Microbiota found in raw milk : their origin and importance for cheese production
The microflora in milk has various different functions that affect the quality of the cheese. The tradition of making cheese is very old and for most of that time cheese has been made without adding bacteria. The aim of this essay is to summarize how the natural bacteria in the raw milk affect the q...
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| Format: | M2 |
| Language: | Inglés Swedish |
| Published: |
SLU/Dept. of Food Science
2016
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| Subjects: |
| _version_ | 1855571534239760384 |
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| author | Dunge, Alice |
| author_browse | Dunge, Alice |
| author_facet | Dunge, Alice |
| author_sort | Dunge, Alice |
| collection | Epsilon Archive for Student Projects |
| description | The microflora in milk has various different functions that affect the quality of the cheese. The tradition of making cheese is very old and for most of that time cheese has been made without adding bacteria. The aim of this essay is to summarize how the natural bacteria in the raw milk affect the quality of the cheese and to compare the differences between raw milk cheeses and pasteurized milk cheeses. This was achieved by studying literature on the subject and concluding the gathered data. The results show that various bacteria that can grow in milk may affect the cheeses in numerous ways. The ones mentioned are: lactobacillus, lactococcus, streptococci, leuconostoc, enterococci, propionibacteria, clostridia and psychrotrophic bacteria. These bacteria originate from various sources; for example, from the surrounding environment, the feed of the animals and from the animal itself. These bacteria may affect the cheese in numerous ways. Firstly, they can affect the cheese positively: e.g. by improving taste, texture or aroma. Secondly, they can also affect cheese negatively: e.g. giving rise to unwanted taste and defects like gas blowing. Due to these bacteria being killed during pasteurization there is a difference between raw milk cheese and pasteurized milk cheese, mainly in taste. For example, raw milk cheeses generally have a more distinct flavor but they also come with the risk of having harmful or even deadly pathogens in them. On the contrary, pasteurized milk often has a milder taste. Furthermore, there is also a higher degree of uniformity between batches due to the fact that the microflora in them is consistent, and therefore gives similar results each time. To conclude, it is difficult to determine which type of cheese that is optimal. It all depends on the purpose of the cheese and the preference of the consumer - something that can be heavily influenced by culture. |
| format | M2 |
| id | RepoSLU9515 |
| institution | Swedish University of Agricultural Sciences |
| language | Inglés swe |
| publishDate | 2016 |
| publishDateSort | 2016 |
| publisher | SLU/Dept. of Food Science |
| publisherStr | SLU/Dept. of Food Science |
| record_format | eprints |
| spelling | RepoSLU95152016-09-13T14:48:28Z Microbiota found in raw milk : their origin and importance for cheese production Microbiota i mjölkråvaran : dess ursprung och betydelse för ostproduktionen Dunge, Alice microorganisms milk cultures milk cheese cheese production pasteurization raw milk cheese cheese quality cheese ripening The microflora in milk has various different functions that affect the quality of the cheese. The tradition of making cheese is very old and for most of that time cheese has been made without adding bacteria. The aim of this essay is to summarize how the natural bacteria in the raw milk affect the quality of the cheese and to compare the differences between raw milk cheeses and pasteurized milk cheeses. This was achieved by studying literature on the subject and concluding the gathered data. The results show that various bacteria that can grow in milk may affect the cheeses in numerous ways. The ones mentioned are: lactobacillus, lactococcus, streptococci, leuconostoc, enterococci, propionibacteria, clostridia and psychrotrophic bacteria. These bacteria originate from various sources; for example, from the surrounding environment, the feed of the animals and from the animal itself. These bacteria may affect the cheese in numerous ways. Firstly, they can affect the cheese positively: e.g. by improving taste, texture or aroma. Secondly, they can also affect cheese negatively: e.g. giving rise to unwanted taste and defects like gas blowing. Due to these bacteria being killed during pasteurization there is a difference between raw milk cheese and pasteurized milk cheese, mainly in taste. For example, raw milk cheeses generally have a more distinct flavor but they also come with the risk of having harmful or even deadly pathogens in them. On the contrary, pasteurized milk often has a milder taste. Furthermore, there is also a higher degree of uniformity between batches due to the fact that the microflora in them is consistent, and therefore gives similar results each time. To conclude, it is difficult to determine which type of cheese that is optimal. It all depends on the purpose of the cheese and the preference of the consumer - something that can be heavily influenced by culture. Mikrofloran i mjölk har många olika funktioner som påverkar ostens slutliga kvalitet. Det finns en lång tradition av att tillverka ost och länge har man gjort ost utan att tillföra extra bakterier. Syftet med detta arbete är att sammanfatta hur mjölkens naturliga bakterieflora påverkar ostens kvalité och att jämföra skillnader mellan ostar tillverkade av opastöriserad mjölk och ostar gjorda av pastöriserad mjölk. Detta sker genom sammanställning av litteratur som berör ämnet. Resultatet av denna litteraturstudie visar att det finns många olika bakterier som kan existera i mjölk och dessa kan påverka osten på olika vis. Dessa bakterier inkluderar: lactobacillus, lactococcus, streptokocker, leuconostoc, enterokocker, propionsyra bakterier, klostiridier och psykrotrofer. Dessa bakterier kan komma från en stor variation av källor: från den omgivande miljön, utfordringen av djuret eller från djuret själv. Dessa bakterier påverkar osten på olika vis. De kan bidra med positiva effekter såsom förbättrad smak, textur och aromer men även negativa effekter så som oönskade smaker och defekter t.ex gasbildning. Eftersom de flesta av bakterierna dör under pastöriseringen uppstår skillnader mellan ostar gjorda på opastöriserad respektive pastöriserad mjölk, framförallt i form av smakskillnader. Opastöriserad mjölk har ofta en starkare, mer karaktäristisk smak men det finns risker att patogener, som kan vara hälsoskadliga och i vissa fall till och med dödliga, kan finnas i mjölken. Ost tillverkad av pastöriserad mjölk har däremot inte samma intensiva smak utan, generellt sett, en mildare smak. Pastöriserad mjölk resulterar i ost som även är mer säker eftersom patogener är eliminerade. Ostar gjorda på pastöriserad mjölk blir även mer uniforma då man kan kontrollera exakt vilka bakterier som tillsätts vilket ger samma resultat mellan ystningar. Det är trots detta svårt att säga vilken ost som är den bästa. Allt beror på vad som vill uppnås med osten och vad konsumenten vill ha - något som kan variera beroende på vilken kultur man befinner sig i. SLU/Dept. of Food Science 2016 M2 eng swe https://stud.epsilon.slu.se/9515/ |
| spellingShingle | microorganisms milk cultures milk cheese cheese production pasteurization raw milk cheese cheese quality cheese ripening Dunge, Alice Microbiota found in raw milk : their origin and importance for cheese production |
| title | Microbiota found in raw milk : their origin and importance for cheese production |
| title_full | Microbiota found in raw milk : their origin and importance for cheese production |
| title_fullStr | Microbiota found in raw milk : their origin and importance for cheese production |
| title_full_unstemmed | Microbiota found in raw milk : their origin and importance for cheese production |
| title_short | Microbiota found in raw milk : their origin and importance for cheese production |
| title_sort | microbiota found in raw milk : their origin and importance for cheese production |
| topic | microorganisms milk cultures milk cheese cheese production pasteurization raw milk cheese cheese quality cheese ripening |