FAT RICH DAIRY PRODUCTS

Module 5. Quality and preservation of cream

Lesson 15
GRADING OF CREAM

15.1 Introduction

The purchase of inferior cream at top prices, arising from very keen competition and bitter antagonism amongst buyers, One creamery would rigidly enforce measures towards keeping up the standards of quality of their product, by paying for cream according to purity and the fat content, while other creameries, regardless of reputations, added to their patrons by buying at the highest price irrespective of its quality.

Purpose

The grading of the daily receipts of cream at the factory has a two-fold purpose, namely:

1. Each can of raw material is or should be graded for purpose of enabling the creamery to pay for it on the basis its quality, and to reject deliveries that are unfit for butter manufacture.

2. Grading is essential also in order to enable the operator to group the cream according to quality into such grades manufacture, as will best suit the market requirements of different grades of butter.

The manufacture of butter of superior quality depends, primarily, on good milk or cream. The quality of the raw material is the foundation of the quality of the finished product. The only permanently successful monitor for the creamery to insure a supply of milk and cream of quality is that of grading every can of raw material received and paying for it according to its quality. This will make the market for a product of good quality attractive and profitable to the producer, and it will make his market for a product of inferior quality unattractive and unprofitable.

Practice of Grading Cream: With hand-separated cream the first duty of the grader is to get the cans methodically, and to test each one for aroma and smell, which can be done most effectively immediately after the lids are removed. It should, therefore, be an understood order in creamery management that no person but the grader should take the lids off the vessels. With a taint in cream, and if volatile, as most are particularly in warm weather, the air space over the cream will be charged with gases, and these will be instantly liberated on the opening of the cans. The next duty of the grader is to examine for flavor and taste.

15.2 Judging of Cream

Flavor: In testing samples the use of the finger is permissible, and as soon as the examination is over, the finger should be cleansed. As the work entails considerable strain on the palate, it is unwise to swallow even small quantities of choice cream. To facilitate accurate results of different samples it is suggested that the grader should wash the mouth at intervals with warm water. The use of the finger may be queried. To detect the smell of the cream, the sample should be properly stirred. The cans which give evidence of staleness may be classed as unfit to mix with a first-rate product. After grading, the cream passes through the straining process and is then pasteurized separately.

Body and Texture: The cream should show an even consistency, firm in body with a velvety surface. When poured from one vessel to another, faint granular appearance should be noticed. There should be no clots or lumps in the cream. Condition frequently arising from the mixing of warm and cold supplies, which vary in density, and the presence of churned or half-churned granules of butter show a faulty condition. The cream should also be free from ropiness or sliminess arising from contamination with bacteria of diseased udders, or from cows long in milk, inferior herbage, or it may be from cleaning separators in strong alkaline solutions, and not washing away all traces of the soap.

Colour: The cream should be free of whiteness caused by poor food, and breed of cows; freedom from red streaks or a yellow colour indicative of diseased udders, colostrum or injurious bacterial changes.

15.3 Table Cream

A. Score card for judging cream is same as for Market Milk

B. Procedure of examination

a) Sampling
b) Sequence of observations. Carefully transfer bottle/container from refrigerator/cold room (5-10°C/40-50°F) to the laboratory in a vertical position, avoiding undue agitation. Then examine in the following order:

i. take note of serum separation;

ii. take note of sediment at the bottom of the bottle;

iii. observe container and closure for fullness, cleanliness and general appearance;

iv. take note of cream plug, if any;

v. secure representative sample for bacterial count (aseptically by standard procedures), to be used later for other tests;

vi. temper cream to l0°C (50°F) and determine viscosity;

vii. Take about 20 ml cream in a 100 ml beaker. Warm it to 15-21°C (60-70°F) and note the smell. Then put some cream in the mouth and note the taste;

viii. determine percentage of titratable acidity and fat;

ix. Test for defects such as oiling-off, feathering in coffee, etc.

Requirements of high-grade table cream: High quality table cream should have a clean, sweet, pleasant, nutty flavor. The body should be smooth, uniform and reasonably viscous for the percentage of fat present. The physical appearance should be good.

15.4 Classification of Cream Grades

A. Special or Sweet Cream Grade: Cream that is clean, fresh, sweet and free from any off- flavor ,free from any visible or objectionable extraneous matter; and the acidity of which has at no time exceeded 0.2% , calculated as lactic acid.

B. First Grade Cream: Cream that is clean in flavor, free from off-flavors and from objectionable extraneous matter; and the acidity of which has at no time exceeded0.6%, calculated as lactic acid.

C. Second Grade Cream: Cream may have acidity in excess of 0.6%. It may contain objectionable flavors and odors to a moderate degree, such as slightly cheesy, slightly rancid, slightly tallowy, slightly metallic, slightly bitter, slightly yeasty, etc. It must be free from the flavor and odor of obnoxious weeds, such as onion, garlic, leek, French weed, peppergrass, etc.; from the flavor or odor of gasoline, kerosene, machine oil, or other foreign oil; from contamination with dirt, filth and other objectionable extraneous matter; and from mold and products of putrefaction.

D. Weed Flavored Cream Grade: To this grade belongs all cream suitable to be classed with any of the previous grades, but that is infested with the flavor of obnoxious weeds, such as onion, garlic, and leek. French weed, certain weeds associated with peppergrass, etc.

E. Illegal Cream: This includes all cream that fails to meet the requirements of any of the previous grades. It is cream that contains the flavor of gasoline, kerosene, machine oil, or other foreign oil; or that is so deteriorated as to have a pronounced cheesy, rancid or metallic flavor; or that is contaminated with products of putrefaction, or dirt, or filth or other objectionable foreign matter that renders it unfit for human consumption.

15.4.1 Uses of Cream

i. For direct consumption as table/coffee/whipping creams.

ii. In the preparation of special dishes.

iii. In the production of plastic, frozen and cultured (sour) creams.

iv. In the manufacture of butter, cream, cheese, ice cream, butteroil and ghee(India).

v. For creaming cottage cheese.

vi. Dried cream is used for dried fruits, dried soups, cake mixes desert makings, Ice cream mixes etc.