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The effect of breed and stage of lactation on the microbiological status of raw milk
37-45Views:339The microbiological quality of the milk is important not only for food safety, but it can also influence the quality of dairy products. The microbiological status of raw cow milk can be influenced by many factors. Our aim was to determine whether there was a difference between the microbiological quality of milk of two different cow breeds (Holstein Friesian and Jersey) kept and milked in the same conditions, and how the microbiological quality of the raw cow milk changed during lactation (beginning, mid, and end). Samples were taken and analysed in July, August and September in 2018 from two dairy farms in Hajdú-Bihar county. During the conducted studies, the total plate count (TPC), the coliform count, the Staphylococcus aureus count and the coagulase-negative Staphylococcus (CNS) count of raw milk samples were determined.
There was no significant difference (P>0.05) between the milk of the Holstein Friesian and Jersey breeds in the case of TPC. However, the mean coliform count of milk samples taken from Holstein Friesian cows was significantly lower (P<0.05) than the mean coliform count of milk samples taken from Jersey cows. S. aureus was detected in one of the twelve milk samples taken from Holstein Friesian cows, and in two of the eleven milk samples taken from Jersey cows. CNS was found in larger amount in milk samples taken from Holstein Friesian cows, and the difference was significant (P<0.05). Both TPC and CNS count were significantly higher (P<0.05) in individual milk samples taken at the end stage of lactation, than in samples taken in the earlier stages of lactation from Farm “A”. However, in the case of Farm “B”, there was no significant difference (P>0.05) in colony counts at different stages of lactation. S. aureus was only present in milk samples that collected from cows, which were at the beginning and middle stages of lactation. Testimg the hemolysin production ability of S. aureus strains isolated from the raw milk samples, only weak hemolysis was observed on blood agar. In case of antibiotic resistance testing, it was found that all strains were susceptible to cefoxitin, chloramphenicol, clindamycin, erythromycin, gentamicin, penicillin G, tetracycline and trimethoprim/sulphamethoxazole.
Based on the results of our studies, staphylococci were detected in a higher amount in the milk of Holstein Friesian cows, and coliform bacteria were detected in a higher number in the milk of Jersey cows. Summing up the results of the milk samples taken from the different stages of lactation in one of the farms, it can be concluded that higher TPC and CNS count could be detected at the end stage of lactation than in the samples taken from the earlier stages of lactation. The fact that at the end of lactation the microorganisms could be detected in a higher colony count may be related to the fact that teats could be damaged during lactation by the milking machine, which increased the chance of imvading the microorganisms into the udder.
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Bacteria in the milk of sheep with or without mastitis- mini Review
47-52Views:373From a nutritional point of view, sheep milk is more valuable than cow and goat milk and the interest for sheep milk is increasing in many countries. However, sheep milk is easily contaminated during milking, handling, and transport and it is an ideal medium for bacterial propagation. Consequently, sheep milk spoils quite quickly. The proper, clean handling of milk is not only of sanitarian interest, but it also serves the farmers’ interests, because contaminated milk may not be distributed, and is unsuitable for producing good quality products. Following this technological trend, this review addresses the bacterial composition of sheep milk with and without mastitis. Even though sheep milk contains a lot of bacteria, this review article highlighted total plate count, Enterobacteriaceae, coliform, Staphylococcus aureus, Escherichia coli, Listeria monocytogenes, Campylobacter, Salmonella spp. and Streptococcus spp. Mastitis in sheep is a vital cause of mortality, reduction in milk production and early culling. The reported risk factors for mastitis in sheep were age, a case of mastitis, breed, husbandry systems, and location. The main priority should be implementation of programs to minimize human pathogenic bacteria and mastitis in raw ewe milk.
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Identification of cow’s and buffalo’s milk and dairy product using a DNA-based method
279-282Views:246Aim of our study was the optimization of a DNA method, that is appropriate for reliable, low cost identification of animal species in milk and dairy product (cheese) and to determine the ratio of species. Mitochondrial DNA was used in our work to analyse buffalo/cow milk mixtures contained different ratio of bovine milk such as 0.1%, 0.5%, 1%, 1.5%, 2%, 5%, 10%, 15% (v/v%). Buffalo cheese were produced using buffalo and cows milk (0%, 2%, 5%, 10%, 15% – v/v% cows milk in buffalo milk). In case of milk mixtures, using species specific primers, the PCR assay showed a 0.5 v/v% detection limit. Cattle, in the buffalo/cows milk 99.9/0.1 v/v% mixture, was not detectable. The identification of buffalo and cows DNA in cheese was successful. The intensity of eletroforetic PCR fragment indicated the increase of cow milk ratio in milk and cheese samples as well.
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Microbiological quality of bulk tank raw milk from two dairy farms in Hajdú-Bihar County, Hungary
105-112Views:327Two main channels have been identified to be responsible for microbiological contamination of raw milk and milk products. Firstly, contamination has occurred due to udder infection from the cow or the blood which harbours most bacteria that come in contact with the raw milk. Secondly, via external factors (may include faeces, skin, contaminated water, environment etc.) which are associated with the operation of milking. There is direct contact with the milk and/or surfaces before, during or after the milking, posing public health risk and economic decline. The aim of this study was to examine the bacteriological quality of bulk tank raw milk samples collected from two different size dairy farms (Farm 1 and Farm 2) of different housing forms (cubicle loose and deep litter) in Hajdú-Bihar County, Hungary in July, 2017. Three samples were taken from each farm, and the total plate count, coliform count, Escherichia coli count, Staphylococcus aureus count, and yeast and mould count were determined in them.
The results clearly showed low level of all measured bacteria group load in Farm 1 samples in comparison to Farm 2 with the exception of coagulase-negative Staphylococcus (CNS) which represented high level in general, indicating significant difference (P<0.05). The mean value of total plate count in Farm 2 samples was higher (1.0 × 105 CFU/mL) than Farm 1 samples (2.8 × 104 CFU/mL). There was a significant difference (P<0.05) in mean count of coliforms in raw milk samples between Farm 1 and Farm 2. Similarly, results of E. coli were significantly different (P<0.05) with mean count of 1.44 × 102 CFU/mL and 2.02 × 103 CFU/mL for Farm 1 and Farm 2 respectively.
Results of Staphylococcus aureus also showed significant difference (P<0.05) with mean count of 9.7 × 101 CFU/mL for Farm 1 and 6.28 × 102 CFU/mL for Farm 2. The mean of mould count recorded was 1.07 × 102 CFU/mL and 4.93 × 102 CFU/mL for Farm 1 and Farm 2 respectively. The recorded mean of yeast count was 1.68 × 103 CFU/mL and 3.41 × 103 CFU/mL for Farm 1 and Farm 2 respectively; however, both farms showed no significant difference (P>0.05) in terms of mean of mould and yeast count. Although Farm 2 produced six times lower milk quantity than Farm 1, the measured microbial parameters were high. Both farms’ microbiological numbers were higher above the permitted limit values as stated by Regulation (EC) No 853/2004, Hungarian Ministry of Health (MoH) 4/1998 (XI. 11.).
This could be an indication of non-conformance to effective GMP, ineffective pre–milking disinfection or udder preparation, poor handling and storage practice, time and temperature abuse and inadequate Food Safety Management System Implementation. Therefore, our recommendation is as follows; establish control measures for pre- and postharvest activities involved in the milking process which would be an effective approach to reduce contamination of the raw milk by pathogenic microorganisms from these farms, strict sanitation regime and hygiene protocol be employed and applied to cows, all equipment, contact surfaces and minimize handling of the milk prior, during and after milking. This will also serve as scientific information to the producers for continual improvement in their operations.
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Complex problem analysis of the Hungarian milk product chain
43-47Views:103Hungarian dairy sector went through significant changes in past two decades. The most significant changes were caused by our accession to the European Union. In Hungary milk production remarkably declined after EU accession. The size of our dairy herd has been practically reducing since the political transformation, but increasing yields per cow could compensate it in some way and for some time. However, in recent years, increasing yield per cow came to a stop and in parallel, the number of cows declined further and faster. Low prices, high production costs and tightening quality requirements ousted several producers from the market in past years. Feeding cost represents the highest rate in cost structure of production, but animal health expenditures and various losses are also significant. There are undeniably competitive disadvantages in the level of organisation and labour productivity; however competitiveness already depends on cost effectiveness in the medium run. In Hungary concentration of the dairies is relatively strong in spite of the relative high number of corporations. The dairies compete with each other and with the export market for the raw material and the better exploitation of their capacities. Applied technology of the Hungarian dairies lags behind the Western-European competitors’; in addition they have handicaps in efficiency and product innovation. Presence of chain of stores being dominant in sale of milk products does also not favour in all respects to the position of the dairies. The aforementioned retail chains are namely consumer-centric, engage in price follower conduct and weaken the position of the dairies with their private label products. As a result of increasing import of milk and milk products Hungary became a net importer in recent years. Today, disposable income still essentially determines the consumption habits of price-sensitive consumers. Loyalty for Hungarian products is not typical, consumers are open for import products being preferred by retail chains. In addition Hungarian milk and milk product consumption is about half of the Union average and it is far behind the level being necessary for healthy eating. In Hungary lack of competitiveness and vertical integration relationships and backwardness are revealing among the dairy farmers and the dairies, while chain of stores are in unprecedented “monopolistic situation”; the whole sector can be characterised by defencelessness.
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Effect of using antioxidants as feed additives in the diet of dairy cows on the vitamin E and lycopene content of milk
69-72Views:141In 2007, the aim of an Ányos Jedlik program and call for tenders was to support application-oriented, strategic research and development projects, which can increase the competitiveness of the Hungarian economy. In the framework of our project, we intended to examine whether non-protected antioxidants – in this case: vitamin E and lycopene – used as feed-additives can increase the antioxidant content of milk. The milk with an
increased level of vitamin E and lycopene content can be used for producing functional foods which will represent competitive products on the current market of milk products. Our results show that the use of vitamin E as feed-additive can significantly increase the amount of vitamin E in the milk. The use of lycopene as feedadditive also gave good results. At the beginning of the experiment, the lycopene content of the milk was below the detection limit, while in the post-feeding milk samples the lycopene became detectable. Based on our results, we are of the opinion that further experiments and analyses are needed regarding the quality of food of animal origin and animal health. -
Effect of vitamin e and selenium supplementation on the antioxidant content of milk and dairy products in dairy cows
9-12Views:153In 2007, the aim of the Ányos Jedlik program and the call for tenders was to support application-oriented, strategic research and development projects, which can increase the competitiveness of the Hungarian economy. In the framework of our project, we intended to examine whether non-protected antioxidants - in this case: vitamin E and selenium – used as feed-additives can increase the antioxidant content of milk. The milk with an increased level of vitamin E and selenium content can be used for producing functional foods which will represent competitive products on the current market of milk products. Our results show that the use of vitamin E and selenium as feedadditives can significantly increase the amount of vitamin E and selenium in the milk and also in the diary products.
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Macro element contents of different genotype cows’ milk
27-31Views:176The level of mineral elements is important factor regarding the quality of milk. The aim of our research study was to determine the content of mineral elements in milk of Holstein, Jersey, Brown Swiss, Ayrshire, Norwegian-red, Swedish-red cows in the first stage of lactation. All cows were fed with the same type (composition) of feed and they were kept under the same condition. The concentration of macroelements (K, Na, Ca, P, Mg, S) in digested milk samples was determined by inductively coupled plasma optical emission spectrometry (ICP-OES).