Pasteurized
processed cheese products (PCPs) are cheese-based foods produced by
comminuting, blending and melting one or more natural cheeses and optional ingredients
into a smooth homogeneous blend with the aid of heat, mechanical shear and
(usually) emulsifying salts (ES). Optional ingredients which are determined by the
product type, include dairy ingredients, vegetables, meats, stabilizers,
emulsifying salts, flavours, colours, preservatives and water (Table ).
Attempts to
increase the shelf life of cheese during the early twentieth century were inspired
by the possibility of increased cheese trade, via the production of more stable
transportable products, and by the existence of heated cheese dishes such as Swiss
fondue and Kochkase. Many of the early approaches were unsuccessful, as the
heat treated cheese were unstable, as reflected by oiling off and moisture
exudation during cooling and storage. In 1911, the Swiss workers Gerber and
Stettler produced a stable, heat-treated stable Emmental cheese, known as
Schachtelkase, by the addition of a ‘melting salt’, sodium citrate, to the
commuted cheese before processing (i.e. heating and shearing). Subsequently it
was found that other cheeses (e.g. Cheddar) could also be processed to form
stable products by the addition of other ‘melting salts’ (e.g. sodium
phosphates) or blends of different emulsifying salts. The ‘melting salts’ were
gradually referred to as emulsifying salts when their functions became known,
i. e. mediation of the processes of protein hydration and emulsification of
free fat during processing. Initial successes were followed by numerous patents
for different melting salt blends and later for inclusion of food ingredients
other than cheese.
The basic aim of
processing is to blend natural cheese, water, optional ingredients and
emulsifying salts and to pasteurize the mixture to obtain an end product which has
sufficient fluidity for convenient packaging and which possesses long keeping qualities.
It is believed that the popularity of processed cheese products is based on its
uniformity, mildness and good keeping quality.
In the year 2003,
global production of PCPs is estimated at~1.5-1.8 MT per year,equal to ~ 10-12%
of natural cheese production. Moreover, production has been steadily increasing
at a rate comparable to that of natural cheese; indeed, the mean annual growth
rate (1.4%) in the 15 countries of the EU for the period 1995-99 was greater
than that (0.6%) for natural cheese. Factors contributing to the continued growth
of the PCPs include:
- the application of heat during processing stabilizes the cheese system into a physico-chemically and bacteriologically stable state enhancing the shelf life of the product. This ensures conservation of precious milk solids during glut period into a valuable form of process cheese. This product can be stored for months or even years.
- their versatility as foods that offer wide variety in flavour, texture (e.g. elasticity, firmness, spreadability, sliceability), cooking attributes (e.g. degrees of flowability, browning, viscosity), size and shape of final product, and overall consumer appeal as made possible by differences in formulation and processing conditions, condiment addition and packaging technology.their convenience of use in the food service sector, especially the fast food trade, and the home because of their excellent (stability) preservation, consistent tailormade
- functionality (e.g. flowability), convenient portion size and packaging (e.g. as slices for the beef burger and sandwiches trade)
- their popularity with children of different ages owing to their safe ingestable consistency (for infants) and mild flavours, and their packaging (colour, caricatures, strength, ease of opening, size) and shape (e.g. triangles, fingers,cartoon characters).
- their nutritive value (e.g. as a source of calcium and protein) as a food for children. Because of its digestibility and beneficial properties processed cheese is suitable as a diet food.
- their relatively low cost compared to most natural cheeses, made possible by the use of relatively cheap non-cheese solids (e.g. whey, skim milk powder),lower-grade natural cheese, and offcuts.
- Manufacture of process cheese with the addition of other food types (meat,sea-foods, mushrooms, vegetables, fruits, fruit juices, dietetic substances and vitamins.
- Manufacture of dried cheese from plain or seasoned processed cheese to be used for sprinkling on soups, pasta or to be reconverted into spread by the addition of water.
- Manufacture of dried cheese from plain or seasoned processed cheese for the preparation of bakery goods, e.g. cheese flavoured biscuits.
- developments in manufacturing technology, emulsifying salt blends and functional dairy ingredients which facilitate the manufacture of consistent quality products with customized attributes.
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