Document Type

Thesis - Open Access

Award Date

1984

Degree Name

Master of Science (MS)

Department / School

Dairy Science

First Advisor

Kenneth R. Spurgeon

Abstract

The United States (US) cheese industry has grown rapidly in the past decade. From 1971 to 1981, milk fat utilization for cheese manufacture increased from 17.7 to 27.6% of the total US milk fat supply, accompanied by a 49% increase in sales of cheese per capita (34). Offsetting substantial increases in sales and prices for cheeses, there have been marked increases in the cost of labor, energy, waste treatment, raw materials, and equipment. Hence, the manufacturers are realizing narrower profit margins. As a survival mechanism, cheesemakers have sought to maximize cheese yields per unit of milk, since increases in cheese yields logically would lead to increased profits. Actually, however, cheesemakers have observed decreases in product yields during the past 20 to 30 yr. This decrease is primarily due to milk producers breeding and feeding for higher milk production, as there is an inverse relationship between volume of milk produced and solids content (60). From 1971 to 1981, annual milk production per cow in the US increased from 4423 to 5510 kg (9,751 to 12,147 lb), accompanied by a decrease in solids. It follows that solids content will continue to decrease as milk production per cow increases (16). Obviously, there is a direct relationship between milk solids content and cheese yields per 100 kg of milk. Research abroad has indicated cheese yields can be increased by vacuum concentrating milk prior to cheesemaking (26). Vacuum concentration is the process by which milk is heated to boiling under a vacuum and water removed as water vapor. Boiling is .achieved at a lower temperature due to the reduced pressure on the milk under vacuum. This lower temperature treatment causes less protein degradation than would occur by boiling off the water at normal atmospheric pressure and resultant higher temperature. Other researchers have found vacuum concentration resulted in greater retention of milk fat in cheese (25). The process can also lead to increased productivity, since more cheese can be produced in the same equipment without an increase in labor. Whey processing costs are also decreased, as there is less whey volume from concentrated milks that are made into cheese compared to the whey from unconcentrated milk made into cheese. Increasingly important, with motor fuel prices on the increase, is the economic advantage of concentrating milk before shipping over long distances (5). Hauling costs are reduced since a tanker carries more solids per load, with less money spent to transport water. Although there are reports (11, 21) of preconcentration of milk by ultrafiltration for cheesemaking in the US, few research reports were found on vacuum concentration for this purpose. Ultrafiltration equipment tends to be large, requiring more floor space than vacuum concentration equipment. Ultrafiltration equipment is also limited in its capacity, in relation to that of vacuum concentration. Moreover, many dairy plants already have vacuum concentration equipment. Too, although ultrafiltration is legal for the manufacture of processed cheese, it is currently not legal for cheddar cheese manufacture. Hence, with indications of increased cheese yields and greater productivity, it seemed practical to investigate the potentials of vacuum concentration of milk for cheesemaking, primarily cheddar cheese manufacture, while also determining whether the resultant cheese was comparable or superior to cheese as normally made from fluid milk.

Library of Congress Subject Headings

Cheddar cheese

Description

Includes bibliographical references (pages 57-61)

Format

application/pdf

Number of Pages

77

Publisher

South Dakota State University

Rights

In Copyright - Non-Commercial Use Permitted
http://rightsstatements.org/vocab/InC-NC/1.0/

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Dairy Science Commons

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