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The effect of breed and stage of lactation on the microbiological status of raw milk
37-45Views:296The 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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The effect of keeping technology on the microbiological status of raw milk
67-75Views:100The importance of the quality of raw milk increased after Hungary had joined to the EU. On delivery of raw milk, the microbiological quality, especially total plate count of the milk is very important. Twenty-two farms (7 large, 4 medium-sized, and 11 small farms) were included in the study. We considered the different farm size, keeping- and milking circumstances during the selection of farms. The examined large farms use loose housing system (cubicle, deep litter) and milking parlour. Most of them use preand post-milking disinfection. In the medium-sized farms, loose,
deep litter and tie-stall housing system, as well as milking parlour, pipeline milking and bucket milking occurred. All of them use preand post-milking disinfection. Small farms use tie-stall housing system, bucket milking and udder preparation by water. Unfortunately, they do not use pre- or post-milking disinfection. In the large and medium-sized farms mainly Holstein Friesian, in the small farms Hungarian Simmental breeds can be found.
The aim of our research was to examine the microbiological status of the raw milk produced in dairy farms (total plate count, coliform count, Escherichia coli count, Staphylococcus aureus count, psychrotroph bacteria count, furthermore yeast and mold count); sources of the contamination; connection between the microbiological quality of produced milk and housing-, milking technologies of farms; furthermore the hygienic circumstances of milking and milk handling of the farms, by the examination of coliform bacteria and Escherichia coli contamination.
During the examination of the connection between the different farm sizes, various housing- and milking forms and the microbiological characteristics we observed similar tendencies in the case of total plate count, coliform count, yeast and molds count, furthermore psychrotroph bacteria count. The value of these parameters was significantly higher in small farms, and infarms which use tie-stall housing forms, bucket milking, udder preparation with water, and which do not use pre- and post-milking disinfection.
The results showed that besides cooling, the milking procedure and the type of udder preparation had the largest effect on the total plate count. Statistical analysis shows that in medium and small farms the combination of pipeline milking – tie stall housing system – disinfectant preparation of the udder; in large farms the combination of milking parlour – loose cubicle housing system – dry preparation of the udder are the most appropriate in the aspect of the total plate count. We experienced that in farms where the hygienic instructions are not followed – and therefore
equipment used during the milking and handling of milk is very contaminated – or rather the separation of mastitic cows’ milk is not appropriate, different microorganisms may contaminate the produced milk. -
The Relationship Between the Moisture Content of Sweetcorn Raw Material and the Quality of the Deep-Frozen End Product
135-139Views:71One of the remarkable effects of the economical and social development is the changing of the eating habits, first of all increasing consumption of deep-frozen products. The spreading of the sweet corn under these vegetables is characteristic.
The parameters exerting influence on the quality of the deepfrozen sweetcorn is classed in 3 categories:
• Physical quality: foreign matter, clumps, blemished corn, broken kernel, miscut, pulled kernel.
• Organoleptical features: taste, colour, texture, and sweetness.
• Microbiological features: TVC, mould, yeast.
The moisture content of the raw material influences the organoleptical features to the highest degree.
We take continuously samples from the raw material arriving in to the factory to determinate moisture content, and from the product to specify the organoleptical features.
Based on the data of 2002 we can make the following findings:
The colour of the deepfrozen sweetcorn is less influenced by the moisture content. The taste is between 69% and 72% the most optimal, but over 72% get worse, more „milky”, water-tasted because of the underdevelopment of sweetcorn. The texture continuously becomes better with the increasing of moisture content. Under 67% of water the class „C” is typical, which means a taste with weak charasteric, a bit scathing or bitter, and texture with rubbery inner part and hard pericarpia. The decadence of taste is caused by converting a great part of sugar into starch.
The correlation between moisture and quality is varying by varieties; different varieties have their best quality by different moisture content. By our investigations the best harvest time is at the 69-72% moisture content. At this point are the organoleptical features the most optimal, and the grower has not the loss of yield caused by early harvesting. -
Variations in major quality parameters of forage and medium quality winter wheat varieties in storage
249-254Views:92We analysed five parameters (moisture-, protein content, Hagberg’s falling number, wet gluten content and alveographic W (10-4 J) values) and the microbiological changes of four forage and milling III. quality winter wheat varieties (Magor, Hunor, Róna and Kondor) during storage, to determine the tendency, type and volume of the of the change of this five qualitative parameters during storage.
We found that the examined winter wheat varieties retained their moisture, protein content and their Hagberg’s falling number, they did not change during storage.
A slight growth could be experienced in the values of wet gluten content for all the four winter wheat varieties in terms of the duration of storage (129 days). This result proved the theory of after-ripening, when gluten percentage improves qualitatively and quantitatively as well. The value of the quantitative growth was about 10% for all the four winter wheat varieties.
We placed a special emphasis on measuring the alveographic W (10-4 J) values during storage. All the four winter wheat varieties showed decreasing values of about 20-40%.
Microbiological examinations on the four winter wheat varieties showed that mould, mould flora and total germ count remained balanced with some slight variations and they did not change in terms of time under optimal storage conditions. -
Microbiological status of bulk tank milk and different flavored gomolya cheeses produced by a milk producing and processing plant
73-78Views:228The microbiological quality of milk is important not only for food safety, but it can also influence the quality of dairy products. In this study, our aim was to assess the microbiological status of the bulk milk of a milk-producing farm, and some natural and flavored (garlic, dill, onion) gomolya cheeses made from pasteurized milk produced by their own processing plant. We determined the number of coliform bacteria, Escherichia coli, Staphylococcus aureus, and molds of three milk and eight cheese samples. The tests were conducted between July and September, 2017.
In bulk milk, the mean coliform count was 3.83±0.17 log10 CFU/ml; the mean E. coli count was 1.38±0.14 log10 CFU/ml; the mean mold count was 3.74±1.30 log10 CFU/ml; and the S. aureus count was <1.00 log10 CFU/ml, respectively. The mean coliform count in gomolya cheeses was 3.69±1.00 log10 CFU/g; the mean E. coli count was 2.63±0.58 log10 CFU/g; the mean S. aureus count was 3.69±1.35 log10 CFU/g and the mean mold count was 1.74±0.37 log10 CFU/g. The amount of coliforms detected in different flavored gomolya cheeses were significantly different (P<0.05). More than 10 CFU/g of E. coli was found only in the dill flavored cheeses, and S. aureus was found only in dill (3.66±1.86 log10 CFU/g) and onion (3.71±0.52 log10 CFU/g) flavored gomolya cheeses. Based on the obtained results, it was found that the amount of coliform bacteria and E. coli in bulk milk exceeded the limit set in regulation of the Hungarian Ministry of Health (MoH) 4/1998 (XI. 11.) and the amount of S. aureus was below the limit. For gomolya cheeses, the S. aureus count exceeded the limit. The amount of coliform bacteria remained above the limit in cheeses, except for the garlic flavored gomolya cheese. In cheeses, a larger E. coli count was detected than in the bulk milk, but there is no specific limit for cheeses in the regulation. The mold count exceeded the limit specified in the regulation in cheeses, but a lower value was detected relative to milk.
The results show that, in the case of bulk milk and gomolya cheeses, certain detected quantities exceeded the limit values set forth in regulation of MoH 4/1998 (XI. 11.). The results indicate an inadequate microbiological state of the raw material and the finished products. The reasons for these are due to reduced technological hygiene or the inappropriate handling of raw material and finished products. In this study, we have summarized the results of our preliminary studies, which can provide a basis for further hygiene studies.
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The effect of season on the microbiological status of raw milk
95-99Views:117Many factors can influence the microbiological quality of raw cow’s milk. In this study, our aim was to determine whether there was any difference between the microbiological statuses of milk produced in different seasons. Samples were collected and analysed from five dairy farms in Hajdú-Bihar County, from February to November in 2019. During our studies, total plate count (TPC), coliform count and Staphylococcus aureus count of raw cow’s milk samples were determined.
There was no significant difference (P>0.05) between the mean TPC values detected in the milk collected in winter and autumn, but that values were significantly (P<0.05) lower than in the milk samples collected in spring and summer. Similarly to the TPC, in the case of coliform bacteria the lowest mean colony count was detected in the samples collected in winter. The difference was significant (P<0.05), compared to the values observed in the samples collected in summer. S. aureus was detected in bulk milk of only two farms in excess of 1.0 log10 cfu/ml. Also in case of S. aureus, there was a significant difference (P<0.05) between the values observed in the samples collected in winter and in summer. Samples from spring and summer contained the highest amount of S. aureus.
Based on the results of our studies, in the case of almost all farms the mean TPC, coliform and S. aureus counts were lower in the samples collected in winter, than in the samples collected in summer. The fact that the samples collected in winter contained the lowest amount of colonies could be attributed to the inhibition of growth of mesophilic microorganisms below 8 °C. Furthermore, the fact that we observed the highest colony counts in samples collected in summer, can be related to the heat stress of cows during the summer due to unfavorable weather conditions (high temperature and humidity).
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Effects of some herbicides on the microbiological characteristics of soil nitrogen cycle under maize plantation
93-100Views:71Nitrogen is a key element for the living organisms and influence not only for the quantity but for the quality of the yield, considerable. Availability of nitrogen from the soil is influenced by several microbiological processes of the Nitrogen-cycle. Among the intensive agricultural production the herbicide application cannot be omitted more information needs therefore about the inhibitor effect of herbicides on the different microorganisms.
An experiment was set up on calcareous chernozem soil under maize culture. Effect of four different herbicides (Acenit, Frontier, Merlin, and Wing) was investigated. The effect of herbicides was measured to four microbiological parameters of the Nitrogencycle (abundance of nitrifying bacteria, nitrate solubilisation, biomass nitrogen and urease enzyme activity). There were singledouble- and five times of recommended doses of herbicides applied for two onsecutive vegetation periods.
From the results of the different doses of herbicides, the following can be stated:
– The Acenit has a stimulating effect on nitrifying bacteria in general. The Frontier and Merlin also influenced the quantity of nitrifyers, however in certain cases decreased in another cases increased the number of bacteria.
– The double doses and five times doses of herbicides was found to be increasing the nitrate content of soil, -especially in 2006.
– The quantity of microbial biomass nitrogen increased in the 60% of treatments and decreased in the 40% of the treatments.
– Except of the result of Wing in 2006 and Merlin in 2005, the effect of simple dose herbicides was the smallest on the urease enzyme activity. According to the results the effect of Merlin was positive; the effect of Wing was negative on the soil enzyme’s activity.
Regarding the application of four different herbicides in three different doses on the microbiological parameters of soil (at two consecutive years-) in 39% of the treatments has resulted a significant inhibitory effect, 28% of the treatments, however have significant stimulating effect on the parameters measured. More than 50% of the inhibitory effect was measured in case of the Wing, at more than 50% of the Frontier the microbiological parameters have not changed. -
The effect of herbs on the microbiological stability and nutritional quality of pariser
101-104Views:89The purpose of this study was to evaluate the functional properties of dried herbs (Thymus vulgaris L., Origanum vulgare L., Salvia officinalis L.) to improve the quality characteristics and microbiological stability of Hungarian meat product, pariser. The addition of herbs did not affect the microbial properties of the product. According to the Decree No. 4 of 1998 of the Ministry of Health, pariser can be considered safe. The nutritional quality of the different forms of pariser was also acceptable. However, the addition of oregano, sage and thyme changed the flavor characteristics of the parisers and the higher meat content would increase the final price of the product.
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Microbiological quality of bulk tank raw milk from two dairy farms in Hajdú-Bihar County, Hungary
105-112Views:290Two 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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Búzaminták fungicid szermaradvány ellenőrzése és gombafertőzöttségének kimutatása
45-51Views:74To protect crops with chemicals against different microorganisms are very important because residues of toxins could pollute infected grains. This could have the meaning of serious danger to the human and animal health. Similarly important is knowledge of details about presence or absence of any practically applied protective compounds. Experimental studies were performed on fungicide treated cereals of the Cereal Research Non-Profit Company, Szeged. Chromatographic methods were used (GC and some GC-MS) to find low level fungicide residues, microwave-assisted isolation of ergosterol was followed by HPLC to detect possible fungal infections and a more detailed microbiological analysis completed the work. Concerning the dry year 2000, no fungicides were found in the samples (by November), the ergosterol level was found to be less than 8 ppm, meaning good quality, coupled with an extremely low level of fungal infections. This was confirmed by direct microbiological testing. In comparison with the microbiological results from 1999, a negative difference can be recognized, most probably due to the rainy weather throughout the year.
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Microbiological and Chemical Characterization of Different Composts
106-111Views:68Composting of agricultural waste is considered particularly important from the point-of-view of environmental protection. Degradation of organic substance results in a significant reduction of waste volume.
The end product of the composting process, mature compost, can be used as soil coverage against excess loss of wastes, for mulching, for organic manure etc. The problem of composting has come into limelight in environmental studies and in agriculture.
The quality of the mature compost is determined by physical, chemical and biological parameters of the composting process which, in turn, depend on initial composition of the raw materials, the technology, e.g. regular mixing and moistening and on environmental factors. Quality is the key question in compost use.
We studied the composting process in compost windrows of different raw material composition. We measured temperature, humidity content, pH, organic substance content, nitrogen and carbon content.
We counted the number of bacteria, microscopic fungy, ammonifying and cellulose decomposing microorganisms. We directed the composting process with turning weekly (to provide oxygen) and watering (to provide humidity content 40-60%).
We set up windrows of 1 m3 volume from dry plant substances (cornstalk, pea straw, tomato stalk and crop, weeds) and cow manure not older than 1 week. The cow manure was used at ratios of 0%, 35%, 50%, 65% and 100%, respectively.
We measured changes in compost temperature relationship with outside temperature until they were almoust the same. Humidity was 40-60% in most cases.
At the beginning of the process, pH was slightly acidic-neutral; it later becomes neutral-slightly alkaline (pH: 6.93-8.02) as ammonia is liberated from proteins.
At the end of the process, pH decreased again, due to humification.
Organic substance content decreased as microorganisms mineralized them. Organic carbon content decreased gradually due to microorganisms used it as an energy.
Total nitrogen content increased until middle of july and decreased gradually until than.
The carbon/nitrogen rate were higher in the beginning, it decreased until july-august and increased by smaller degree until end of the process.
The number of bacteria was higher in the first three weeks and between june-september. The number of cellulose degrading bacteria was the highest in the first three month, the number of ammonifying bacteria was the highest from the end of may until sepember.
The number of microscopic fungy was significant in the second part of process, after july. -
Microbial assessment of potential functional dairy products with added dried herbs
59-63Views:114The market of dairy products is a dynamically developing sector of the food industry. Potential, functional dairy products, made by adding herbs or spices, will have antimicrobial and antioxidant effect due to the active biochemical agents of the plant additives. Furthermore, these active components will widen the storage life of food products and enhance their organoleptic properties too. We worked out a technology for creating fresh cheeses using a gentle pasteurizing method by treating the mixture of raw milk and 1.5% fat contained in commercial milk. As herb additives, we used citronella (Melissa officinalis), and peppermint (Mentha x piperita) harvested by us and dried them via Tyndall-method in convective dryer on 40 °C for 5.5 hours per day. The drying period took three days. We bought dried citronella and mint from the supermarket, which were dried by ionizing radiation, to compare the microbiological pollution with the herbs dried by us.
The main target of this research was to create a microbiologically stable, potential functional dairy product. However, because of the bad quality of the raw milk and the gentle heat treatment we used for sterilizing bulk milk, or else, cheeses were not safe for human consumption. As a consequence, we need further studies to modify our technology and get a microbiologically stable product.
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Examination the effects of different herbicides on the soil microorganisms of a calcareous chernozem
121-126Views:74Pesticides play a key role in fighting weeds, pests and parasitic fungi. According to surveys, pests reduce the yield of agricultural crops by 35% worldwide. Pests, fungi and weeds account for 14%, 12% and 9% yield loss, respectively (Gáborjányi et al., 1995). Chemicals have contributed to increasing and maintaining the yields of crop production for decades. Today, agricultural production (in spite of many efforts) is unthinkable without the use of pesticides (herbicides, insecticides and fungicides). On the other hand, these chemicals contribute to the pollution of the atmosphere, surface and underground waters, and agricultural soils, especially if they are applied improperly.
The sustainable agricultural production pays attention to environment-friendly cultivation-technologies; but at the same time it makes an effort to produce good quality and economical products. The examination of the herbicides’ secondary effects, fits into this chain of idas namely, how the herbicides affect – stimulating or inhibiting – the soil microbiological processes, prevention of soil fertility.
In the course of the experimental work the effect of herbicides on soil biological properties were examined in different maize (Zea mays) cultures. We wanted wished to know that how the herbicides affect the quantity change of soil microorganisms, the life of different physiological groups of bacteria and the activity of microorganisms. A small pot experiment was set up in 2008 with the application of two herbicides - Acenit A 880 EC and Merlin 480 SC – in the breeding house of the Department. The moisture content and nutrient supply were at optimal level in the experiment.
On the basis of results the following can be stated:
1. It can be stated that the two herbicides and all their doses affected negatively the number of total soil bacteria, the
inhibiting effects were significant. The quantity of microscopical fungi increased by the effect of Merlin 480 SC and decreased in the treatments of Acenit A 880 EC.
2. The Acenit A 880 EC had stimulating effect on the nitrate mobilization. The CO2-production was stimulated by the basic doses of herbicides; the other treatments did not influence the CO2-production significantly.
3. The quantity of microbial biomass-carbon –except for only one treatment- decreased significantly by the effect of herbicides. Besides it, the quantity of microbial biomass-nitrogen increased significantly in the treatments of Acenit A 880 EC.
4. The biomass of test plant decreased in the treatments of herbicides, their quantities were smaller than in the control. In the pots treated by Merlin 480 SC, parallel with the increase of doses decreased the quantity of plant-biomass.