Recognition of Adulteration in Milk: A Review
Iqra Bano1, Hira Sajjad2 and Mohammed Zeb khan3*
1Department Veterinary Physiology & Biochemistry SBBUVAS Sakrand, 67210 Pakistan
2 Key Laboratory of Agricultural Animal Genetics, Education Ministry of China, Huazhong Agricultural University, People’s Republic of China
3 Department of Preventive Veterinary medicine, Northeast Agriculture University Harbin China
Submission: December 28, 2018;Published: January 10, 2019
*Corresponding author: Iqra Bano, Department Veterinary Physiology & Biochemistry SBBUVAS Sakrand, 67210 Pakistan, Pakistan.
How to cite this article: Iqra B, Hira S, Md Zeb khan. Recognition of Adulteration in Milk: A Review. Dairy and Vet Sci J. 2019; 8(5): 555750.DOI: 10.19080/JDVS.2019.08.555750
The food debasement is a worldwide problem and emerging nations are at sophisticated risk related with it because to deficiency of specialist care and strategies. Though, it is the greatest common issue that has been unnoticed in numerous countries. Tactlessly, in distinction to common certainty, milk additives can cause various life-threatening issues leading to death of consumers. The current paper grants a comprehensive assessment of common milk alloys as well as various means to perceive the adulterants. Currently milk is being mixed in more sophisticated behaviours that demands proper research for the detection of the adulterants.
Keywords: Milk; Adulteration; Dairy
Abbrevations: FSA: Food and Drug Administration; SCC: Somatic Cell Count; CE: Capillary Electrophoresis; SIA: Sequential Injection Analysis
Naturally, milk has a high nutritious worth as it is a virtuous basis of excellence vitamins, fats, proteins, carbohydrates, and mineral deposits . It is effortlessly consumable and thus it is willingly absorbed particularly significant for toddlers, milching animals, progenies and aged animals. Milk proteins similarly provide amino acids desirable for the appropriate development of grownups and children . Though, if impure, it leads an economic burden on the handler and becomes dangerous to customers by becoming inferior in quality. Like, people sensitive to cows’ milk can suffer severely if they consume ovine or caprine milk tainted by means of bovine milk or else whey . The adulteration of milk is a performance of deliberately dropping its superiority, accessible for sale either by addition of poorer ingredients or by elimination of various appreciated ingredient. It may be either intentional to earn extra money by the addition of extraneous water, non-dairy melamine, proteins, animal fat, urea, re-formed milk, artificial milk or possibly will be mixed with some natural means, like the natural entry of antibiotics into the milk from cattle treated for mastitis, or dust particles or other extraneous objects that might have entered the milk throughout handing out.
Maximum of the times, the debasement of milk is deliberate to make more profit, but then occasionally it may be due to the absence of appropriate perceiving technology in addition misperception due to drug usage practices . Some studies have revealed that following the treatment of mastitis the milking animal shown traces of antibiotic deposits in milk; also in lack of appropriate guideline about the lactation period and improper handling of teats frequently lactation is done in incorrect time with contaminated hands leading antimicrobial remainders in milk (if milking done early) or surplus of milk (if lactation is performed late) . Occasionally ordinary milk is mixed with low cost constituents like whey, water etc. and is recognized as ‘financial adulteration.’ This is a very common practice from the milk traders to enhance water or else ‘fluid-whey’ with milk  furthermore the watery milk decreases its nutritive worth, and polluted water grounds thoughtful health issues. Accumulation of water deviates specific gravity of the milk and its usual appearance gets demolished. To perceive water in milk typically scientific device used is called lactometer by which the alteration in specific gravity is observed . But then again to reimburse the specific gravity, diverse categories of salt besides sugar12 are used . Rarely to hold it colour a minor quantity of dye is also added .
The Maltodextrin are commonly used in dairy diets to improve flavour and decrease the price of the foodstuffs . The additional adulterant commonly used is liquid whey (obtained subsequently creation of cheese by milk). Some manufacturers, for better profit, utilise low-priced muriatic acid to make the whey which grounds solemn fitness issues and require discovery of adulterated milk through whey. The distinctiveness of this debasement is that it is not changing the lactose contented of the milk but then rises its acidity. To reduce its acidity a minor quantity of alkaline solution of sodium hydroxide is added . The elimination of the cream or marketing of scanned or moderately skimmed milk as complete milk is likewise one arrangement of milk debasement. This paper attempts to investigate various milk adulterants and their health dangers.
Milk Adulterant and its Detection
The problem-based learning (PBL) method mimics reallife situations to enhance and stimulate learning, knowledge integration, lifelong learning skills, cognitive, metacognitive, and personal development [8,9] and team work. Furthermore, PBL focuses on the development of problem-solving skills, teambuilding, self-directed and independent learning, communication, interpersonal skills, critical thinking, activation of prior solid knowledge, holistic approach, and self- and peer-assessment abilities [9,10]. In our College, PBL is the basis of Integration and Application courses, where students spend 2-3 weeks on a real clinical case. The ides is to help students understand how the knowledge of anatomy, physiology, pharmacology, pathology, and clinical pathology is integrated and used to come up with the correct diagnosis and treatment of a case.
PBL, in addition to problem solving, also encourages awareness, planning, stress management, reasoning, selfassessment, personal learning preference, creativity, time management. It enrages defining real problems, extending experience, decision making, group and leadership skills, coping with conflicts, and empathy . It also promotes team work, communication, information literacy and lifelong learning. More importantly many of the above skills are essential for everyday practice . PBL aims to develop deep and long learning through higher-order thinking . It was emphasized  that PBL is not “a mere teaching technique but a total approach to education that involves problem design, PBL curriculum development, PBL tutorials, problem-based learning compatible assessments, developing students’ knowledge and capabilities, and is underpinned by the philosophy of PBL.” An integrative view of innovative teaching methods can be clearly seen in suggestions of some investigators  for the name of PBL: “student-centered, problem based, inquiry-based, integrated, collaborative, and reiterative, learning”. However, one must separate PBL and problem-solving learning as the latter focuses on problems in the learning process, while PBL is a welldescribed system of structures and procedures that were first systematized as follows :
a. Students are responsible for their learning.
b. The structure of the problem should allow free inquiry, should stimulate, contextualize, and integrate learning.
c. Learning is multidisciplinary and integrated.
d. Students` Milk Adulterant and its Detections must be based on collaboration and faculty instructors should facilitate it.
e. Students must apply previous knowledge.
f. Self- and peer-assessment is integrated into the learning process.
g. PBL tasks should mimic the real world.
h. Assessment methods should measure the progress toward meeting the goals of PBL.
i. The curriculum should be based on the PBL principles (cumulative, integrated, progressive, and consistent).
Further, PBL tutorial process was described in eight points : Exploring of the problem; identification of previous knowledge; identification of gaps in the knowledge; prioritization of the learning needs; engaging in a self-directed search for knowledge; returning to the group and sharing of the new knowledge; application of the knowledge; and assessment of the learning process and result. Attention must be called to the problem as a provoker of a so-called liminal space, or time between ‘what was’ and ‘what is next’, should be considered when creating problems for PBL . Also, it is emphasized that PBL problems should not be mere “hooks to hang new knowledge on” but they should have the maximal potential to enhance PBL goals . On the other hand, the term “edge of chaos” is a good description for learning and the flow of experience in PBL. In this state of learning/knowledge, creativity, learning, and flow are interacting under agreed upon and frequently reviewed basic rules within the PBL team .
PBL was recommended for introduction into the veterinary curriculum, parallel with other active teaching methods such as interactive lectures and seminar sessions . In addition, students must develop their own learning issues and they should be able to find an answer to the questions and identify missing information . One must note that in some cases  PBL learners scored less points on a traditional, knowledge testing examination, such as the Part I National Board Medical Examination, than learners from the traditional systems. Two major concerns about PBL were expressed : the time PBL requires from the faculty staff who serve as tutors, and the PBL’s efficiency in disseminating large materials in relatively short time frames.
Interestingly, PBL not only exists as a part of veterinary courses or as pilot studies, but there are veterinary schools, such as Purdue University in the USA, that have integrated PBL in their professional curriculum, and used it for years in its Integration and Application courses. Further, at the University of Nottingham’s School of Veterinary Medicine and Science, 20- 30% of the “total teaching delivery” is presented in the form of PBL . Moreover, the College of Veterinary Medicine at Western University of Health Sciences designed an admission process that aims at selecting “students who will succeed in a student-centered learning environment”  and uses PBL in all their courses.
PBL and Second Life
Evaluating a Second Life Problem-Based Learning (PBL) demonstrator project, it was concluded that in Second Life, eight information- or avatar driven scenarios were designed for paramedic and healthcare management education. Students valued the realism and easiness of the scenarios that were more authentic than classroom- based ones .
Problem-Based Writing with Peer-Review (PW-PR)
Although scientific literacy is important, students have only a few opportunities in science-based curriculum to practice scientific writing . Problem-based writing with peer-review (PW-PR) enhances reasoning and therefore reveals the cognitive structure of a physiological problem . The importance of both the subject matter and the organization of the content in meaningful learning must emphasized . More importantly, PW-PR does not replace didactic lectures directly and it is more helpful for motivated students. PW-PR helps in solving complex or integrative problems, synthesizing, and developing combinatory skills, and the lack of all these factors can result in low scoring on exams. The students have found PW-PR an effective learning tool . Use of reflections as assignments in the veterinary courses can enhance problem-based writing.
Self-Directed Learning (SDL)
SDL, which gives the student the choice to take charge of their own learning process (autonomy), has its roots in adult education . Veterinary students are exposed to SDL methods to mimic future clinical experiences. For successful SDL, several skills must be developed: information literacy, time management, evidence-based veterinary practice, and self-assessment. The interdisciplinary approach of SDL is believed to increase the students` deep learning, critical thinking, and interdisciplinary problem-solving abilities .
However, in the development of SDL the following two factors are quoted because they are dominant :
i. “The student’s feelings of being in charge and having a genuine impact on the learning situations are crucial for their desire to take responsibility.
ii. Feelings of being in charge are connected to understanding the demands of the learning context, experiences of managing and getting feedback.”
SDL can be developed within PBL environment. Six competencies that are essential to be self-directed in PBL were identified [16,23]: Self-assessment of learning gaps, evaluation of self and others, reflection, information management, critical thinking, and critical appraisal. When learning in a self-directed way, students must be thinking in a similar way to their instructors; they must identify what, how, why, and for what reason to learn .
Portfolio Building in SDL
The observation of milk excellence is significant for diet protection, as well as for course of the production of dairy products. There are numerous sophisticated approaches such as chromatography and spectroscopy etc. which are used to perceive the milk quality. Moreover, there are many other different bio detecting methods used for recognition of milk adulteration. Like a biosensor which is an exploratory device that in close interaction by a transducer adapts a biological indication into an assessable electrical gesture. The biological constitutes of this device are some enzymes, antibodies, tissues, and receptors. Numerous biosensors are combined by the electrical devices to perceive the milk adulteration. Repeatedly lactose attentiveness acts as an elementary indicator for the assessment of milk superiority and the discovery of irregularities .
The antibiotics in milk
To treat animals against infections like mastitis 80% of dairy herds relay on antibiotic therapy. These antibiotics by means of antimicrobial deposits are present in profusion with in milk . Occasionally these mixtures are correspondingly added to rise the shelf life of milk products . The common antimicrobial medications are tetracyclines, sulphonamides, and nitrofurans antimicrobial remainder  in addition to some beta-lactam drugs like penicillin-G, amoxicillin, cloxacillin, dicloxacillin, cefuroxime and cefoperazone . The Pasteurization and other methods of temperature dealing are very effective for pathogens but have imperfect belongings on drug remainders . The USA food and drug administration (FDA) have investigated around 80 drug remainders in livestock derived human diet . The presence of antimicrobial components in milk can root latent dangers to the customer. Residues of medications in milk lead serious health threats like allergic responses,  upsurge in the amount of antibiotic resistance causes damage to the abdominal flora  and some may possess carcinogenic belongings. Furthermore, it may also cause tissue damage . It restricts in the fermentation of bacterium and cause loss of fermented products. The most viable method to detect antibiotic residue in milk is named as Somatic cell count (SCC) . Moreover, the antimicrobial deposit can be spotted by giving with a biochemical reagent .
Addition of Colour in Milk
Numerous food colorants are correspondingly added which have dangerous consequence on health. The investigative technique named as capillary electrophoresis (CE) is done for the parting of diet colorants. CE method stretches a minor sample volume and visual pathway. The finding limit is disappointing .
Use of Preservatives
The growth of microorganism causes destruction in its structural components and make it un healthy. Generally, the milk comprising bacteria  changes lactose into lactic acid. which in turn fluctuates the electrical restriction of the milk. The conductivity is an easy parameter to perceive bacteria, but it is powerfully influenced by fat percentage of the milk and mainly used to diagnose the mastitis . Moreover, some pesticides are likewise mixed with milk to destroy the germs existing in milk. and to fight its additional development or in other words it acts as a preservative. The pesticides existing in milk can be perceived by method known as mass spectrometry . According to some research Occasionally hydrogen peroxide (H2O2) is also used to preserve milk and E-Tongue technique is used for the detection of H2O2 and fat percentage of the milk . Beside this formalin and Boric acid are regarded as oldest adulterants agents mixed with milk as preservative . It progresses the abdominal discomfort, diarrhea, nausea and further poison associated warning signs. The Rosalic acid test is a very common test to perceive formalin in milk .
Mixing of Urea in Milk
The urea is a very common milk adulterant used to surge its shelf life. Beside this the urea is also used for preparation of artificial milk. The urea components in milk could also rise due to instable nourishing of cows . Unstable urea components in milk causes fertility of dairy cows. Moreover, it is also used for heat constancy . the Health threats related urea are ulcers, acidity, stomach-ache, and tumours. The urea is injurious to kidneys. Liver, heart and many other visceral organs particularly it damages kidneys as they eliminate it from the body . This requires the importance of recognition of urea in milk. The procedures for assessment of urea within milk are consequential from the response of urea by p-dimethyle amino benzaldehyde or else diacetyl monoxime and estimated by ion discriminating electrode . The urea is also perceived by another method known as calorimetric technique . It is also detected by the physical appearance and absorption possess of the amide tie of urea in infrared section .
Addition of Chlorine in milk
Chlorine is mixed with milk to recompense the thickness of the thinned milk subsequently accumulation of liquid. The inflammation of udder in cow also increases the chlorine amount within the milk. The chlorinated milk can root obstruction in blood vessel and progress heart issues . Furthermore, for detection of chlorine in milk the procedure named as sequential injection analysis [SIA] based on titration with silvery cation is done. Moreover, the chlorine recognition in milk is likewise done by titration with potentiometric finding .
Addition of Neutralizers in milk
The neutralizers as sodium carbonate, hydrated lime, sodium bicarbonate or sodium hydroxide, are mixed with milk which are usually banned. The sodium hydroxide is often used in artificial milk to deactivate the acidic consequence . The consumers develop cancer due to the ingestion of milk polluted with sodium hydroxide. The Unreal milk is a usual issue which is organized by addition of some refined oils, caustic soda, and some common cleansing agent. It is shown by some studies that the caustic soda which comprises sodium, turns as slow venom for the heart patients. Because the caustic soda denies the physique from exploiting lysine, an indispensable amino acid present in milk, which is essential for rising babies. Such type of synthetic milk is very destructive for all consumers specially for expecting women .
Though the financial improvement is one of the chief motives for milk debasement, insufficient source this is more common in the emerging and under established states because of deficiency of satisfactory intensive care and law implementation. The Current common recognition methods are not continuously suitable and reachable in these nations making it hard to discourse the varied behaviours of fake sullying in milk. This noises for mutual exertions from systematic societies and the supervisory authorities by proper development, application and broadcasting of improved methods for the discovery of milk debasement. Furthermore, responsiveness and access to evidence can lead dynamic role in these areas to repress this issue. Some of these informal finding methods at the customer level can bring this issue conclusion for the sufferers, counting lots of progenies in the unindustrialized states.
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