|Infobox on Cheese|
|Example of Cheese|
|Stowage factor (in m3/t)|
|Humidity / moisture||Cheese requires particular temperature (see text), humidity/moisture and ventilation conditions.|
|Ventilation||Recommended ventilation conditions: circulating air, 15 - 20 circulations/hour; fresh air where required. Inadequately ventilated cheese very rapidly succumbs to the risk of mold growth. In addition, drafts may cause losses in quality.|
|Risk factors||Cheese is sensitive to pressure and impact loads. Improper handling or stowage may result in damage.|
Cheese consists of proteins and fat from milk, usually the milk of cows, buffalo, goats, or sheep. It is produced by coagulation of the milk protein casein. Typically, the milk is acidified and addition of the enzyme rennet causes coagulation. The solids are separated and pressed into final form. Some cheeses have moulds on the rind or throughout. Most cheeses melt at cooking temperature. Hundreds of types of cheese are produced. Their styles, textures and flavors depend on the origin of the milk (including the animal's diet), whether they have been pasteurized, the butterfat content, the bacteria and mould, the processing, and aging. Herbs, spices, or wood smoke may be used as flavoring agents. The yellow to red color of many cheeses is from adding annatto.
For a few cheeses, the milk is curdled by adding acids such as vinegar or lemon juice. Most cheeses are acidified to a lesser degree by bacteria, which turn milk sugars into lactic acid, then the addition of rennet completes the curdling. Vegetarian alternatives to rennet are available; most are produced by fermentation of the fungus Mucor miehei, but others have been extracted from various species of the Cynara thistle family. Cheese is valued for its portability, long life, and high content of fat, protein, calcium, and phosphorus. Cheese is more compact and has a longer shelf life than milk. Cheesemakers near a dairy region may benefit from fresher, lower-priced milk, and lower shipping costs. The long storage life of some cheese, especially if it is encased in a protective rind, allows selling when markets are favorable.
Cheese contains less water than milk. The amount of water in cheese greatly influences the storage life, and its sensoric properties. Many types of cheese are stored for a certain period, known as the ripening period, which may last for weeks or months. During ripening the cheese acquires special organoleptic qualities (appearance, texture, flavour). Microorganisms play an essential role in the development of these characteristics. After ripening (at a temperature between 8°C and 25°C for many types of cheese), the cheese should be kept at a temperature between 0°C and the ripening temperature, depending on how long time it is stored.
Fresh cheeses have a high water content and should be kept at chill temperatures.
Processed cheese is made from traditional cheese and emulsifying salts, often with the addition of milk, more salt, preservatives, and food coloring. It is inexpensive, consistent, and melts smoothly. It is sold packaged and either pre-sliced or unsliced, in a number of varieties. It is also available in aerosol cans in some countries.
Categorizing cheeses by firmness is a common but inexact practice. The lines between "soft", "semi-soft", "semi-hard", and "hard" are arbitrary, and many types of cheese are made in softer or firmer variations. The main factor that controls cheese hardness is moisture content, which depends largely on the pressure with which it is packed into molds, and on aging time.
The main factor in the categorization of fresh, whey and stretched curd cheeses is their age. Fresh cheeses without additional preservatives can spoil in a matter of days.
Some cheeses are categorized by the source of the milk used to produce them or by the added fat content of the milk from which they are produced. While most of the world's commercially available cheese is made from cows' milk, many parts of the world also produce cheese from goats and sheep. Double cream cheeses are soft cheeses of cows' milk enriched with cream so that their fat content is 60% or, in the case of triple creams, 75%.
There are at least three main categories of cheese in which the presence of mold is a significant feature: soft ripened cheeses, washed rind cheeses and blue cheeses.
Cheese is a very resourceful foodstuff.
Storage and Transport
Cheese must be carried in well ventilated spaces, and on longer tropical voyages, in cool storage. Cheese should not be loaded in too fresh or too old a state. Inadequate ventilation will lead to mould formation. Ventilation must be controlled as draughts can also prove damaging. Over-stow by heavy goods may lead to pressure damage, causing spoilage. Temperatures of over 12°C for an extended period will cause most types of cheese to become over-ripe, with risk of complete spoilage. Cheeses vary as to their sensitivity to warmth. Some types when subjected to heat may double or treble their volume, burst their packing and decompose. At temperatures below 0°C cheese will dry out and harden. Cheeses are subject to loss in weight, especially if improperly stored over a long period. Depending on type, the loss may be as much as 5%. Cheese is very sensitive to odours and should be stored or stowed away from odorous goods. Any break in the packing may cause mould growth or allow the cheese to dry and crack. Mould found on some cheese may be superficial only and can often be wiped off and will not recur under proper stowage conditions. Internally the cheese should be sound and in a perfectly edible condition. Soft cheese should not be kept for over ten days. Other types of cheese may be kept for months at temperatures of 1°C / 4°C.
As to maximum duration of storage and/or recommended storage temperatures, no general guidelines can be given due to the significant range of cheese varieties. However, some rough estimates are:
- Cheddar: 0°C (several months)
- Gouda: 0°/1°C (4 months)
- Roquefort: 1°/4°C (4 weeks)
- Camembert: 2°C (6-8 weeks)
- Cheese, vacuum packed: 2°/4°C (approx. 6 months)
- Fresh cheese: 5°C (2-4 weeks)
- Emmental: 10°/12°C (several months)
If cheese is stored too cold, its quality is adversely affected by drying-out, hardening, loss of aroma (ripening halts) and spoilage. Too high temperatures initiate fermentation processes and resultant volume expansion and decomposure. Temperature variations can cause the cheese to become crumbly.
Humidity / Moisture
Generally, the harder the cheese, the less water it contains. Extraneous moisture affection is manifested by particular mold patterns.
- Mechanical influences
- Toxicity / Hazards to health
- Shrinkage / Shortage
- Insect infestation / Diseases