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Is high yeast count in cheese bad?

microbiology cheese yeast

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#1 jiljilbean

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Posted 29 May 2019 - 04:31 PM

hey guys,

 

Is having tooooo high a count of yeast in cheese bad?

why is that?

 

 

Thanks



#2 zanorias

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Posted 29 May 2019 - 05:07 PM

Hi jiljilbean,

 

Cheese & it's microbiology are not my area and I'm sure other members will be able to provide more detailed answers. However a google confirms my suspicions that the presence of certain yeasts in high enough populations can affect the quality and cause spoilage.

 

Yeast spoilage may also lead to detectable but non-visible alterations resulting in off-odor and -flavor or texture alterations through the production of ethanol, CO2, and volatile organic compounds (primary and secondary alcohols, aldehydes, esters) as well as the production of lipolytic and proteolytic enzymes (glycolysis)

It was defined that yeasty and fermented off-flavors were detected when yeasts grew at populations equal or above 105–106 CFU/g

https://www.ncbi.nlm...les/PMC5620633/

 

Yeasts and molds may enter cheese from a variety of sources, including the starter culture, ambient air, brine, processing equipment, and workers [5, 34, 39]. Many yeasts can contribute to taste, flavor, and appearance; however, not all species produce beneficial effects, and a species may benefit one cheese while spoiling another. Particular yeasts on the surface of the cheese can cause spoilage or generate undesirable aromas, flavors, or other metabolic products that reduce the quality of cheese [2, 4, 23, 50]. Furthermore, while yeasts are rarely associated with foodborne infections, studies have shown the presence of medically relevant yeast species in various cheeses, including Candida albicans [11, 51], Candida tropicalis [13, 51], C. krusei, and C. glabrata [51].

https://digitalcommo...=foodsciefacpub

 

Can I ask what type of cheese is in question here?

 

Also, just one thread for the topic would be sufficient  ;)



#3 jiljilbean

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Posted 29 May 2019 - 05:55 PM

hey zanorias!

 

thank you for your help!

I do know there are some yeast and mold in cheeses that help out the flavor

 

Its mainly parmesan/Romano cheeses.  (yum yum)

 

All I know when the yeast count is high...it definitely produces gas and stinks....like alcohol/sourish odor.

 

I know I wouldn't eat it. blah!

Thanks again :)



#4 zanorias

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Posted 29 May 2019 - 07:15 PM

Indeed some cheeses depend on yeasts and moulds for flavour (not my cup of tea personally, other than blue cheese dip for fries!)

Anyway, is this a domestic or industry question? If the latter I would certainly investigate why the count is high. One paper I was reading earlier went into detail on potential causes for this, I think it was the second one I linked.



#5 Ryan M.

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Posted 29 May 2019 - 11:21 PM

If you can have an outside lab isolate and give you the genus and species of the yeast organism (the most prominent one) it can help you identify the source.  Also, it will tell you if it is in fact related to the culture or an outside contaminant.

 

Typically, it is contamination of equipment (inconsistent and/or poor sanitation) and air quality problems that create yeast spoilage in cheese.







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