Twelve different liquid market milks of Bangladesh were examined to evaluate their chemical and sanitary quality. Six of these were open raw milk bought from local daily markets and the other six were processed packet milk (both pasteurized and UHT [Ultra High Temperature]-processed) available in shops. The twelve samples were examined for the determination of percentage of water, total soluble solids (TSS), fat, solids-non-fat (SNF), lactose, protein, and ash; measurement of titratable acidity; detection of adulterants; enumeration of total bacterial count, staphylococcal, coliform, fecal coliform, Salmonella and Shigella, Aeromonas hydrophila, and psychrophilic count. Results revealed that most of the raw and pasteurized milks were substandard in both chemical and sanitary quality whereas the quality of UHT-treated milks was excellent. Majority of the raw and pasteurized milks contained fair amounts of lactose, protein and ash, but a number of these had lesser amount of fat. All the raw and pasteurized milks were found to be contaminated with bacterial loads exceeding the acceptable limit. The indicator organisms ie coliforms and fecal coliforms were present in most of these samples in large numbers. Pathogenic bacterial genera (Aeromonas, Salmonella, and Staphylococcus) were also identified in some of these. High counts of psychrophilic bacteria were also found in the raw and pasteurized milk. But none of the UHT-processed milks contained any bacteria. Water had been added to five raw and one pasteurized milk whereas sucrose was found in five of the six heat-treated samples.
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
Study on physicochemical and microbial quality of available raw, pasteurized ...IJSIT Editor
Milk is a very popular drink in Bangladesh. This study was conducted to evaluate the microbial
content of milk during preservation and to make a suitable decision on the effect of preservation on the
microbial population in milk. Major tests considered in the research work were titratable acidity, COB test,
total viable bacteria count (TVC) and Coliform count. The initial average TVC in raw milk was 5.49±0.69 log
c.f.u. /ml. which increased to 6.25±0.10 log c.f.u. /ml. indicated deterioration in milk quality. In case of
pasteurized milk samples initial average total viable count was 4.43±0.17 log. c.f.u. /ml. increased to
5.92±0.05 log c.f.u. /ml. after six days of preservation. UHT milk samples which should not contain microbial
contamination also provided with initial average total viable count of 3.32±0.06 log c.f.u. /ml. and 3.59±0.04
log c.f.u. /ml. during preservation at room temperature for four months. Coliform bacteria usually cannot
survive at the pasteurization temperature .The initial average coliform bacteria were estimated 3.55±0.12 log
c.f.u. /ml. and 2.08±0.11 log c.f.u. /ml. for pasteurized and UHT milk samples which increase to 3.81±0.06 log.
c.f.u. /ml. for pasteurized milk after six days of preservation and 2.43±0.10 log c.f.u. /ml. for UHT milk
samples after four months of preservation. These result of the experiment suggests that both raw and
pasteurized milk tends to increased in microbial population during refrigeration on the other hand, UHT milk
which regards as a readily drinkable drink must not be purchased or consumed after three months from the
production due to the microbial content especially coliform bacteria in milk sample increased by substantial
amount.
Food processing, composition of milk, microorganism present, Different type of adulteration test (sugar, starch, Salt, urea), biochemical test (organoleptic, clot on boiling, alcohol, lactometer, fat determination, protein determination), different type of pasteurization, processing, spray drying, Standards of PFA, FSSAI, BIS (profile and regulations) & non food application of milk.
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
Study on physicochemical and microbial quality of available raw, pasteurized ...IJSIT Editor
Milk is a very popular drink in Bangladesh. This study was conducted to evaluate the microbial
content of milk during preservation and to make a suitable decision on the effect of preservation on the
microbial population in milk. Major tests considered in the research work were titratable acidity, COB test,
total viable bacteria count (TVC) and Coliform count. The initial average TVC in raw milk was 5.49±0.69 log
c.f.u. /ml. which increased to 6.25±0.10 log c.f.u. /ml. indicated deterioration in milk quality. In case of
pasteurized milk samples initial average total viable count was 4.43±0.17 log. c.f.u. /ml. increased to
5.92±0.05 log c.f.u. /ml. after six days of preservation. UHT milk samples which should not contain microbial
contamination also provided with initial average total viable count of 3.32±0.06 log c.f.u. /ml. and 3.59±0.04
log c.f.u. /ml. during preservation at room temperature for four months. Coliform bacteria usually cannot
survive at the pasteurization temperature .The initial average coliform bacteria were estimated 3.55±0.12 log
c.f.u. /ml. and 2.08±0.11 log c.f.u. /ml. for pasteurized and UHT milk samples which increase to 3.81±0.06 log.
c.f.u. /ml. for pasteurized milk after six days of preservation and 2.43±0.10 log c.f.u. /ml. for UHT milk
samples after four months of preservation. These result of the experiment suggests that both raw and
pasteurized milk tends to increased in microbial population during refrigeration on the other hand, UHT milk
which regards as a readily drinkable drink must not be purchased or consumed after three months from the
production due to the microbial content especially coliform bacteria in milk sample increased by substantial
amount.
Food processing, composition of milk, microorganism present, Different type of adulteration test (sugar, starch, Salt, urea), biochemical test (organoleptic, clot on boiling, alcohol, lactometer, fat determination, protein determination), different type of pasteurization, processing, spray drying, Standards of PFA, FSSAI, BIS (profile and regulations) & non food application of milk.
Crimson Publishers-Nutritional and Sensory Properties of Cashew Seed ( Anaca...CrimsonpublishersMCDA
Nutritional and Sensory Properties of Cashew Seed (Anacardium occidentale) Milk by Muhammad Faisal Manzoor in Modern Concepts & Developments in Agronomy
Effect of cooking temperature on some quality characteristic of Almond milkSkyfox Publishing Group
Processing of almond was done at different temperatures (80, 90, 100 and 110°C), to produce almond milk samples (A, B,
C and D). The almond milk sample (C) processed at normal boiling temperature (100°C) kept as reference standard. Using different
standard analytical methods, almond milk were analyzed for physiochemical, microbiological, and sensory attributes. Due to increase in
temperature the crude fat and moisture content decreased significantly (p<0.05)><0.05)><0.05) from 2.24-1.33×103 CFU/ml for sample A to D processed at 80-110°C, while yeast and mold from 1.22-0.35×102 CFU/ml.
The mean value score awarded to all sensory attributes increase from A to C but decrease in D. Almond milk products were acceptable,
highest acceptability score (8.33) awarded to milk sample C processed at 100°C followed by samples B, A and D. Processing of almond
milk at 100°C provide the better milk product with all measured characteristics suggested for almond milk processing.
Microbial Quality of Raw and Pasteurized Milk Samples Collected From Differen...iosrjce
Milk is the fluid normally secreted by female mammals for the nourishment of their young ones. It is
a compulsory part of daily diet for the expectant mothers as well as growing children and also serves as good
medium for microbial growth and contamination 240 raw milk samples and 72 pasteurized milk samples from
different places of Madurai District for a period of six months were analysed for microbial quality. Among the
raw milk samples only 19.1% of samples were good quality and 28.3% are very poor quality. In the pasteurized
milk samples 81.9% of samples were good for human consumption. The bacteria isolated from milk samples
includes Lactobacilli, Staphylococcus aureus, Escheritia coli, Bacillus subtilis , Salmonella typhi, and feacal
coliforms
Influence of variable water-soluble soy extract and inulin contents on the rh...IJERA Editor
The present study aimed to evaluate the influences of the partial substitution of caprine milk for water-soluble
soy extract (WSSE) and the addition of inulin on the rheological, technological and sensory properties of grapeflavored
yogurt-like beverages. For this purpose, a Central Composite Design (CCD) in conjunction with
Response Surface Methodology (RSM) was employed. WSSE and inulin influenced the overall acceptability of
the product, whereas syneresis, water holding capacity and rheological properties (the consistency index and the
flow behavior index) were influenced only by the WSSE content. RSM was shown to be an adequate statistical
tool that can be used for the development of formulations with specified properties in the range of the ingredient
concentrations studied.
Comparative Analysis of the proximate Composition of palmyrah pinattu and flo...Agriculture Journal IJOEAR
— Palmyrah (Borassusflabellifer) fruit is mostly used as fresh fruit, because of its perishable nature it is traditionally preserved as dried fruit pulp called as pinattu (fruit leather). It contained pectin as well as contain appreciable amount of saponinbecause of that fruit pulp having important medicinal properties. Considering these facts the phytochemical constituents of solvent extracts of pinattuwas identified and evaluated. Samples was collected from the three different branches ofPalmyrah Development Board.
Proximate and Microbial Profile of Couscous Yoghurt Produced from Soya MilkIJEAB
This study investigated the effect of milk type and mixture ratio on the proximate composition and microbial profile counts of couscous yoghurt. Yoghurts were first made from cow milk (CM), soya milk (SM) and equal mixture of both types of milk at ratio 50:50. Couscous was then mixed with yoghurts from cow milk (CMCY); soya milk (SMCY) and cow-soya milk (CSCY) at ratios of 90:10, 80:20 and 70:30 (yoghurt: couscous), w/w for the three respectively. The experiment was designed based on 2 factors (milk type and mixing ratio) at 3 levels, each resulting in a total of 9 treatments. Cow milk yoghurt without couscous was used as the control. Proximate compositions were determined using standard methods. Total viable microbial counts of samples were also determined. There were significant differences (p<0.05) in the proximate composition and CSCY at ratio 70:30 had the highest crude protein. In addition, CMCY at ratio 90:10 recorded the highest mean value for fat, while SMCY at ratio 80:20 and 70:30 recorded the least mean value for fat. All the couscous yoghurt samples had total viable cell counts of (<9 log CFU) that are within the acceptable range according to Codex Standards. In conclusion, the study has shown that CSCY at 70:30 had the highest nutrient content. Moreover, the products were also found to have low levels of microbial profile.
Inspection of the imported food products and internally produced food product...IOSRJAVS
This research had done on Export and Internal products which use by Afghan people. Tests on eggs showed that the internal eggs have better condition because of good weight, shell size, Albumin and yolk, and also there is no report of Salmonella. Tests on milk showed that the internal milk is good at high percentage of fat, Protein, Carbohydrates but there is always adulteration in these milks like adding water and starch. The research on water showed that there are hardness, No3, No2, P, some kinds of Bacteria but no Arsenic in tap, well and mineral water.In meat test we had found that, both import frozen meat and daily slaughter had the same condition of total bacteria and Coliforms but the percentage was normal, with no Salmonella. Results showed that import apple had high Bricks in refract meter than Herati apple.Tests of sausage and tuna products of our country and the external samples had no coliforms but high percentage of total bacteria.
Detection of the Antibacterial Activity of Bioactive Peptide Isolated from Fe...iosrjce
IOSR Journal of Pharmacy and Biological Sciences(IOSR-JPBS) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of Pharmacy and Biological Science. The journal welcomes publications of high quality papers on theoretical developments and practical applications in Pharmacy and Biological Science. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Plant-based milk alternative refers to non-dairy vegan milk made from breakdown of plant material like cereals, legumes oilseeds, nuts that are extracted in water and further homogenized to provide a creamy mouth feel along with flavor and aroma. It is a fast growing segment in the newer food product development category. Plant sources like almonds, soy, cashew, rice are utilized due to the nutritional properties of these sources for preparation of plant-based milk which is lactose-free, cholesterol free and low in calories. Dairy milk allergy, lactose intolerance, hormonal imbalance, calorie concern and more preference to vegan diets has influenced consumers towards choosing plant-based milk alternatives and it serves as an inexpensive and sustainable alternative to dairy milk. New and advanced non-thermal processing technologies are being developed for tackling the problems related to increase of shelf life, emulsion stability, nutritional completeness and sensory acceptability. Plant-based milk alternatives is a major research area in food science and technology and widely investigated through the development of advanced processing, technological interventions and fortification techniques for developing a nutritionally complete product with high overall acceptability.
ABSTRACT- The present study was undertaken to make paneer enriched with fiber otherwise fiber deficient paneer. Coconut powder is in the form of fiber was included in the preparation of paneer. Paneer is one such product which is a regular dietary favorite among the Indians. Paneer has short life span at room temperature. So, the present study was aimed to assess the shelf life of salted paneer at different intervals in refrigeration temperature and physico-chemical attributes also. Paneer is prepared by combined action of acid coagulants and heat treatment of buffalo and cow milk or a combination thereof. Paneer have pleasant odour and characteristic mild acidic flavour. No extraneous coloring matter should be added to paneer at any stage. Paneer is a highly perishable product and has limited shelf life, largely because of its high moisture content. Its shelf life was reported to be only six days under refrigeration, though its freshness is lost within three days. The spoilage of paneer occurs mainly due to the growth of microorganisms, which bring about various physico-chemical changes. The growth of microorganisms can be delayed and shelf life of paneer be increased by addition of salt in the paneer. All treatment combinations were analyzed for a total viable count (bacteria) on nutrient agar and fungi on PDA and Coliform on Mcconkey agar. All the samples had bacteriological count ranging from 1x104 to 14x104 cfu/gm. And in all samples coliform was absent, so the product was found to be good and proper hygienic condition were maintain during the preparation, handling, and storage.
Key words: Paneer, Standard Plate Count, Chemical analysis, Yeast and mould count, Fiber
Effect of Various Parameters on the Growth and Ethanol Production by Yeasts I...Shafkat Shamim Rahman
Two ethanol fermenting Saccharomyces cerevisiae were isolated from date juice and grapes and grown in YEPD medium. They were characterized for alcoholic fermentation using sugarcane molasses and their growth conditions were optimized with respect to pH and sugar concentration. Results revealed a temperature of 30ºC, pH 6.0 and 6.5% sugar concentration as optimum for fermentation. Stress tolerance tests showed that date juice isolate was highly tolerant to temperature, pH and high ethanol concentration in the medium. Under optimized conditions, S. cerevisiae isolated from date-juice produced 7.75% of ethanol in molasses as estimated by Conway method.
Crimson Publishers-Nutritional and Sensory Properties of Cashew Seed ( Anaca...CrimsonpublishersMCDA
Nutritional and Sensory Properties of Cashew Seed (Anacardium occidentale) Milk by Muhammad Faisal Manzoor in Modern Concepts & Developments in Agronomy
Effect of cooking temperature on some quality characteristic of Almond milkSkyfox Publishing Group
Processing of almond was done at different temperatures (80, 90, 100 and 110°C), to produce almond milk samples (A, B,
C and D). The almond milk sample (C) processed at normal boiling temperature (100°C) kept as reference standard. Using different
standard analytical methods, almond milk were analyzed for physiochemical, microbiological, and sensory attributes. Due to increase in
temperature the crude fat and moisture content decreased significantly (p<0.05)><0.05)><0.05) from 2.24-1.33×103 CFU/ml for sample A to D processed at 80-110°C, while yeast and mold from 1.22-0.35×102 CFU/ml.
The mean value score awarded to all sensory attributes increase from A to C but decrease in D. Almond milk products were acceptable,
highest acceptability score (8.33) awarded to milk sample C processed at 100°C followed by samples B, A and D. Processing of almond
milk at 100°C provide the better milk product with all measured characteristics suggested for almond milk processing.
Microbial Quality of Raw and Pasteurized Milk Samples Collected From Differen...iosrjce
Milk is the fluid normally secreted by female mammals for the nourishment of their young ones. It is
a compulsory part of daily diet for the expectant mothers as well as growing children and also serves as good
medium for microbial growth and contamination 240 raw milk samples and 72 pasteurized milk samples from
different places of Madurai District for a period of six months were analysed for microbial quality. Among the
raw milk samples only 19.1% of samples were good quality and 28.3% are very poor quality. In the pasteurized
milk samples 81.9% of samples were good for human consumption. The bacteria isolated from milk samples
includes Lactobacilli, Staphylococcus aureus, Escheritia coli, Bacillus subtilis , Salmonella typhi, and feacal
coliforms
Influence of variable water-soluble soy extract and inulin contents on the rh...IJERA Editor
The present study aimed to evaluate the influences of the partial substitution of caprine milk for water-soluble
soy extract (WSSE) and the addition of inulin on the rheological, technological and sensory properties of grapeflavored
yogurt-like beverages. For this purpose, a Central Composite Design (CCD) in conjunction with
Response Surface Methodology (RSM) was employed. WSSE and inulin influenced the overall acceptability of
the product, whereas syneresis, water holding capacity and rheological properties (the consistency index and the
flow behavior index) were influenced only by the WSSE content. RSM was shown to be an adequate statistical
tool that can be used for the development of formulations with specified properties in the range of the ingredient
concentrations studied.
Comparative Analysis of the proximate Composition of palmyrah pinattu and flo...Agriculture Journal IJOEAR
— Palmyrah (Borassusflabellifer) fruit is mostly used as fresh fruit, because of its perishable nature it is traditionally preserved as dried fruit pulp called as pinattu (fruit leather). It contained pectin as well as contain appreciable amount of saponinbecause of that fruit pulp having important medicinal properties. Considering these facts the phytochemical constituents of solvent extracts of pinattuwas identified and evaluated. Samples was collected from the three different branches ofPalmyrah Development Board.
Proximate and Microbial Profile of Couscous Yoghurt Produced from Soya MilkIJEAB
This study investigated the effect of milk type and mixture ratio on the proximate composition and microbial profile counts of couscous yoghurt. Yoghurts were first made from cow milk (CM), soya milk (SM) and equal mixture of both types of milk at ratio 50:50. Couscous was then mixed with yoghurts from cow milk (CMCY); soya milk (SMCY) and cow-soya milk (CSCY) at ratios of 90:10, 80:20 and 70:30 (yoghurt: couscous), w/w for the three respectively. The experiment was designed based on 2 factors (milk type and mixing ratio) at 3 levels, each resulting in a total of 9 treatments. Cow milk yoghurt without couscous was used as the control. Proximate compositions were determined using standard methods. Total viable microbial counts of samples were also determined. There were significant differences (p<0.05) in the proximate composition and CSCY at ratio 70:30 had the highest crude protein. In addition, CMCY at ratio 90:10 recorded the highest mean value for fat, while SMCY at ratio 80:20 and 70:30 recorded the least mean value for fat. All the couscous yoghurt samples had total viable cell counts of (<9 log CFU) that are within the acceptable range according to Codex Standards. In conclusion, the study has shown that CSCY at 70:30 had the highest nutrient content. Moreover, the products were also found to have low levels of microbial profile.
Inspection of the imported food products and internally produced food product...IOSRJAVS
This research had done on Export and Internal products which use by Afghan people. Tests on eggs showed that the internal eggs have better condition because of good weight, shell size, Albumin and yolk, and also there is no report of Salmonella. Tests on milk showed that the internal milk is good at high percentage of fat, Protein, Carbohydrates but there is always adulteration in these milks like adding water and starch. The research on water showed that there are hardness, No3, No2, P, some kinds of Bacteria but no Arsenic in tap, well and mineral water.In meat test we had found that, both import frozen meat and daily slaughter had the same condition of total bacteria and Coliforms but the percentage was normal, with no Salmonella. Results showed that import apple had high Bricks in refract meter than Herati apple.Tests of sausage and tuna products of our country and the external samples had no coliforms but high percentage of total bacteria.
Detection of the Antibacterial Activity of Bioactive Peptide Isolated from Fe...iosrjce
IOSR Journal of Pharmacy and Biological Sciences(IOSR-JPBS) is a double blind peer reviewed International Journal that provides rapid publication (within a month) of articles in all areas of Pharmacy and Biological Science. The journal welcomes publications of high quality papers on theoretical developments and practical applications in Pharmacy and Biological Science. Original research papers, state-of-the-art reviews, and high quality technical notes are invited for publications.
Plant-based milk alternative refers to non-dairy vegan milk made from breakdown of plant material like cereals, legumes oilseeds, nuts that are extracted in water and further homogenized to provide a creamy mouth feel along with flavor and aroma. It is a fast growing segment in the newer food product development category. Plant sources like almonds, soy, cashew, rice are utilized due to the nutritional properties of these sources for preparation of plant-based milk which is lactose-free, cholesterol free and low in calories. Dairy milk allergy, lactose intolerance, hormonal imbalance, calorie concern and more preference to vegan diets has influenced consumers towards choosing plant-based milk alternatives and it serves as an inexpensive and sustainable alternative to dairy milk. New and advanced non-thermal processing technologies are being developed for tackling the problems related to increase of shelf life, emulsion stability, nutritional completeness and sensory acceptability. Plant-based milk alternatives is a major research area in food science and technology and widely investigated through the development of advanced processing, technological interventions and fortification techniques for developing a nutritionally complete product with high overall acceptability.
ABSTRACT- The present study was undertaken to make paneer enriched with fiber otherwise fiber deficient paneer. Coconut powder is in the form of fiber was included in the preparation of paneer. Paneer is one such product which is a regular dietary favorite among the Indians. Paneer has short life span at room temperature. So, the present study was aimed to assess the shelf life of salted paneer at different intervals in refrigeration temperature and physico-chemical attributes also. Paneer is prepared by combined action of acid coagulants and heat treatment of buffalo and cow milk or a combination thereof. Paneer have pleasant odour and characteristic mild acidic flavour. No extraneous coloring matter should be added to paneer at any stage. Paneer is a highly perishable product and has limited shelf life, largely because of its high moisture content. Its shelf life was reported to be only six days under refrigeration, though its freshness is lost within three days. The spoilage of paneer occurs mainly due to the growth of microorganisms, which bring about various physico-chemical changes. The growth of microorganisms can be delayed and shelf life of paneer be increased by addition of salt in the paneer. All treatment combinations were analyzed for a total viable count (bacteria) on nutrient agar and fungi on PDA and Coliform on Mcconkey agar. All the samples had bacteriological count ranging from 1x104 to 14x104 cfu/gm. And in all samples coliform was absent, so the product was found to be good and proper hygienic condition were maintain during the preparation, handling, and storage.
Key words: Paneer, Standard Plate Count, Chemical analysis, Yeast and mould count, Fiber
Effect of Various Parameters on the Growth and Ethanol Production by Yeasts I...Shafkat Shamim Rahman
Two ethanol fermenting Saccharomyces cerevisiae were isolated from date juice and grapes and grown in YEPD medium. They were characterized for alcoholic fermentation using sugarcane molasses and their growth conditions were optimized with respect to pH and sugar concentration. Results revealed a temperature of 30ºC, pH 6.0 and 6.5% sugar concentration as optimum for fermentation. Stress tolerance tests showed that date juice isolate was highly tolerant to temperature, pH and high ethanol concentration in the medium. Under optimized conditions, S. cerevisiae isolated from date-juice produced 7.75% of ethanol in molasses as estimated by Conway method.
Similar to Chemical and Microbiological Quality Assessment of Raw and Processed Liquid Market Milks of Bangladesh (20)
Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic ...Sérgio Sacani
We characterize the earliest galaxy population in the JADES Origins Field (JOF), the deepest
imaging field observed with JWST. We make use of the ancillary Hubble optical images (5 filters
spanning 0.4−0.9µm) and novel JWST images with 14 filters spanning 0.8−5µm, including 7 mediumband filters, and reaching total exposure times of up to 46 hours per filter. We combine all our data
at > 2.3µm to construct an ultradeep image, reaching as deep as ≈ 31.4 AB mag in the stack and
30.3-31.0 AB mag (5σ, r = 0.1” circular aperture) in individual filters. We measure photometric
redshifts and use robust selection criteria to identify a sample of eight galaxy candidates at redshifts
z = 11.5 − 15. These objects show compact half-light radii of R1/2 ∼ 50 − 200pc, stellar masses of
M⋆ ∼ 107−108M⊙, and star-formation rates of SFR ∼ 0.1−1 M⊙ yr−1
. Our search finds no candidates
at 15 < z < 20, placing upper limits at these redshifts. We develop a forward modeling approach to
infer the properties of the evolving luminosity function without binning in redshift or luminosity that
marginalizes over the photometric redshift uncertainty of our candidate galaxies and incorporates the
impact of non-detections. We find a z = 12 luminosity function in good agreement with prior results,
and that the luminosity function normalization and UV luminosity density decline by a factor of ∼ 2.5
from z = 12 to z = 14. We discuss the possible implications of our results in the context of theoretical
models for evolution of the dark matter halo mass function.
Slide 1: Title Slide
Extrachromosomal Inheritance
Slide 2: Introduction to Extrachromosomal Inheritance
Definition: Extrachromosomal inheritance refers to the transmission of genetic material that is not found within the nucleus.
Key Components: Involves genes located in mitochondria, chloroplasts, and plasmids.
Slide 3: Mitochondrial Inheritance
Mitochondria: Organelles responsible for energy production.
Mitochondrial DNA (mtDNA): Circular DNA molecule found in mitochondria.
Inheritance Pattern: Maternally inherited, meaning it is passed from mothers to all their offspring.
Diseases: Examples include Leber’s hereditary optic neuropathy (LHON) and mitochondrial myopathy.
Slide 4: Chloroplast Inheritance
Chloroplasts: Organelles responsible for photosynthesis in plants.
Chloroplast DNA (cpDNA): Circular DNA molecule found in chloroplasts.
Inheritance Pattern: Often maternally inherited in most plants, but can vary in some species.
Examples: Variegation in plants, where leaf color patterns are determined by chloroplast DNA.
Slide 5: Plasmid Inheritance
Plasmids: Small, circular DNA molecules found in bacteria and some eukaryotes.
Features: Can carry antibiotic resistance genes and can be transferred between cells through processes like conjugation.
Significance: Important in biotechnology for gene cloning and genetic engineering.
Slide 6: Mechanisms of Extrachromosomal Inheritance
Non-Mendelian Patterns: Do not follow Mendel’s laws of inheritance.
Cytoplasmic Segregation: During cell division, organelles like mitochondria and chloroplasts are randomly distributed to daughter cells.
Heteroplasmy: Presence of more than one type of organellar genome within a cell, leading to variation in expression.
Slide 7: Examples of Extrachromosomal Inheritance
Four O’clock Plant (Mirabilis jalapa): Shows variegated leaves due to different cpDNA in leaf cells.
Petite Mutants in Yeast: Result from mutations in mitochondrial DNA affecting respiration.
Slide 8: Importance of Extrachromosomal Inheritance
Evolution: Provides insight into the evolution of eukaryotic cells.
Medicine: Understanding mitochondrial inheritance helps in diagnosing and treating mitochondrial diseases.
Agriculture: Chloroplast inheritance can be used in plant breeding and genetic modification.
Slide 9: Recent Research and Advances
Gene Editing: Techniques like CRISPR-Cas9 are being used to edit mitochondrial and chloroplast DNA.
Therapies: Development of mitochondrial replacement therapy (MRT) for preventing mitochondrial diseases.
Slide 10: Conclusion
Summary: Extrachromosomal inheritance involves the transmission of genetic material outside the nucleus and plays a crucial role in genetics, medicine, and biotechnology.
Future Directions: Continued research and technological advancements hold promise for new treatments and applications.
Slide 11: Questions and Discussion
Invite Audience: Open the floor for any questions or further discussion on the topic.
Introduction:
RNA interference (RNAi) or Post-Transcriptional Gene Silencing (PTGS) is an important biological process for modulating eukaryotic gene expression.
It is highly conserved process of posttranscriptional gene silencing by which double stranded RNA (dsRNA) causes sequence-specific degradation of mRNA sequences.
dsRNA-induced gene silencing (RNAi) is reported in a wide range of eukaryotes ranging from worms, insects, mammals and plants.
This process mediates resistance to both endogenous parasitic and exogenous pathogenic nucleic acids, and regulates the expression of protein-coding genes.
What are small ncRNAs?
micro RNA (miRNA)
short interfering RNA (siRNA)
Properties of small non-coding RNA:
Involved in silencing mRNA transcripts.
Called “small” because they are usually only about 21-24 nucleotides long.
Synthesized by first cutting up longer precursor sequences (like the 61nt one that Lee discovered).
Silence an mRNA by base pairing with some sequence on the mRNA.
Discovery of siRNA?
The first small RNA:
In 1993 Rosalind Lee (Victor Ambros lab) was studying a non- coding gene in C. elegans, lin-4, that was involved in silencing of another gene, lin-14, at the appropriate time in the
development of the worm C. elegans.
Two small transcripts of lin-4 (22nt and 61nt) were found to be complementary to a sequence in the 3' UTR of lin-14.
Because lin-4 encoded no protein, she deduced that it must be these transcripts that are causing the silencing by RNA-RNA interactions.
Types of RNAi ( non coding RNA)
MiRNA
Length (23-25 nt)
Trans acting
Binds with target MRNA in mismatch
Translation inhibition
Si RNA
Length 21 nt.
Cis acting
Bind with target Mrna in perfect complementary sequence
Piwi-RNA
Length ; 25 to 36 nt.
Expressed in Germ Cells
Regulates trnasposomes activity
MECHANISM OF RNAI:
First the double-stranded RNA teams up with a protein complex named Dicer, which cuts the long RNA into short pieces.
Then another protein complex called RISC (RNA-induced silencing complex) discards one of the two RNA strands.
The RISC-docked, single-stranded RNA then pairs with the homologous mRNA and destroys it.
THE RISC COMPLEX:
RISC is large(>500kD) RNA multi- protein Binding complex which triggers MRNA degradation in response to MRNA
Unwinding of double stranded Si RNA by ATP independent Helicase
Active component of RISC is Ago proteins( ENDONUCLEASE) which cleave target MRNA.
DICER: endonuclease (RNase Family III)
Argonaute: Central Component of the RNA-Induced Silencing Complex (RISC)
One strand of the dsRNA produced by Dicer is retained in the RISC complex in association with Argonaute
ARGONAUTE PROTEIN :
1.PAZ(PIWI/Argonaute/ Zwille)- Recognition of target MRNA
2.PIWI (p-element induced wimpy Testis)- breaks Phosphodiester bond of mRNA.)RNAse H activity.
MiRNA:
The Double-stranded RNAs are naturally produced in eukaryotic cells during development, and they have a key role in regulating gene expression .
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T J Hossain et al.,: Continental J. Food Science and Technology 5 (2): 6 - 17, 2011
because there is great danger in the latter case of the germs of infectious and contagious diseases being
introduced into the milk, and so disseminated (Ghosh and Maharjan 2002; Barthel 1910).
The Bangladesh Standards and Testing Institution (BSTI) obliges various chemical and sanitary requirements
for the pasteurized milk (BSTI 2002). However, no standard is known to be established for the raw and UHT-
treated milk.
So far, no work had been reported on the quality evaluation of liquid market milks of Bangladesh. The
objectives of this study were to determine the bacterial load, nutritive value and degree of cleanliness
surrounding the production and handling of the milk samples as well as to find out the differences among the
raw, pasteurized and UHT-processed milks in terms of chemical composition and bacterial distribution.
MATERIALS AND METHODS
Collection of samples
In Bangladesh, milk is generally sold in two ways. In most cases, the farmers bring milk in open pots and sell it
directly in the market without any processing and packaging. In other cases, milk companies collect milk from
the farmers or dairy farms, process it via pasteurization or UHT treatment and package the processed milk
which is then sold in shops under specific brand name. In this study, raw milks were purchased from a local
daily market while brand milks were bought from different shops. The samples were chosen at random. A total
of twelve samples were examined. Six (designated as R-1, R-2, R-3, R-4, R-5, and R-6) were raw milk bought
from different vendors. Of the remaining six, three (P-7, P-8, P-9) were pasteurized milks each from different
brand and the other three (U-10, U-11, U-12) were UHT-processed also from different brands. All the samples
were collected in the sellers’ usual form (plastic packets), instantly transported to the laboratory maintaining
cold state and examined immediately.
Chemical analysis
Percentage of water was determined by subtracting the value of total soluble solids (TSS) from 100.
TSS was determined by using refractometer (portable refractometer, model: FG 103, Brix 0-32%; Comecta S.
A.) (Daniel 2010).
Milk fat was measured by Rose-Gottlieb's method (Barthel 1910).
Amount of solids-non-fat (SNF) was determined by subtracting the amount of fat from TSS.
Lactose was determined by volumetric method (Heineman 1919). 20 ml of milk was diluted with water to a
volume of 400 ml and 8-16 drops of a 10% solution of acetic acid added. The precipitate was filtered off and
washed with cold water (4°C). The filtrate was boiled in a flask and the albumin precipitated. This was filtered
off also and the precipitate was washed with cold water (4°C). The filtrates and wash water (water obtained
upon washing the precipitate with cold water) were mixed and measured accurately. A portion of this mixture
was placed in a burette, and this was run into a boiling mixture of 20 ml Fehling's solution and 80 ml water.
After the copper had been completely precipitated, the number of ml used was read. 20 ml Fehling's solution
corresponds to 0.135 gram milk-sugar.
Protein was measured by Kjeldahl method (Crampton and Harris 1969; Jacobs 1973; Mitchell 1972; Pearson
1977).
Ash content was determined by the method described by Maynard (1970).
Acidity was measured by titration with 0.1 N sodium hydroxide solution and using 1% ethanol solution of
phenolphthalein as indicator (Lampert 1947).
Water content of milk is usually 87.25% (Eckles et al 1951) and it ranges from 84.0 to 89.0% (Lampert, 1947).
In this paper, samples with water content of more than 90% were regarded as adulterated with water.
Presence of the other adulterants was tested by specific qualitative tests (www.dairyforall.com):
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T J Hossain et al.,: Continental J. Food Science and Technology 5 (2): 6 - 17, 2011
Neutralizers: 20 ml of milk was taken in a silica crucible, the water was evaporated and the contents were burnt
in a muffle furnace. The ash was dispersed in 10 ml distilled water and it was titrated against decinormal (N/10)
hydrochloric acid using phenolphthalein as an indicator. If the titre value exceeded 1.2 ml, then it was construed
that the milk was adulterated with neutralizers.
Formalin: 10 ml of milk was taken in test tube and 5 ml of conc. sulphuric acid was added on the sides of the
test tube without shaking. Appearance of a violet or blue ring at the intersection of the two layers indicated the
presence of formalin.
Sucrose: 10 ml of milk was taken in a test tube and 5 ml of hydrochloric acid was added along with 0.1 g of
resorcinol. Then the test tube was shaken well and placed in a boiling water bath for 5 min. Appearance of red
colour indicated the presence of added sugar in milk.
Starch: 3 ml milk was taken in a test tube and boiled thoroughly. Then milk was cooled to room temperature and
added with 2 to 3 drops of 1% iodine solution. Change of colour to blue indicated that the milk was adulterated
with starch.
Glucose: 3 ml of milk was taken in a test tube and 3 ml Barford’s reagent was added and mixed thoroughly.
Then it was kept in a boiling water bath for 3 min and then cooled for 2 min by immersing in tap water without
disturbance. Then 1 ml of phosphomolybdic acid was added and shaken. If blue colour was visible, then glucose
was present in the milk sample.
Salt: 5 ml of silver nitrate (0.8%) was taken in a test tube and added with 2 to 3 drops of 1% potassium
dichromate and 1 ml of milk and thoroughly mixed. If the contents of the test tube turned yellow in colour, then
milk contained salt in it. If it was chocolate coloured, then the milk was free from salt.
Bacteriological analysis
Standard Plate Count (SPC) method recommended for dairy products (APHA 1960) was followed for
quantitative analysis of bacteria:
Enumeration of total viable bacteria: Nutrient agar medium (Difco) was used for enumeration of total viable
bacteria. pH of the medium was adjusted at 6.8 prior to sterilization. Inoculated plates were incubated at 37°C
for 24 to 72 hours to facilitate viable bacterial growth. After incubation, the inoculated plates having 30 to 300
colonies were considered for counting using colony counter (Gallenkamp, England) and following back
calculation total count was expressed as colony forming units per milliliter (cfu/ml).
Enumeration of total coliform bacteria: Total coliform was determined by the same method used in the
enumeration of total viable bacteria. The medium used for coliform was MacConkey agar. Inoculated plates
were incubated at 37°C for 24 hours. After incubation, typical pinkish and centrally red colonies were counted
by using colony counter and total coliform was calculated.
Enumeration of total fecal coliform bacteria: Fecal coliform (mFc) agar medium was used for the enumeration
of fecal coliform. The media were inoculated and after incubation at 44°C for 24 hours, typical bluish colonies
were counted using colony counter and using back calculation, total fecal coliform count determined.
Enumeration of total Staphylococcus bacteria: Staphylococcus medium was used for the enumeration of
Staphylococcus bacteria. Media were inoculated and after incubation at 37°C for 24 hours, colonies were
counted using colony counter and following back calculation, total Staphylococcus count was obtained in
cfu/ml.
Enumeration of total Salmonella and Shigella: Salmonella and Shigella agar (SSA) medium was used for
enumeration of Salmonella and Shigella. Media were inoculated and after incubation at 37°C for 24 hours
colonies were counted using colony counter and following back calculation, the total Salmonella and Shigella
count was obtained.
Enumeration of Total Aeromonas hydrophila: Starch ampicillin agar medium was used for the enumeration of
total viable Aeromonas bacteria. Agar plate media were inoculated and after incubation at 37°C for 24 hours,
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T J Hossain et al.,: Continental J. Food Science and Technology 5 (2): 6 - 17, 2011
typical pinkish honey colonies were counted using colony counter and following back calculation, total
aeromonas count was determined.
Enumeration of Total Psychrophilic Bacteria: Nutrient agar medium was also used to enumerate total
psychrophilic bacteria. Inoculated plates were incubated at 4°C for 15 days to facilitate the growth of
psychrophilic bacteria. After incubation, colonies were counted using colony counter and following back
calculation, total psychrophilic bacterial count was determined.
For obtaining single colony isolate, the method described by Sharp and Lyles (1969) was used. Morphologically
dissimilar well-spaced colonies were picked up with the help of a sterile loop from the plates, which had from
30 to 300 colonies. Each colony was streaked on to freshly prepared plates of the same media and incubated at
37°C for 24 hours or more. After incubation, typical pure colonies were taken as isolates.
The selected isolates were then purified through repeated streak plating. When plating produced only one type
of colony in a particular plate, it was considered to be pure. The purified isolates were then transferred to
nutrient agar slant in one drum screw capped culture vial and preserved as stock culture.
Identification was done up to genus by following the ‘Bergey’s manual of determinative bacteriology,’
(Buchanan and Gibbons 1974). For identification, different morphological characteristics including shape, size,
form, texture, opacity, edge, elevation of the isolated colonies were studied carefully and after Gram staining,
microscopic examination was carried out. The biochemical tests performed were catalase test, oxidase test,
methyl-red test (MR Test), Voges-proskauer test (VP Test), production of hydrogen sulphide (KIA Test),
hydrolysis of starch and fermentation tests.
RESULTS AND DISCUSSION
Chemical composition
The percentage of water, total soluble solids (TSS), fat, solids-non-fat (SNF), lactose, protein, and ash has been
presented in Table 1.
Five (R-2 to R-6) of the six raw milks contained more than 90% water which is above the usual range i.e. 84.0
to 89.0% (Eckles et al 1951), suggesting that they were adulterated with water. Among the heat-treated milk,
only P-7 contained high percentage of water i.e. 90.83% (Table 1).
Addition of water dilutes milk reducing its TSS content. Reduced TSS was observed in five raw (R-2 to R-6)
and one pasteurized (P-7) milk; none of these samples had TSS over 9.5% though milk TSS usually ranges from
10.5 to 14.5% (O'Mahony 1988). The UHT-milks were comparatively rich in TSS content each having at least
11.0% TSS (Table 1).
Commercially, the fat of milk is unquestionably the most valuable constituent of milk. Milk having a fair
amount of fat is more valuable as a food than milk which is poor in fat. The Food and Drug Administration
(FDA) requires not less than 3.25% milk fat for fluid whole milk. The U.S. public health service (USPHS) Milk
Ordinance and Code also recommended a minimum of 3.25% butterfat in farm milk (Graf 1976). However, in
this study, three of the raw milks (R-2, R -3, and R-6) contained less than 3.25% fat. The other three (R-1, R -4,
and R-5), however, satisfied the criterion each having at least 3.3% fat. The BSTI (2002) requirement for fat
content of pasteurized milk is a minimum of 3.5% which is fulfilled by only one (P-9) of the three pasteurized
milks. The other two (P-7 & P -8) had fat contents of 3.34% and 3.4% respectively. The fat content of U-12, one
of the UHT-processed milks, was even less (3.09%). Data have been presented in Table 1.
FDA standard for SNF content of whole milk is a minimum of 8.25% (Graf 1976). None of the raw milks
maintained this standard. Five of these even contained SNF of less than 6.5% indicating that these might have
been adulterated with water. The pasteurized milks also failed to maintain the minimum SNF requirement set by
BSTI (2002) which is 8.0%. Two (P-8 and P-9) of these had SNF values of more than 7%, whereas SNF of the
other (P-7) was exceptionally low, 5.83%. In case of the UHT processed milk, two (U-11& U-12) had SNF
contents of more than 8.0% whereas SNF of the other (U-10) was near to 8.0% (Table 1).
The percentage of lactose of most of the raw milks was around 4.25%, similar to that reported by Lingathurai et
al (2009). The lactose content of milk though can range from 3.6 to 5.5% (O'Mahony 1988). The specifications
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T J Hossain et al.,: Continental J. Food Science and Technology 5 (2): 6 - 17, 2011
for pasteurized milk, established by BSTI (2002), require at least 4.4% lactose in milk. All the three pasteurized
milks fulfilled the requirement. The lactose content of the UHT-milks was even higher, around 4.9%, the
highest being 4.97% obtained in U-10 (Table 1).
Table 1: Chemical composition of the samples.
Sample
% of constituents
Water TSS Fat SNF Lactose Protein Ash
R-1
89.0 11.0 3.75 7.25 4.83 3.57 0.80
R-2
91.0 9.0 3.15 5.85 4.30 3.16 0. 70
R-3
91.0 9.0 3.18 5.82 4.14 3.07 0. 74
R-4
90.50 9.50 3.41 6.09 4.21 3.20 0. 72
R-5
90.73 9.27 3.30 5.97 4.53 3.26 0.74
R-6
90.77 9.23 3.12 6.11 4.10 3.30 0.69
BSTI Std. for
Pasteurized milk
-- -- 3.50 8.0 4.4 3.3 0.70
P-7
90.83 9.17 3.34 5.83 4.65 3.35 0.64
P-8
89.0 11.0 3.40 7.60 4.82 3.49 0.67
P-9
89.17 10.83 3.72 7.11 4.78 3.51 0.71
U-10
88.0 12.0 3.62 8.38 4.97 3.68 0.75
U-11
88.0 12.0 3.44 8.56 4.80 3.52 0.75
U-12
89.0 11.0 3.09 7.91 4.88 3.43 0.69
R = Raw milk, P = Pasteurized milk, U = UHT-treated milk, BSTI = Bangladesh Standards and Testing
Institution, TSS = Total Soluble Solids, SNF = Solids-Non-Fat
The protein content of the raw milks varied from 3.07% to 3.57%. Lingathurai et al (2009) reported slightly
higher (3.77%) protein content. The three pasteurized milks were of acceptable quality with respect to protein
content according to BSTI (2002) norms (not lower than 3.3%). All the pasteurized milks satisfied this
requirement each containing a minimum of 3.35% protein. The UHT-milks were also of good quality regarding
protein content each having at least 3.4% of protein (Table 1).
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It was interesting to find that the raw milks, though inferior in fat, sugar and protein contents in most cases, had
minerals greater than the pasteurized milks. The ash content of the raw milks varied from 0.69% to 0.8% which
falls within the usual range of 0.6 to 0.9% (O'Mahony 1988). But It is higher than that (0.33- 0.69%) found by
Elmagli and El Zubeir (2006). Ash content of the pasteurized milks ranged from 0.64% to 0.71%, whereas BSTI
(2002) demands at least 0.7% of ash for the pasteurized milk. On the other hand, two of the UHT-milks (U-11 &
U-12) were quite rich in the mineral content, each containing 0.75% of ash (Table 1).
Acidity
Table 2 depicts the titratable acidity of the samples.
Table 2: Titratable acidity of the samples.
Sample
Titratable Acidity
(% lactic acid)
R-1 0.216
R-2 0.180
R-3 0.200
R-4 0.171
R-5 0.135
R-6 0.162
BSTI Std. for
pasteurized milk
Max 0.150
P-7 0.144
P-8 0.162
P-9 0.162
U-10 0.189
U-11 0.144
U-12 0.175
Titratable acidity is a measure of freshness and bacterial activity in milk. Popescu and Angel (2009) reported
that high quality milk has to have less than 0.14 percent acidity. The acidity of the raw milk samples varied
largely from one sample to another. The highest value was 0.216 % (R-1) indicating high bacterial activity and
the lowest was 0.135% (R-5) indicating it’s relatively better quality with regards to freshness. The acidity of the
pasteurized milks ranged from 0.144% to 0.162%, where BSTI (2002) allows a max. acidity of 0.15% for the
pasteurized milks. Elmagli and El Zubeir (2006) observed a greater range of acidity (0.14 to 0.86%) in
pasteurized milks. No bacteria were found in the UHT-milks U-10 and U-12, but both these showed high degree
of titratable acidity (0.189% and 0.175% respectively) suggesting that the high acidity might have developed
prior to the heat treatment (Table 2).
Titratable acidity of milk has long been recognized and employed as an indicator of quality (Jaynes et al 1980).
It is expressed in terms of percentage lactic acid since lactic acid is the principal acid produced by fermentation
after milk is drawn from the udder. Fresh milk, however, does not contain any appreciable amount of lactic acid
and therefore an increase in acidity is a rough measure of its age and bacterial activity (O'Mahony 1988;
Lampart 1947). Within a short time after milking, the acidity increases perceptibly due to bacterial activity. The
degree of bacterial contamination and the temperature at which the milk is kept are the chief factors influencing
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T J Hossain et al.,: Continental J. Food Science and Technology 5 (2): 6 - 17, 2011
acid formation. Therefore, the amount of acid depends on the cleanliness of production and the temperature at
which milk is kept. For this reason, determination of acid in milk is an important factor in judging milk quality.
Acidity affects taste as well. When it reaches about 0.3%, the sour taste of milk becomes sensible. At 0.4%
acidity, milk is clearly sour, and at 0.6% it precipitates at normal temperature. At acidity over 0.9%, it
moulds ((Heineman 1919; Tzouwara-Karayanni 2000).
Adulteration
Results for the presence of adulterants are given in Table 3.
Table 3: Presence of adulterants.
Sample
Added
water
Neutralizer Formalin Sucrose Starch Glucose Salt
R-1 - - - - - - -
R-2 + - - - - - -
R-3 + - - - - - -
R-4 + - - - - - -
R-5 + - - - - - -
R-6 + - - - - - -
P-7 + - - + - - -
P-8 - - - + - - -
P-9 - - - - - - -
U-10 - - - + - - -
U-11 - - - + - - -
U-12 - - - + - - -
‘+’ = Present, ‘-’ = Absent
No neutralizer, preservative, added sugar, glucose, starch, or salt was found in raw milks. Five (R-2, R-3, R-4,
R-5, and R-6) of the raw milks, however, had been adulterated with water which is very common in Bangladesh
particularly in case of raw milk. Addition of water dilutes the amount of total solids in milk and it also involves
the danger of introducing germs into milk including the pathogens. Adulteration of milk with water therefore
may introduce chemical or microbial hazards to health. It reduces nutritional and processing quality, palatability
as well as marketing value of milk (Swai and Schoonman 2011).Water had also been added in one (P-7) of the
pasteurized milks. The other adulterant detected was added sugar (sucrose) which was found in five (P-7, P-8,
U-10, U-11, and U-12) of the six processed milks (Table 3).
Bacterial distribution
The results of bacterial distribution in the samples are presented in Table 4.
All the raw milks had high bacterial load which ranged from 1.75×106
to 1.22×108
cfu/ml. The most frequent
cause of high bacterial load is poor cleaning of the milking system. Bacterial count was high due to milking
dirty udders, maintaining an unclean milking and housing environment, and failing to rapidly cool milk to less
than 40°F. The TVBC (total viable bacterial count) of the pasteurized milk samples ranged from 7.5×107
to
1.24×108
cfu/ml, much higher than that recommended by BSTI and USPHS (not exceeding 20,000 cfu/ml)
(BSTI 2002; Jay 2003). The reason for high bacterial count in the pasteurized milks may include defective
pasteurization machinery, surviving pasteurization, and post-pasteurized contamination due to poor processing
and handling conditions and/or poor hygienic practices by workers. However, TVBC of each of the UHT-
processed milks was nil, indicating their excellent sanitary quality (Table 4).
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T J Hossain et al.,: Continental J. Food Science and Technology 5 (2): 6 - 17, 2011
Coliforms are considered as ‘indicator organisms’ because their presence in food indicates some form of
contamination. Coliform count in the raw milks ranged from 4.5×103
to 2.03×106
cfu/ml. These results are
higher than that obtained by Saitanu et al (1996), who found TCC (total coliform count) of <1000 cfu/ml.
However, TCC obtained in the study of Sraïri et al (2006) varied from less than 30 to 2.08 × 107
cfu/ml in raw
milk. Poor herd hygiene, contaminated water, unsanitary milking practices, and improperly washed and
maintained equipment can all lead to higher coliform counts in raw milk (CDFA 2008). Pasteurized milk P-8
didn’t contain any coliform, whereas TCC of the other two pasteurized milks were 3.7×104
and 1.2×106
cfu/ml
though the standard has been set by BSTI (2002) at less than 10 colonies/ml. USPHS allows not over 10
colonies for ‘Grade A’ pasteurized milk (Jay 2003). Coliforms do not survive pasteurization (CDFA 2008). So
their presence in the pasteurized milks indicates recontamination after pasteurization. The UHT-milks were
completely free from any coliform (Table 4).
Table 4: Distribution of bacteria (cfu/ml)
Sample
TVBC
(cfu/ml)
TCC
(cfu/ml)
TFCC
(cfu/ml)
TSC
(cfu/ml)
TSSC
(cfu/ml)
TAHC
(cfu/ml)
TPBC
(cfu/ml)
R-1
1.22×108
1.36×106
3.3×105
2.84×105
1.4×105
1.63×107
2×105
R-2
3.3×107
5×105
9.5×104
1.45×105
2.9×105
6×104
9.2×104
R-3
1.75×106
4.5×103
3.8×103
1.2×105
Nil Nil 1.6×104
R-4
2.9×107
5.4×105
1×105
1.48×106
Nil Nil 1.98×104
R-5
6.1×107
3.6×105
Nil 1.54×105
Nil Nil 1.02×105
R-6
2.4×107
2.03×106
4.8×105
5.7×104
5.9×105
4.4×105
2.08×104
BSTI Std. for
pasteurized milk
Maximum
2×104
Less than
10
-- -- -- -- --
P-7
7.5×107
3.7×104
5.5×103
1.4×103
6.1×104
Nil 4.9×103
P-8
8.3×107
Nil Nil 1.6×103
Nil Nil 4×102
P-9
1.24×108
1.2×106
1×104
8.1×104
1.2×106
Nil 1.87×104
U-10
Nil Nil Nil Nil Nil Nil Nil
U-11
Nil Nil Nil Nil Nil Nil Nil
U-12
Nil Nil Nil Nil Nil Nil Nil
cfu/ml = colony forming units per milliliter, TVBC = Total viable bacterial count, TCC = Total coliform count, TFCC
= Total fecal coliform count, TSC =Total staphylococcal count, TAHC = Total Aeromonas hydrophila count, TSSC =
Total Salmonella and Shigella count, TPBC = Total psychrophilic bacterial count
Among the raw and pasteurized milks, two samples, R-5 and P-8, didn’t have any fecal coliform but others
showed quite high count, higher than that found by Sraïri et al (2006) in the raw milk of some dairy farms in
Morocco. The fecal coliforms are more closely related to fecal contamination than are the total coliforms. The
organisms can originate from improperly sanitized working surfaces in a processing plant. In these cases, their
presence would reflect the quality of sanitation and not the direct pollution of the product (Banwart 2004). The
UHT-milks didn’t contain any fecal coliform (Table 4).
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T J Hossain et al.,: Continental J. Food Science and Technology 5 (2): 6 - 17, 2011
A large percentage of all cases reported as food poisoning or food infection is actually Staphylococcus
poisoning and many people encounter this illness during their lifetime. The staphylococcal food intoxication
accounted for over 17% of all the outbreaks and almost 34% of the cases of reported foodborne illnesses in the
United States in 1981 (Frazier and Westhoff 2005; Banwart 2004). In this study, Staphylococcus was found in
all of the raw and pasteurized milks but not found in the UHT-milk. TSC (total staphylococcal count) in the raw
milks ranged from 5.7×104
to 1.48×106
cfu/ml. These counts are less than the findings of Khan and Abdul
(2002) where the mean staphylococcal counts were 4.7×106
cfu/ml in raw milk, but higher than that of Sraïri et
al (2006) where TSC ranged from less than 30 cfu/ml to 10820 cfu/ml. In the pasteurized milks TSC ranged
from 1.4×103
to 8.1×104
cfu/ml (Table 4).
The UHT-milks, three raw milks (R-3, R-4, and R-5) and one pasteurized milk (P-8) didn’t show TSSC (total
salmonella and shigella count). However, in the remaining three raw milks TSSC varied from 1.4×105
to
5.9×105
cfu/ml. P-7 and P-9 also showed high TSSC (Table 4). The salmonellae are said to be ubiquitous, being
worldwide and found in or on soil, water, sewage, animals, humans, processing equipment, feed, and various
food products (Banwart 2004). Khan and Abdul (2002) though did not obtain any Salmonella or Shigella in raw
milks in their study on ‘Microbiological quality of milk, vegetables and fruit juices’. Members of Salmonella are
potentially pathogenic for humans. The transmission of the disease is usually from animals to humans by
ingestion of food of animal origin. Raw milk has been the vehicle for salmonellae causing salmonellosis
throughout the world, whereas a widespread outbreak in 1985, affecting over 16,000 people in several states,
involved pasteurized milk. This incident should make us aware that pasteurization systems and proper
procedures for handling pasteurized milk are needed to prevent salmonellosis and perhaps other illnesses
(Banwart, 2004).
Three of the six raw milks (R-1, R-2, and R-6) contained A. hydrophila with the total count ranging from 6×104
to 1.63×107
cfu/ml (Table 4). The Aeromonas spp. are often introduced from water which is thought to be the
main source of contamination (Bizani and Brandelli 2001). The isolation of Aeromonas from raw milk has been
reported by Khalil (1997). Nahla (2006) also reported the presence of Aeromonas in raw and pasteurized milks.
In this study, however, the pasteurized and UHT-processed milks didn’t contain any A. hydrophila. Fourteen
species of Aeromonas have been described, five of which, including A. hydrophila, are currently recognized as
human pathogens (Janda and Abbott 1998).
TPBC (total psychrophilic bacterial count) of raw milks varied from 1.6×104
to 2×105
cfu/ml and that of the
pasteurized milks ranged from 4×102
to 1.87×104
cfu/ml. The UHT-milks didn’t possess any psychrophiles as
usual (Table 4). Presence of psychrotrophs in the pasteurized milks indicates post-pasteurization contamination.
Psychrotrophs are becoming increasingly dangerous to the dairy industry because they produce extracellular
heat- resistant lipases and proteases. Milk altered by the activity of these enzymatic systems is depreciated and
must be eliminated from processing. TPBC is used as a supplementary indicator of milk quality. Data on TPBC
are required by some dairies because of specific technological requirements and quality-dependent payment for
raw milk supplies. The current EU standards for top quality milk require that TPBC shall not exceed 5,000
CFU/ml. (Cempírková 2002).
A major reason of the poor bacterial quality of the raw milks is adulteration with addition of water. Water is
added to milk to increase its volume. Addition of water reduces the percentages of the soluble solids including
fat and the other vital components in milk and at the same time it involves the danger of introducing germs that
may even be pathogenic. Diluting milk with pure water, however, may lead only to malnutrition; but adding
impure water may cause intestinal problems (KDB Training guide 2004, Kurwijila 2006).
CONCLUSIONS
The UHT-treated milks were much better than the raw and pasteurized milks particularly from sanitary point of
view and two of these, U-10 and U-11, were the bests of all samples considering most parameters. The hygienic
standard of the raw and pasteurized milks was very poor. All the raw and pasteurized milks had high bacterial
loads and some contained pathogenic bacteria. The UHT milks didn’t contain any. Few of the raw and
pasteurized milks were also inferior in fat content. Two adulterants, added water and sucrose, were identified in
a number of raw and pasteurized milks. The presence of the pathogenic organisms, the high counts of coliforms
and the high levels of adulteration are indicative of a potentially hazardous product which is likely to be
posing a serious health risk to the consumers. The government therefore should conduct frequent inspection of
the marketed milks to check whether they meet the minimum legal standards and should monitor the overall
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T J Hossain et al.,: Continental J. Food Science and Technology 5 (2): 6 - 17, 2011
hygienic condition surrounding the production and handling of milk. Realistic standards for the raw milks need
to be devised and appropriate training should be given to the raw milk producers in hygienic handling of milk.
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www.dairyforall.com www.dairyforall.com/milk-adulteration.php
Received for Publication: 23/06/2011
Accepted for Publication: 12/07/2011
Corresponding author
T J Hossain
Department of Biochemistry and Molecular Biology, University of Chittagong, Chittagong-4331, Bangladesh
tanim.bmb@gmail.com