Something I found today;
Common Cheese Defects
* Body. In the context of modern sensory analysis body refers to texture, which is confusing because cheese graders use the term ‘texture’ to refer to cheese openness. Here, we will use the traditional cheese grading terms. Some descriptors for body defects are:
o Crumbly/short: often due to excess salt or acid
o Corky: due to overcooking, low fat, low moisture, or excess salt.
o Mealy: this defect can be detected on the palate or by massaging the cheese between the thumb and forefinger. It is usually associated with excess acidity.
o Pasty: sticks to the palate and fingers; due to excess moisture.
o Weak: breaks down too quickly when worked by hand; due excess fat or moisture.
# Texture relates to openness in the cheese which may or may not be desirable depending on the type of cheese and the cause of openness. Openness can be due to:
* Mechanical openings which are holes of irregular shape caused by trapped whey. Trapped whey makes the impression in the cheese during pressing, but during ripening the moisture is dispersed through out the cheese leaving the hole behind. Openness is desirable in Colby, but is considered a defect in Cheddar. Mechanical openings can lead to discolouration around the opening due to local acid development. Usually mechanical openings are closed by vacuum packaging.
* Gas holes are, of course, desirable in many types of cheese. Gas hole defects include:
o Early gas defects due to coliforms. These appear as small, sphericle, shiny holes. The defect is often associated with unclean flavour.
o Late gas due to Clostridium. tyrobutryricum or perfringens, especially in some European made cheese. Clostridia spores are often present in American cheese as well but do not normally cause problems. However, they may be activated by the heat treatment and, therefore, sometimes cause gas defect in processed cheese.
o A third gas defect occurs in Cheddar and American types. The defect is distinctive in that the gas (mainly C02 with some hydrogen sulfide) blows the package but not the cheese. The defect occurs at 6 - 9 months in Cheddar but a similar defect is sometimes observed earlier in American Mozzarella and Colby. The causative anaerobic organism is not fully identified, however, experiments have demonstrated that the defect does not occur in cheese aged at < 10C.
o Yeast slits due to yeast growth.
* Flavour. Most grading systems assign the greatest weight to flavour defects. A few common descriptors are:
o Acid flavour is often associated with acid body defects noted above. The common causes all relate to process control:
+ Too much moisture (i.e., too much lactose).
+ Too much starter (i.e., too much acid development before dipping).
+ Salting too late or too little.
+ Too warm during or immediately after pressing.
o Bitter flavours are common defects in American but also other cheese, including fresh cheese. Some causes include:
# High moisture
# Excess rennet
# Bitter cultures
# High ripening temperatures
+ Fruity/Yeasty flavours are usually associated with high pH and bitterness, and sometimes with yeast slits.
+ Unclean flavours are reminiscent of the barn yard, and may be associated with coliforms.
+ Whey taint is due to high moisture and is usually associated with acid defects including bitterness.