treatments in lower SCC and reduced mastitis. Parlor throughput was greatest for gel and wash treatments. The wash treatment group had highest SCC, bacteria in milk and on teat ends, and mastitis. Milk iodine content was low and similar for the three treatments. Daily milk production and fat and protein percentages were not affected by treatments. The gel treatment was effective, efficient, and provided good hygiene.

The Bacterial Contamination of Milk and Its Significance, by HAROLD BURROW, M.R.C.V.S., D.V.S.M., Chief Veterinary Officer, Birkenhead. (Member.)

The Bacterial Contamination of Milk and Its Significance, by HAROLD BURROW, M.R.C.V.S., D.V.S.M., Chief Veterinary Officer, Birkenhead. (Member.)

Bacterial Contamination of Milk

Bacterial Contamination of Milk