JoAnna Brown

Blue Cheese Development

Blue cheese is thought to have been one of the earliest cheeses produced by allowing moldy bread

to come in contact with the cheese. Blue cheese is a soft cheese and different varieties are made with

either sheep’s or cow’s milk (Anonymous 2010). The cheese is made by pasteurizing the milk product,

cutting and stirring the clumps that form to separate the curds from the whey, adding emulsifiers, and

pressing the curds into blocks (Heiman and Torkelson 2011). Next, the cheese needs to develop its

characteristic clue veins. This is done by either allowing the mold to naturally come in contact with the

cheese in the caves where it’s aged, or by introducing the mold from a culture. Cultures are grown and

allowed to ferment in sterilized milk-based mediums with high osmotic pressure, then high heat is added

to inactivate the mold (Nelson 1970). High pressure has also been shown to reduce the microbial load of

the cheese and may inhibit further undesirable ripening of the cheese (Voigt and others 2010).

When adding the mold to the cheese, needles are used to introduce the mold throughout the

cheese and not just on the outside (Fernandez-Salguero 2004). Normally seeing mold on food doesn’t

entice us to eat it, but the spoilage molds found on cheese are of the Pseudomonas genus of bacteria such

as Pseudomonas fluorescens (Martin and others 2011). The mold typically used to make blue cheese is

Penicillium Roqueforti. The synergy of P. Roqueforti and Yarrowia Lypolytica helps to produce the

distinct blue cheese odor (Gkatzionis and others 2013). Short chain ketones are also responsible for the

distinct aroma of blue cheese. Fatty acids present in the cheese undergo beta-oxidation to form these

ketones (Patton 1950). Different sections of the cheese contain different organic molecules that give

them different scents. The blue and the outer crust of the cheese contain high amounts of ketones

whereas the white is high in alcohols and aldehydes (Gkatzionis 2009).

Along with hydrocarbons and mold, yeasts also contribute to the unique flavor, texture, and

appearance of blue-veined cheeses. In tests, over 74 types of yeasts were found present in blue cheese.

These yeast are the microbiota of blue cheese and contribute to the mold growth as well as taste and

aroma (Alvarez-Martin and others 2007). Geotrichum candidum is a fungal species that has been

characterized as a yeast that consumes lactate and produces enzymes that break down fats and proteins;

this aids in the softening of the cheese and helps develop the texture (Belen-Florez and others 2007).

Different types of bacteria also contribute to flavor, scent, and texture. Almost 95% of the aerobic

mesophile bacteria present in blue cheese is lactic acid bacteria (López-Dı́>az 2000).

In the finished product, the amount and color of the veins determine desirability of the product for

the consumer. A large amount of dark blue veins would produce a strong flavor, where as fewer/lighter

veins would have a weaker flavor. Typically, if the mold is greenish or brownish, consumers will view it

as over-ripened or old. This can happen as a result of improper packaging. If the cheese is allowed to

ripen in a closed package, it will produce CO2. As the carbon dioxide concentration increases, conidial

pigmentation of the Penicillium Roqueforti was affected and caused it to turn greenish brown (Fairclough

and others 2011).

Salt and fat content of the finished product are also important factors to take into account.

Reduced fat content can be linked to increased flavor perception as well as aroma intensity. An increase

in salt content can lead to a lack of cohesiveness in the cheese because the salt leads to an increase in

protein-water interactions and a decrease in protein-protein interactions which would cause a less firm

cheese (Saint-Eve and others 2009). Diethyl succinate can also be added to blue cheese to change the

intensity of its flavors. When present in 500 ppm, a fruity note is brought out in the blue cheese. This

diethyl succinate also can deepen, enhance, and round out the cheese flavors (Wright 2012). Studies

have allowed the production of blue cheese a long way from leaving it by moldy bread, and all of these

factors play a huge part in the preparation of a blue cheese consumers will love.

Blue CheeseReferences

Alvarez-Martin P, Florez AB, Lopez-Diaz TM, Mayo B. 2007. Phenotypic and molecular identification of yeast species associated with Spanish blue-veined Cabrales cheese. Int.Dairy J. 17(8):961-7. Concepts: Yeasts are microbiota for blue-veined cheeses; Yeast growth tolerances; Yeasts contribute to mold growth; Metabolic capabilities aid in taste and aroma; Yeast classification tests; Cabrales; 74 yeasts; Role in dairy

Anonymous 2010. Choosing cheese. Prep.Foods 179(4):39, 41-44. Concepts: Cheese categorization strategies; History of blue cheese; Modern production; Different types of blue-veined cheeses; Roquefort vs. Gorganzola

Belen-Florez A, Alvarez-Martin P, Lopez-Diaz TM, Mayo B. 2007. Morphotypic and molecular identification of filamentous fungi from Spanish blue-veined Cabrales cheese, and typing of Penicillium roqueforti and Geotrichum candidum isolates. Int.Dairy J. 17(4):350-7. Concepts: 35 white and blue-green filamentous fungi in Cabrales; Use of mold in cheese characteristics; Geotrichum candidum function; no P. Roqueforti spores added to Cabrales; Cultures

Fairclough AC, Cliffe DE, Knapper S. 2011. Factors affecting Penicillium roquefortii ( Penicillium glaucum) in internally mould ripened cheeses: implications for pre-packed blue cheeses. Int.J.Food Sci.Tech. 46(8):1586-90. Concepts: Desirable cheese characteristics; Lactose main carbon source; Optimum growth conditions; Relationship of veins and flavor; Mold changes atmosphere within packaging causing discoloration

Fernandez-Salguero J. 2004. Internal mould-ripened cheeses: characteristics, composition and proteolysis of the main European blue vein varieties. Italian Journal of Food Science 16(4):437-45.Concepts: Characteristics of blue cheese; Fatty acids vs. flavor; Openness in texture using Lactococcus lactis; Bacteria present in caves and commercially; Poking with needles allows for mold growth throughout cheese; Manufacturing process of different types of blue cheese

Gkatzionis K, Hewson L, Hollowood T, Hort J, Dodd CER, Linforth RST. 2013. Effect of Yarrowia lipolytica on blue cheese odour development: flash profile sensory evaluation of microbiological models and cheeses. Int.Dairy J. 30(1):8-13. Concepts: Synergy of P. roqueforti and Y. Lipolytica produce cheese odor

Gkatzionis K, Linforth RST, Dodd CER. 2009. Volatile profile of Stilton cheeses: Differences between zones within a cheese and dairies. Food Chem. 113(2):506-12. Concepts: Different sections of cheese (blue veins, white core, and outer crust); Blue and outer crust high in ketones, White high in alcohols and aldehydes; Sporulation and vein formation; Different aromas

Heiman KF, Torkelson TS, inventors; Anonymous 2011 Blue cheese product and process for preparing same.

Concepts: Process for making blue cheese

López-Dı́>az TM, Alonso C, Román C, Garcı́>a-López ML, Moreno B. 2000. Lactic acid bacteria isolated from a hand-made blue cheese. Food Microbiol. 17(1):23-32.Concepts: Nearly 95% of aerobic mesophiles found in cheese are lactic acid bacteria; Lactococci and enterococci predominantly found at beginning stages of processing, enterococci and lactobacilli and leuconostoc present from drying to time of consumption

Martin NH, Murphy SC, Ralyea RD, Wiedmann M, Boor KJ. 2011. When cheese gets the blues: Pseudomonas fluorescens as the causative agent of cheese spoilage. J.Dairy Sci. 94(6):3176-83. Concepts: Microbial spoilage in cheese; Pseudomonas genus bacteria commonly cause spoilage; Pseudomonas fluorescens, L. lactic, Klebsiella, Pantoea, and Bacillus cereus are blue molds causing spoilage

Nelson, J. 1970. Production of Blue cheese flavor via submerged fermentation by Penicillium roqueforti. J. Agric. Food Chem. (4): 567.Concepts: Submerged fermentation process; Mold cultured in sterile milk-based medium with high osmotic pressure; Enzymaticall hydrolyzed milkfat added; Allowed to ferment, then high heat added to inactivate mold

Patton S. 1950. The Methyl Ketones of Blue Cheese and their Relation to its Flavor. J.Dairy Sci. 33(9):680-4.Concepts: Fatty acids in cheese undergo beta-oxidation to form ketones associated with aroma of cheese; Methyl ketones are the constituents that give mold-ripened cheeses their distinct taste

Saint-Eve A, Lauverjat C, Magnan C, Deleris I, Souchon I. 2009. Reducing salt and fat content: Impact of composition, texture and cognitive interactions on the perception of flavoured model cheeses. Food Chem. 116(1):167-75. Concepts: Salt content effects cheese properties; Fat content effects cheese properties; Sensory properties are the result of physiochemical characteristics

Voigt DD, Chevalier F, Qian MC, Kelly AL. 2010. Effect of high-pressure treatment on microbiology, proteolysis, lipolysis and levels of flavour compounds in mature blue-veined cheese. Innovative Food Science and Emerging Technologies 11(1):68-77. Concepts: Bacterial cells sensitive to high pressure; High pressure has antimicrobial effect; Flavor compounds derived from metabolic pathways; High pressure causes lower pH; High pressure may possibly stop undesirable further ripening

Wright J. 2012. Diethyl succinate. Perfum.Flavor. 37(4):22-3. Concepts: Chemical characteristics of diethyl succinate; Deepens, enhances, and rounds out taste effects; Adds subtly to fruity taste