Quantitative assessment of bacterial contamination of raw milk using bioluminescence

1999 ◽  
Vol 66 (4) ◽  
pp. 627-631 ◽  
Author(s):  
LUBOV Yu. BROVKO ◽  
VALERY G. FROUNDJIAN ◽  
VERONIKA S. BABUNOVA ◽  
NATALYA N. UGAROVA
Keyword(s):  
Bacterial Contamination ◽  
Bacterial Count ◽  
Raw Milk ◽  
Total Bacterial Count ◽  
Bacterial Cells ◽  
Atp Assay ◽  
Atp Bioluminescence ◽  
Living Organisms ◽  
Quality Of Milk

Enumeration of bacteria in raw milk is of public health and economic importance. Among the proposed rapid methods for assessment of bacterial contamination in raw milk, ATP bioluminescence has proved to be one of the most promising (Griffiths, 1991). Several companies produce ATP bioluminescence reagent kits and equipment for analysing raw milk samples for total bacterial count (Sutherland et al. 1994; Reybroeck & Schram, 1995). The principle of ATP bioluminescent bacterial assay is based on the following assumptions (Olsen, 1991). All living organisms contain ATP, ATP is neither associated with dead cells nor absorbed on to surfaces, colloids and so on, and there is a fairly constant ratio of ATP to biomass/number of cells for all microbial taxa independent of metabolic activity or environmental conditions. Of these assumptions, only the first seems to be indisputable. It is not the number of bacterial cells, but rather the colony forming unit (cfu) that is the denomination used when assessing the microbial quality of milk. For Gram-negative rods of the genus Enterobacteriaceae, a cfu is usually derived from a single cell. However, Gram-positive cocci (staphylococci and streptococci) grow in bunches and chains respectively (Gregg, 1991), and estimation of cell numbers may not give good agreement with the colony counts.Several approaches have been investigated to increase the sensitivity of the bioluminescent method (Pahuski et al. 1991; Sutherland et al. 1994; Reybroeck & Schram, 1995; Froundjian et al. 1999). Although the detection limit achieved by these modifications (104 cfu/ml) may be sufficient for practical use (Bautista et al. 1992; Reybroeck & Schram 1995), the accuracy of the analysis was not significantly improved. The reported values for accuracy of the estimate for cfu/ml in raw milk (Syx) by the bioluminescent method were in the range 0·27–0·87 log units (Bautista et al. 1992; Reybroeck & Schram, 1995). The purpose of the present study was to determine the reasons for the lack of accuracy of the bacterial ATP assay in raw milk.

scholarly journals Keeping Quality of Milk and the Age on Testing for Total Bacterial Count

1931 ◽  
Vol 31 (3) ◽  
pp. 373-374 ◽  
Author(s):  
H. Barkworth
Keyword(s):  
Bacterial Count ◽  
Total Bacterial Count ◽  
Keeping Quality ◽  
Quality Of Milk

During the period 1923–29 inclusive nearly six thousand samples of milk were tested at Wye for both total bacterial count and also keeping quality. An examination of the results shows that on the average the afternoon milks showed nine hours less keeping quality than morning milks of the same total bacterial count, see Table I. The age of the milk on testing for total bacterial count (reckoned from the time of milking) is 27–29 hours for morning milks and 20–24 hours for afternoon milks.

scholarly journals Chilled raw milk quality: a case study in Zona da Mata region, Minas Gerais State, Brazil

2020 ◽  
Vol 50 (4) ◽  
Author(s):  
Luiz Paulo de Lima ◽  
Gustavo Bastos Braga ◽  
Ronaldo Perez ◽  
Antonio Fernandes de Carvalho
Keyword(s):  
Bacterial Count ◽  
Raw Milk ◽  
Milk Composition ◽  
Minas Gerais ◽  
Milk Quality ◽  
Total Bacterial Count ◽  
Improvement Program ◽  
Minas Gerais State

ABSTRACT: This paper aimed to analyze the evolution of the quality of raw milk produced by producers in the Zona da Mata region, in the state of Minas Gerais, between 2012 and 2018. For this purpose, we used the linear mixed-effects model to analyze the monthly evolution of the results of milk composition indicators (fat, protein, and defatted dry extract - DDE), somatic cell count - SCC, and total bacterial count - TBC, from the official monthly registry of 94 milk producers, suppliers of a region’s dairy. Results indicate a continuous reduction in the milk composition indicators between 2014 and 2018. For the SCC and TBC indicators, we identified only one-off reductions. The supply of a larger volume of milk was associated with increased TBC. Seasonality influenced all quality indicators analyzed. According to these results, we concluded that the analyzed quality of chilled raw milk offered by producers was proven worse from 2012 to 2018, despite the actions implemented by the National Milk Quality Improvement Program - PNMQL.

Total Bacterial Count in Raw Milk Using the BactoScan 8000

1993 ◽  
Vol 76 (4) ◽  
pp. 838-841 ◽  
Author(s):  
J L Rodrίguez-Otero ◽  
M Hermtoa ◽  
A Cepeda ◽  
C Franco
Keyword(s):  
Reference Method ◽  
Petri Dish ◽  
Bacterial Count ◽  
Raw Milk ◽  
Total Bacterial Count ◽  
Milk Samples ◽  
Colony Forming Units ◽  
Milk Hygiene ◽  
The Individual

Abstract The BactoScan 8000 (Foss Electric) automatically performs a total count of bacteria in raw milk. It was designed for fast, repeatable counting. The apparatus counts the individual bacteria (IBC) instead of colony forming units (CFU). IBC provides more information on the state of milk hygiene than the CFU count. The repeatability, sr, was 0.033 log (IBC/μL), which is equivalent to a coefficient of variation of 7.9% (IBC/μL). The carryover, which is the contamination one sample imposes on the next, was 0.19%. The BactoScan 8000 was calibrated against the reference method of counting colonies on a Petri dish. The correlation coefficient for 429 milk samples was r= 0.88, and the standard deviation of the residuals, syx, was 0.259. The detection limit was 15 CFU/μL. We recommend establishing a system of payment to farmers based on the bacteriological quality of their milk as determined by the BactoScan 8000. Because results are obtained in IBC/μL, analytical differences resulting from conversion to CFU/|iL are eliminated.

scholarly journals Total Bacterial Counts of Raw Milk in Eastern Terai of Nepal

2010 ◽  
Vol 11 ◽  
pp. 46-50 ◽  
Author(s):  
Lekh Raj Dahal ◽  
Dainik B Nepali Karki ◽  
Ramashish Shah
Keyword(s):  
Experimental Period ◽  
Bacterial Count ◽  
Raw Milk ◽  
Total Bacterial Count ◽  
Bacteriological Study ◽  
Farm Level ◽  
International Standard ◽  
Milk Samples ◽  
Plant Level

This study was carried out to evaluate the quality of raw milk measured by Total Bacterial Count (TBC). Bulk raw milk for bacteriological study was carried out in Regional Veterinary Laboratory (RVL), Biratnagar. Altogether, 520 milk samples for TBC were examined at farm and plant levels. Results showed a great variability of TBC for the overall study period. The lowest TBC (2.78 x 106) and the highest TBC (13.299 x 106) at two milk collection units revealed nearly fivefold difference. The results of mean TBC at farm (9.03 x 105) was nine fold of international standard (1 x 105), and mean TBC at plant (104.71 x 105) reached 104 folds the international standard. The TBC at farm level were non significant (P>0.05) for overall experimental period where as most of TBC at plant level differed (p<0.01) significantly. TBC at farm level differed significantly (P<0.01) from each record of same date at plant level. The highest number of TBC (16.5 x 106) was observed in the month of September, which was significantly (P <0.01) different from the rest of the months. The results obtained from the study indicated that the current situation is critical and needs real improvement from production point to processing plant.Key words: Raw milk; Total Bacterial Count (TBC)The Journal of AGRICULTURE AND ENVIRONMENTVol. 11, 2010Page: 46-50Uploaded Date: 15 Septembre, 2010

scholarly journals The extended methylene blue reduction test and milk quality

2020 ◽  
Vol 8 (1) ◽  
pp. 140-148 ◽  
Author(s):  
Mayra Pérez-Lomas ◽  
Milton J. Cuaran-Guerrero ◽  
Lucía Yépez-Vásquez ◽  
Holger Pineda-Flores ◽  
Jimmy Núñez-Pérez ◽  
...  
Keyword(s):  
Methylene Blue ◽  
Bacterial Count ◽  
Milk Quality ◽  
Total Bacterial Count ◽  
Reduction Test ◽  
Fresh Milk ◽  
Methylene Blue Reduction ◽  
Cheap Method ◽  
Quality Of Milk

Introduction. This study aimed to evaluate the quality of milk produced by six cattlemen’s associations in small, isolated farming communities of Carchi, Ecuador. It involved a herd of 814 cows and lasted eight consecutive months. Another aim was to propose a suitable methodology for milk quality evaluation. Study objects and methods. All milk samples were analyzed for total solids, protein, fat, acidity, density, total bacterial count (TBC) and somatic cell count (SCC). Each sample was subjected to an extended qualitative methylene blue reduction test (MBRTe) for which 10 mL of milk, with 0.5 mL of methylene blue, was incubated at 37°C for 24 h. Results and discussion. As a result, we obtained the following types of clots: MBRTe-I (homogeneous solid/liquid clot), MBRTe-II (lumpy clot), MBRTe-III (gaseous clot) and MBRTe-IV (lumpy + gaseous clot). The study showed significant differences in the quality of milk between different associations, suggesting that some of them did not comply with good practices of milking, handling and storage of fresh milk. The quality of milk was classified as good in one association, as regular in another association, and as low in four associations. The MBRTe classified 37% of the samples as MBRTe-I, 18% as MBRTe-II, 14% as MBRTe-III and 12% as MBRTe-IV. Of the MBRTe-I samples, 95% showed the TBC and SCC values of first quality milk. The MBRTe-II had the TBC values of first quality milk, but exceeded the SCC, while the MBRTe-III had good SCC values, but exceeded the TBC. Finally, the MBRTe-IV samples exceeded the permissible levels of both TBC and SCC. Conclusion. It was proved that the MBRTe can help milk producers evaluate the quality of milk and alert them to the possible presence of mastitis in the herd. The MBRTe is a reliable and cheap method that is quick and easy to perform.

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

2019 ◽  
Vol 5 (1) ◽  
pp. 31-36
Author(s):  
Asma Talukder ◽  
Anuja Saha ◽  
Sabrina Binta Shoeb ◽  
Mimma Tabassum
Keyword(s):  
Water Samples ◽  
Bacterial Contamination ◽  
Microbiological Quality ◽  
Bacterial Count ◽  
Raw Milk ◽  
Daily Basis ◽  
Total Coliform ◽  
Milk Samples ◽  
Mold Count

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. Asian J. Med. Biol. Res. March 2019, 5(1): 31-36

scholarly journals CONTAGEM DE CÉLULAS SOMÁTICAS, CONTAGEM BACTERIANA TOTAL E ANÁLISES FÍSICO-QUÍMICAS DO LEITE PRODUZIDO NA REGIÃO SUL DO ESTADO DE GOIÁS

2017 ◽  
Vol 13 (Especial 2) ◽  
pp. 135-141
Author(s):  
Nariane Coelho de Oliveira ◽  
Milena de Lima Vieira ◽  
Wallacy Barbacena Rosa dos Santos ◽  
Aline Sousa Camargos ◽  
Jeferson Corrêa Ribeiro ◽  
...  
Keyword(s):  
Total Protein ◽  
Experimental Period ◽  
Bacterial Count ◽  
The State ◽  
Total Bacterial Count ◽  
Dairy Herds ◽  
Physicochemical Composition ◽  
Physical Chemical ◽  
Quality Of Milk

Considering that the production of milk in the State of Goiás has undergone changes in the productive chain that reflect directly in the national scenario, studies are needed to obtain information on the quality of milk produced in this region. The present work was carried out in partnership with the cooperative receiving the milk production of the rural properties studied. The objective of this study was to evaluate the incidence of somatic cell count (CCS), total bacterial count (CBT) and the physicochemical composition of dairy herds in the southern region of the state of Goiás. The data of CCS, CBT and physicochemical analyzes were tabulated, from of period of August of 2015 to July of 2016. The samples were collected monthly in the cooling pond of the farms and sent to a laboratory accredited by the Brazilian Quality Milk Network (RBQL). High values were found in the CCS, however, remaining within the limits allowed by Normative Instruction 62. For CBT were found alarming results, as they were indexed beyond what is allowed by the regulation. Regarding the physical-chemical composition variables, this study were used 136 Colloquium Agrariae, vol. 13, n. Especial 2, Jan–Jun, 2017, p. 135-141. ISSN: 1809-8215. DOI: 10.5747/ca.2017.v13.nesp2.000219 lactose, fat and total protein. Comparing the results obtained during the experimental period with those of Normative Instruction 62, were observed that the total protein and fat contents are within the established standard.

scholarly journals EVALUASI CEMARAN BAKTERI PADA SUSU DI TINGKAT PETERNAK, LOPER, DAN KUD DI KECAMATAN GETASAN KABUPATEN SEMARANG

MEDIAGRO ◽  
2019 ◽  
Vol 14 (2) ◽  
Author(s):  
Any Widiyastuti ◽  
Dian Wahyu Harjanti ◽  
Bhakti Etza Setiani
Keyword(s):  
Positive Result ◽  
Bacterial Contamination ◽  
Microbiological Quality ◽  
Bacterial Count ◽  
Fresh Milk ◽  
Milk Contamination ◽  
Dairy Cooperatives ◽  
Quality Of Milk ◽  
Total Bacteria

This research was conducted to evaluate the bacterial contamination in fresh milk from farmers, milk collectors, and dairy cooperative (KUD) in Getasan Subdistrict, Semarang Regency. The evaluation of bacterial contamination has been observed by the number of bacteria, milk distribution time, reductation test, alcohol test and pH test of fresh milk samples which had been taken from 30 farmers, 30 milk collectors and 4 dairy cooperatives in Getasan Subdistrict. The result showed that in the farmers, there is 1 positive alcohol test from 30 samples, pH 6, reductation time of 7 hours, and has total bacteria 3.01 × 105 cfu / ml milk. The alcohol test of the milk from collectors also show 1 positive result from 30 samples with pH 6, reduction time of 6 hours and has total bacteria 6.17 × 105 cfu / ml milk. While in alcohol test of dairy cooperative shows 2 positive result, from 4 samples with pH 6, reductation time of 5 hours and has total bacteria 1.38 × 106 cfu / ml milk. The duration of milk distribution from farmer to KUD were 111 minutes. Thus, it is concluded that microbiological quality of milk in farmers and milk collectors level is good because it is below the maximum limit of total bacteria according to Indonesian Standart, but the amount of bacteria milk contamination in dairy cooperative is high due to the duration of distribution (111 minutes) without cooling.Keywords: bacterial count, milk quality, milk safety, distribution time

scholarly journals PARÂMETROS DE QUALIDADE DO LEITE CRU FORNECIDO PARA INDÚSTRIA DE PROCESSAMENTO DE PRODUTOS LÁCTEOS

2017 ◽  
Vol 13 (Especial 2) ◽  
pp. 372-380
Author(s):  
Franciele Ávila Garcia ◽  
Vania Silva Carvalho ◽  
Nayana Ribeiro Soares ◽  
Suzane Martins Ferreira
Keyword(s):  
Somatic Cell ◽  
Cell Count ◽  
Somatic Cell Count ◽  
Geometric Mean ◽  
Bacterial Count ◽  
Raw Milk ◽  
Total Bacterial Count ◽  
Chemical Contamination ◽  
Physical And Chemical

Milk quality is defined by parameters of physical, chemical, sensory, low bacterial count, absence of pathogens, low somatic cell count, absence of chemical preservatives and antibiotic residues. These residues treat If a chemical contamination in milk and pose risks to public health and damage to the processing of dairy industry because there is no technological treatment that can inactivate them. So aim with this study was to evaluate the quality of the raw milk used in a dairy processing industry of Goiás state southern region related to antibiotic parameters, fat, lactose, protein, total dry layer (EST), dry layer degreased (ESD), somatic cell count (SCC) and total bacterial count (TBC) of four producers in the period from August to October 2015 were evaluated 55 samples, which showed 7.3% of residues of betalactam antibiotics detected for producer A. the average statistics at odds with the standards established by Instruction No. 62 were perceived to producer a with 8.18% of ESD, 42.64 x 105 CS / mL of CCS and 13.26 x 105 CFU / mL CBT. The geometric mean of CCS producers A and C also did not attend the IN 62 to values 37.42 x 105 CS /mL and 6.69 x 105 CS/mL respectively. It was observed that the SCC may indicate the presence of infection in animals and promote physical and chemical changes in the milk impairs its quality and consequently milk derivatives.

Proteinase and phospholipase activities and development at different temperatures of yeasts isolated from bovine milk

2011 ◽  
Vol 78 (4) ◽  
pp. 385-390 ◽  
Author(s):  
Priscilla A Melville ◽  
Nilson R Benites ◽  
Monica Ruz-Peres ◽  
Eugenio Yokoya
Keyword(s):  
Dairy Products ◽  
Room Temperature ◽  
Bovine Milk ◽  
Raw Milk ◽  
Pathogenic Potential ◽  
Proteinase Production ◽  
Different Temperatures ◽  
Quality Of Milk ◽  
Means Of Transmission

The presence of yeasts in milk may cause physical and chemical changes limiting the durability and compromising the quality of the product. Moreover, milk and dairy products contaminated by yeasts may be a potential means of transmission of these microorganisms to man and animals causing several kinds of infections. This study aimed to determine whether different species of yeasts isolated from bovine raw milk had the ability to develop at 37°C and/or under refrigeration temperature. Proteinase and phospholipase activities resulting from these yeasts were also monitored at different temperatures. Five genera of yeasts (Aureobasidium sp., Candida spp., Geotrichum spp., Trichosporon spp. and Rhodotorula spp.) isolated from bovine raw milk samples were evaluated. All strains showed one or a combination of characteristics: growth at 37°C (99·09% of the strains), psychrotrophic behaviour (50·9%), proteinase production (16·81% of the strains at 37°C and 4·09% under refrigeration) and phospholipase production (36·36% of the isolates at 37°C and 10·9% under refrigeration), and all these factors may compromise the quality of the product. Proteinase production was similar for strains incubated at 37°C (16·81% of the isolates) and room temperature (17·27%) but there was less amount of phospholipase-producing strains at room temperature (15·45% of the isolates were positive) when compared with incubation at 37°C (36·36%). Enzymes production at 37°C by yeasts isolated from milk confirmed their pathogenic potential. The refrigeration temperature was found to be most efficient to inhibit enzymes production and consequently ensure better quality of milk. The viability of yeasts and the activity of their enzymes at different temperatures are worrying because this can compromise the quality of dairy products at all stages of production and/or storage, and represent a risk to the consumer.

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