Cell Counts In Raw Milk Research Articles

Bacterial count and somatic cell count in milk from community tanks in Alagoas

Milk is a highly nutritious liquid produced by the mammary glands of cows, serving as a crucial food source for a significant portion of the population. Therefore, ensuring its quality and safety is essential. The purpose of this study is to evaluate the Plate Count and Somatic Cell Count of raw milk from community expansion tanks in the state of Alagoas. For the research, 160 milk samples were collected from mammary quarters in the months of January, February, May, and August 2013, across 23 municipalities covering the three mesoregions of the state of Alagoas. The samples were sent in appropriate containers to the Milk Quality Network Laboratory for Somatic Cell Count (SCC) and Plate Count (PC) analysis. After analysis, it was found that 79.4% (127/160) of the samples met the criteria established by legislation for SCC, while 20.6% (33/160) did not. For PC, 100% (160/160) of the samples were non-compliant with the limits set by legislation. The study highlighted a higher percentage of samples outside the SCC standard in August and the PC with the highest percentage of non-compliance occurring in May. The average SCC and PC for the studied regions showed a significant difference in SCC mean (748,235.3 cells/mL) in the East region, with no significant difference in PC, having the lowest mean (1,853,029.4 CFU/mL) compared to other regions. It was noted that 12.5% of the samples had a fat measurement outside the allowed range, total proteins ranged from 2.4 to 3.86 (g/100g), and the amount of lactose ranged from 3.42 to 5.42 (g/100g). Thus, it can be concluded that all samples were non-compliant with legislation for PC, particularly in the eastern region of the state, indicating issues with the milk extraction, preservation, or cooling process. Implementation of corrective and educational measures is suggested to improve the quality of the product.

Quantitatively determining the somatic cell count of raw milk using dielectric spectra and support vector regression

To investigate the potential of dielectric spectroscopy in quantitatively determining the somatic cell count (SCC) of raw milk, the dielectric spectra of 301 raw milk samples at different SCC were collected using coaxial probe technology in the frequency range of 20 to 4,500 MHz. Standard normal variate, Mahalanobis distance, and joint x-y distances sample division were used to pretreat spectra, detect outliers, and divide samples, respectively. Principal component analysis and variable importance in projection (VIP) methods were used to reduce data dimension and select characteristic variables (CVR), respectively. The full spectra, 16 principal components obtained by principal component analysis, and 86 CVR selected by VIP were used as inputs, respectively, to establish different support vector regression models. The results showed that the nonlinear support vector regression models based on the full spectra and selected CVR using VIP had the best prediction performance, with the standard error of prediction and residual predictive deviation of 0.19 log SCC/mL and 2.37, respectively. The study provided a novel method for online or in situ detection of the SCC of raw milk in production, processing, and consumption.

A vision-based instrument for measuring milk somatic cell count

The method of rapidly measuring the somatic cell count of raw milk is important for detecting the quality of milk and monitoring the health of dairy cows. This paper investigates a vision-based measurement algorithm and develops an instrument for measuring the somatic cell count. In detail, first, microscopic images of glass slides are automatically captured. Second, the Hough transform is used to calibrate the microscopic image so as to compute the sample volume. Third, a discrete optimization model is set up to determine the image segmentation threshold. Fourth, the features of milk somatic cell are expressed in area, ratio of length to width and circularity. The least-square circle method is employed to detect the circularity of the milk somatic cell. Then, an automatic milk somatic cell count is achieved via a recursion algorithm. Finally, a milk somatic cell counting instrument is developed based on the proposed algorithm, which is verified to be applicable via comparison with the FossMatic 5000, made in Denmark.

Does physical state of farm housing and milking practices affect total bacteria and somatic cell count of cow milk?

AbstractThe study determined the effect of physical state of farm housing on total bacteria and somatic cell count (SCC) of cow milk. Milk records collected at Dairy Services Zimbabwe were used. Effects of physical state of ceilings, doors, ventilation, walls, drains, fly‐proofs, windows and roof type on total bacterial count (TBC) in milk, and SCC were determined using general linear models procedure. Poor physical state of ceilings, doors and floors in milking parlors, wash rooms and bulk tank rooms result in high TBC and SCC in milk (p < 0.05). Poor ventilation in the bulk tank room results in high TBC in milk (p < 0.05). Floors, doors, and ceilings of milking houses should be kept in sound condition and good repair in order minimize TBC and SCC in raw milk.Practical applicationsUnderstanding how physical state of farm houses and management practices affect total bacterial count and somatic cell count in fresh milk enables farmers and regulatory agencies to put in corrective action to reduce bacterial contamination of milk at farm level. This helps keep the population of disease causing bacteria in raw milk, which is widely consumed by human beings, as low as possible. It also helps reduce contamination by some resistant bacteria that might survive processing and cause further defects in milk products. The shelf‐life of the milk and its products is, thus, improved. Reducing bacterial and somatic cell count in raw milk also helps the milk producers to score high milk grades on the market and, thus, fetch high prices.

Validation of the BetaStar® Advanced for Beta-lactams Test Kit for the Screening of Bulk Tank and Tanker Truck Milks for the Presence of Beta-lactam Drug Residues.

A validation study was conducted for an immunochromatographic method (BetaStar® Advanced for Beta-lactams) for the detection of beta-lactam residues in raw, commingled bovine milk. The assay detected amoxicillin, ampicillin, cloxacillin, penicillin, cephapirin, and ceftiofur below the U.S. Food and Drug Administration tolerance levels but above the maximum sensitivity thresholds established by the National Conference on Interstate Milk Shipments. The results of internal and independent laboratory dose-response studies employing spiked samples were in agreement. The test detected all six drugs at the approximate 90/95% sensitivity levels in milk from cows treated with each drug. Selectivity of the assay was 100%, as no false-positive results were obtained in testing 1148 control milk samples. Testing the estimated 90/95% sensitivity level for amoxicillin (8.5 ppb), ampicillin (6.9 ppb), cloxacillin (8.9 ppb), penicillin (4.2 ppb), and cephapirin (17.6 ppb), and at 100 ppb for each antibiotic, resulted in 94-100% positive tests for each of the beta-lactam drugs. The results of ruggedness experiments established the operating parameter tolerances for the assay. Cross-reactivity testing established that the assay detects other certain beta-lactam drugs, but it does not cross-react with any of 30 drugs belonging to seven different drug classes. Abnormally high bacterial or somatic cell counts in raw milk produced no assay interference.

Effect of milk centrifugation and incorporation of high-heat-treated centrifugate on the composition, texture, and ripening characteristics of Maasdam cheese

This study investigated the effect of centrifugation (9,000 × g, 50°C, flow rate = 1,000 L/h), as well as the incorporation of high-heat-treated (HHT) centrifugate into cheese milk on the composition, texture, and ripening characteristics of Maasdam cheese. Neither centrifugation nor incorporation of HHT centrifugate into cheese milk had a pronounced effect on the compositional parameters of any experimental cheeses, except for moisture and moisture in nonfat substance (MNFS) levels. Incorporation of HHT centrifugate at a rate of 6 to 10% of the total milk weight into centrifuged milk increased the level of denatured whey protein in the cheese milk and also increased the level of MNFS in the resultant cheese compared with cheeses made from centrifuged milk and control cheeses; moreover, cheese made from centrifuged milk had ∼3% higher moisture content on average than control cheeses. Centrifugation of cheese milk reduced the somatic cell count by ∼95% relative to the somatic cell count in raw milk. Neither centrifugation nor incorporation of HHT centrifugate into cheese milk had a significant effect on age-related changes in pH, lactate content, and levels of primary and secondary proteolysis. However, the value for hardness was significantly lower for cheeses made from milk containing HHT centrifugate than for other experimental cheese types. Overall, centrifugation appeared to have little effect on composition, texture, and ripening characteristics of Maasdam cheese. However, care should be taken when incorporating HHT centrifugate into cheese milk, because such practices can influence the level of moisture, MNFS, and texture (particularly hardness) of resultant cheeses. Such differences may have the potential to influence subsequent eye development characteristic, although no definitive trends were observed in the present study and further research on this is recommended.

<b>Evolution and factors influencing somatic cell count in raw milk from farms in Viçosa, state of Minas Gerais

The somatic cell count (SCC) of refrigerated raw milk reflects the occurrence of mastitis in the herd and the management of rural property. Therefore, this study aimed to evaluate the SCC of the refrigerated raw milk and its determinant factors in dairy properties of Viçosa, State of Minas Gerais. Monthly, milk samples were taken from 44 cooling tanks during 2012. A structured questionnaire was applied to evaluate the production and management characteristics of the herds. There was a significant variation (p < 0.05) in the mean SCC of the milk, which was lower from June to August. Higher mean SCC and percentages of samples above the limit set by the legislation were observed in months of higher rainfall and ambient temperature (p < 0.05). Mechanical milking, lower milk yield, productivity, inadequate milking procedures, equipment hygiene, and water quality were all factors that influenced (p < 0.05) the SCC of raw refrigerated milk. Milker training is required for production of low SCC milk.

Probabilistic comparison and assessment of proficiency testing schemes and laboratories in the somatic cell count of raw milk

The somatic cell count (SCC) of milk is one of the main indicators of the udder health status of lactating mammals and is a hygiene criterion of raw milk used to manufacture dairy products. An increase in SCC is regarded as one of the primary indicators of inflammation of the mammary gland. Therefore, SCC is relevant in food legislation as well as in the payment of ex-farm raw milk and it has a major impact on farm management and breeding programs. Its determination is one of the most frequently performed analytical tests worldwide. Routine measurements of SCC are almost exclusively done using automated fluoro-opto-electronic counting. However, certified reference materials for SCC are lacking, and the microscopic reference method is not reliable because of serious inherent weaknesses. A reference system approach may help to largely overcome these deficiencies and help to assure equivalence in SCC worldwide. The approach is characterised as a positioning system fed by different types of information from various sources. A statistical approach for comparing proficiency tests (PTs) by assessing them using a quality index P Q and assessing participating laboratories using a quality index P L, both deriving from probabilities, is proposed. The basic assumption is that PT schemes are conducted according to recognised guidelines in order to compute performance characteristics, such as z-scores, repeatability and reproducibility standard deviations. Standard deviations are compared with the method validation data from the ISO method. Input quantities close to or smaller than the reference data of the method validation or the assigned value of the PT result in values for P Q and P L close to the maximum value. Evaluation examples of well-known PTs show the practicability of the proposed approach.

Development of electrochemical method to detect bacterial count, Listeria monocytogenes, and somatic cell count in raw milk

Bacterial count, Listeria monocytogenes detection and somatic cell count (SCC) are generally recognized as indexes of raw milk quality which could affect the price and the shelf-life of dairy products. This research was aimed at developing an easy, low-cost and rapid quantitative electrochemical detection method for measuring the three indexes simultaneously. Through the electrochemical sensor, bacterial count or L. monocytogenes detection was determined by evaluating the electric-current originated from microbial activity. SCC was determined by measuring current signal produced by the expression of lactate dehydrogenase (LDH) activity, a biomarker also for diagnosing mastitis. The research indicated that the appropriate conditions for applying the biosensor to bacterial count detection ranging from 102 to 108 CFU/ml within detection time (DT) of 1–10h are 35°C at 1V and that the optimal conditions for L. monocytogenes detection are 37°C at 1V, under pH 9.4, associated with a Fraser selective broth. The optimal conditions for SCC detection ranging from 350 to 780 thousand SCC/ml (R2=0.907) within 60s (DT) are 42°C at 0.5V, under pH 9.0. The biosensor is shown to be a promising approach for the detections in raw milk.

Monitoring Milk Somatic Cell Counts

The presence of somatic cells in milk is a widely disputed issue in milk production sector. The somatic cell counts in raw milk are a marker for the specific cow diseases such as mastitis or swollen udder. The high level of somatic cells causes physical and chemical changes to milk composition and nutritional value, and as well to milk products. Also, the mastitic milk is not proper for human consumption due to its contribution to spreading of certain diseases and food poisoning. According to these effects, EU Regulations established the maximum threshold of admitted somatic cells in raw milk to 400000 cells / mL starting with 2014. The purpose of this study was carried out in order to examine the raw milk samples provided from small farms, industrial type farms and milk processing units. There are several ways to count somatic cells in milk but the reference accepted method is the microscopic method described by the SR EN ISO 13366-1/2008. Generally samples registered values in accordance with the admissible limit. By periodical monitoring of the somatic cell count, certain technological process issues are being avoided and consumer’s health ensured.

Validation Study of the BetaStar® Plus Lateral Flow Assay for Detection of Beta-Lactam Antibiotics in Milk

A validation study designed to meet the requirements of the AOAC Research Institute and the U.S. Food and Drug Administration, Center for Veterinary Medicine (FDA/CVM) was conducted for a receptor and antibody-based, immunochromatographic method (BetaStar Plus) for detection of beta-lactam antibiotic residues in raw, commingled bovine milk. The assay was found to detect amoxicillin, ampicillin, ceftiofur, cephapirin, cloxacillin, and penicillin G at levels below the FDA tolerance/safe levels, but above the maximum sensitivity thresholds established by the National Conference on Interstate Milk Shipments (NCIMS). Results of the part I (internal) and part II (independent laboratory) dose-response studies employing spiked samples were in close agreement. The test was able to detect all six drugs at the approximate 90/95% sensitivity levels when presented as incurred residues in milk collected from cows that had been treated with the specific drug. Selectivity of the assay was 100%, as no false-positive results were obtained in testing of 1031 control milk samples. Results of ruggedness experiments established the operating parameter tolerances for the BetaStar Plus assay. Results of cross-reactivity testing established that the assay detects certain other beta-lactam drugs (dicloxacillin and ticarcillin), but it does not cross-react with any of 30 drugs belonging to other classes. Abnormally high bacterial or somatic cell counts in raw milk produced no interference with the ability of the test to detect beta-lactams at tolerance/safe levels.

Microbiological analysis and somatic cell counts in raw milk from farms of São Paulo State, Brazil

The objective of the study was to evaluate mesophyle, psychrotroph and somatic cell counts (SCC), and presence of Staphylococcus aureus in raw milk produced in 42 dairy farms of the State of Sao Paulo. Farms were classified according to milk yield in low ( 1,000 L/day, n = 17). Mesophylic bacteria counts were lower (p 0.05) in psychrotrophic and somatic cell counts between the three categories. S. aureus was more frequent (p < 0.05) in the milk of individual cows in intermediate production farms. Percentage of samples that did not comply with SCC tolerance limits in grade B milk ranged from 29.4 (low production) to 52.9% (high production). Results indicate that the greatest difficulties for dairy farms to comply with milk quality parameters are related to the adoption of hygiene practices during milking and to failures in milk conservation. Key words: Milk quality, mesophyles, psychrotrophs, somatic cell counts (SCC),Staphylococcus aureus.

Validation Study of a Receptor-Based Lateral Flow Assay for Detection of Beta-Lactam Antibiotics in Milk

A validation study designed to meet the requirements of the AOAC Research Institute and the U.S. Food and Drug Administration (FDA), Center for Veterinary Medicine, was conducted for a receptor-based, immunochromatographic method (BetaStar US) for detection of beta-lactam antibiotic residues in raw, commingled bovine milk. The assay was found to detect amoxicillin, ampicillin, cephapirin, cloxacillin, and penicillin G at levels below the FDA tolerance/safe levels but above the maximum sensitivity thresholds established by the National Conference on Interstate Milk Shipments. Results of the Part I (internal) and Part II (independent laboratory) dose-response studies using spiked samples were in very close agreement for all five drugs tested, with differences between the Part I and Part II 90/95% sensitivity values ranging from 0 to 1 ppb. The test was able to detect all five drugs at the approximate 90/95% sensitivity levels when present as incurred residues in milk collected from cows that had been treated with the specific drug. A sixth drug, ceftiofur, was found to be undetectable at levels of < or = 500 ppb (as total ceftiofur metabolites from incurred residues in milk samples). The selectivity of the assay was 100%, because no false-positive results were obtained in tests of >1000 control milk samples. The assay was found to be applicable to the testing of frozen raw milk samples. Results of ruggedness experiments established the operating parameter tolerances for the BetaStar US assay. Results of cross-reactivity testing established that the assay detects certain other beta-lactam drugs (dicloxacillin and ticarcillin), but it does not cross-react with any of 30 drugs belonging to other classes. Abnormally high bacterial or somatic cell counts in raw milk produced no interference with the ability of the test to detect beta-lactams at tolerance/safe levels.

Cylindrical standing wave resonator for liquid food quality control.

In this paper, an innovative technology based on the use of ultrasonic cylindrical standing waves for continuous monitoring of quality of various liquid food products, such as milk, juices, beer, wine, and drinking water is described. A proprietary unique feature of the developed ultrasonic analyzer is that it employs a combined mode of operation using both high-intensity and low-frequency (10 W/cm2, 1 MHz) waves for separation and concentration of the high-molecular-weight particles (fat globules or cells) and low-intensity and high-frequency (0.5 W/cm2, 10 MHz) waves for compositional analysis. High accuracy for ultrasound velocity measurements (up to 0.001%) and ultrasound attenuation (of about 1%) and rapid testing time (2–20 s) have been achieved. Comparative analyses of the ultrasonic method with standard reference techniques have produced linear calibration curves for major components with correlation coefficients higher than 0.95. It is thus possible to monitor total protein and fat content, and somatic cell count in raw milk in cowsheds, or salinity, turbidity, specific gravity, and particles (bacteria) in drinking water directly. Advantages of the proposed technology include the reagent-free nature, no need for sample pretreatment, ease-of-use, and low cost.

Improved bioluminescent assay of somatic cell counts in raw milk

Somatic cell count (SCC) in milk is considered to be a valuable indicator of cow mastitis. For assessment of SCC in milk, the bioluminescent assay based on determination of ATP from somatic cells ([ATPsom]) in milk was proposed earlier. However, this assay is still not widely used in practice owing to lower reliability compared with conventional methods such as direct microscopy and flow cytometry. We revised the bioluminescent SCC assay and developed a simple protocol based on determination of the total non-bacterial ATP concentration in milk. It was shown that the novel ATP-releasing agent Neonol-10 (oxy-ethylated iso-nonyl phenol) has superior performance providing 100% lysis of somatic cells while not disrupting bacterial cells of milk at a concentration of 1.5% w/w. There was high correlation (R2=0.99) between measured bioluminescence and SCC as measured by direct microscopy. The observed detection limit of the bioluminescent milk SCC assay was as low as 900 cell/ml, time of analysis was 2-3 min per sample. The proposed method has high potential for on-site mastitis diagnostics.

Recent Trends in Somatic Cell Counts in Raw Milk

Recent Trends in Somatic Cell Counts in Raw Milk

Disinfection in the dairy parlour.

The dairy farmer has the responsibility of producing milk under clean and hygienic conditions, employing appropriate techniques to clean and disinfect the milking equipment and the milking parlour. The ability of raw milk to retain its quality under storage, and the safety of the product for the consumer, can both be directly related to the bacterial content of the milk. In most countries, bacterial content is one of the factors considered in determining the level of payment for milk. Cleaning and disinfection are complementary processes: neither process alone will achieve the desired end result. Milk with low bacterial and somatic cell counts cannot be produced unless milking equipment is effectively cleaned and disinfected between milkings and the cows are kept healthy. The author considers the various sources of bacterial contamination and increased somatic cell counts in raw milk, and describes the cleaning and disinfection practices recommended for the production of milk of good microbiological quality.

A Collaborative Study of the Microtiter Count Method and Standard Plate Count Method for Viable Cell Count of Raw Milk

The Microtiter Count method was compared with the Standard Plate Count (SPC) method in four different laboratories. An unamended as well as a modified procedure were used. Statistical analysis showed that at the 95% confidence limit the amended procedure was reliable compared with the SPC for making a viable cell count of raw milk. The Microtiter Count method was credited with savings of time, space, and material. However, the operator needs some practice and comparative testings before using the method for routine analysis.