CA2086882A1 - Yogurt starter culture and process - Google Patents

Abstract

Abstract A yogurt culture medium of milk solids, yeast, phosphate and a minor but substantial amount of bland enzymatically digested lactalbumin improves shelf life and flavor of frozen yogurt by accentuating development of S.
thermophilus.
njl/spec/8469.djd

Description

~38~
DKt: 8469 YOGURT STARTER CULTUR~ AND P~O OE 5S

The present invention relates to a starter culture for preparing yogurt products and more particularly a milk based starter composition for yogurt cultures particularly Streptococcus thermoPhilus used to prepare frozen yogurt products.

Descri~tion of the Prior Art Kirk & Othmer, Encyclopedia of Chemical Technolo-gy, Third Edition, volume 1~, p. 564, John Wiley ~ Sons,Inc. (1981) describe ~ogurt as a fermented milk product that is rapidly increasing in consumption in the United - States. Milk is fermented with Lactobacillus bulqaricus and Streptococcus thermophilus organisms producing lactic ~cid~ us~la ~y ~ fi;~ cream or nonfat dried milk is a~ae~ to the milk in order to obtain a heavy-bodied product.
Yogurt is manufactured similarly to buttermilk.
Milk with a fat content of 1 to S% and a nonfat solids content (SNF) of 11 to 14%, is heated to about 82C and held for 30 minutes. After homogenization, the milk is cooled to 43 to 46C and inoculated with 2% culture. The product is incubated at 43C for three hours in a vat or in the final container. The yogurt is cooled and held at less than 4.4C. The cooled product should have a titratable acidity of 1.0 to 1.2% and a pH of 4.3 to 4.4. The titratable acidity is expressed in terms of percentage of lactic acid which is determined by the amount of 0Ol N
NaOH/100 mL required to neutralize the substance. Thus, 10 mL of 0.1 N NaOH/100 mL required to neutralize the sub-stance represents 0.10% acidity. Yogurts with less than 2%
Eat are popular. Fruit flavored yogurts are also common;
30 to 50 9 of fruit is placed in the carton before or with the yogurt.
W.S. Arbuckle, Ice Cream, Fourth Edition, an Avi Book, Van Nostrand Reinhold Company, l9a6, p. 3, indicates frozen yogurt is a cultured frozen product containing the n ~ n % ~ 2 same ingredients as ice cream. It contains not less than 3.25% milk fat and not less than 8.25~ nonfat milk solids and has a titratable acidity of not less than 0 .56 . The finished frozen yogurt shall weight not less than 5 lb/gal.
SLow fat frozen yogurt contains not less than 0.5%
or more than 2.0% milk fat.
Nonfat yogurt contains less than 0.5% ~at. The specifications for these products have not become sta~dard-ized.
10On page 29, Arbuckle presents a table containing in part the following information:

Approximate Comps~ition ~%) of Commercial Ice Cream and Related Products _ ProductHLLI~fat Non~t Sugar Stabilizers Approxin~te l~lk andTS
S~ nulsiEier~
20 Econ~nq ice cream 10.010.0-11.0 15.0 0.10 35.0-37.0 12.0 ~.0-10.013.0-16.0 0.20 0.40 Trade brand i~e cream 12.0 11.0 15.0 ~.30 37.5-39.0 14.0 8.0-9.013.0-16.0 0.20-0.40 DellLxe ic~ cres~ 16.0 7.0-8.0 13.0-16.0 0.20-0.~0 40.U-41.0 (prem~ upar pr~ni~) 18.0-20.0 6.0-7.516.0-17.0 0.0-0.20 ~12.0-45.0 20.0 5.0-6.014.0-17.0 0.25 ~6.0 Frozen logurt 3.25-6.08.25-13.0 15.0-17.0 0.50 30.0-33.(1 3 0 0.5-2.08.25-13.0 15.0-17.0 0.60 29.0-32.0 <0.5 8.25-14.015.0-17.0 0.60 28.(1-31.0 On page 434, Arbuckle presents standards for 35frozen yogurt. Froæen yogurt is the food prepared by freezing while stirring a pasteurized mix consisting of the same ingredients permitted for ice cream in the CFR, Title 21, Part 135 .110 . These in~redients are cultured after pasteurization by one or more strains of Lactobacillus 40bulqaricus and Streptococcus _ thermophilus, provided, however, fruit~, nuts, or other flavoring materials may be added before or after the mix is pasteurized an~ cultured.
Bacteria and coliform requirements for frozen yogurt applies to the mix before culturing. Frozen yogurt con-njl/~pec/~69.djd 8 ~

tains not less than 3.25% milkfat and not less than 8.25%
nonfat milk solids and has a titratable acidity of not less than 0.5~, expressed as lactic acid. This characteristic acidity, developed as the result of bacterial activity, is applied to the product after culturing. No heat or bacte-riostatic trea~ment (other than refrigeration), which results in the total destruction of the microorganisms, may be applied to the product after culturing. The finished yogurt weight is not less than 5 lb/gal.
Lowfat frozen yogurt is the food prepared from the same ingredients and in the same manner prescribed in the CFR for frozen yogurt. Lowfat frozen yogurt, exclusive o any flavorings, shall not contain less than 0~5 or more than 2% milkfat.
A typical formula and process is set forth by Arbuckle on page 398.

Formula (10 gal) (lb) Yogurt base or whole milk 55.0 Sugar 17.0 Stabilizer 0.2 Fruit 17.8 Total 90.0 Place whole pasteurized, homogenized milk in vat and inoculate with 1% yogurt culture; hold at 90F until set; or place milk, sugar, and stabilizer in vat, pasteur-ize and homogenize, and then inoculate and hold. Mix stabilizer with 5 times its weight of sugar and disperse carefully with good agitation. Add remainder of sweeteners and fruit and allow to mix well. Pump to freezer flavor tank. In continuous freezers use a temperature of 21F.
Freeze to 50~ overrun or 13 oz/pt. Harden at -20F in the usual manner.

ni ~ /R/~ ~n ~

Summary of the Invention The use of a reconstituted starter medium or composition containing a major a~ount of milk product solids and a milk protein nutrient having minimal flavor - 5 impact on final yogurt flavor has been found to promote the growth of Streptococcus thermophilus bacteria and to produce a frozen yogurt product which has improved product shelf life due to reduced gram negative spoilage and slow acidity development during refrigerated storage, minimal milk protein off flavor, a lack of undesirable acid flavor resulting from the usual use of L. bul~aricus and improved viscosity and water binding properties resulting from polysaccharides developed by S. thermophilus during cultur-ing.
The culture medium or composition contains a major amount of whey and nonfat dry milk, minor amounts of yeast extract and phosphate nutrients and a minor but substantial amount of a milk nutrient, preferably prepared from enzymatic treatment of lactalbumin.
The culture medium is hydrated in water, pasteur-ized, cooled and inoculated with yogurt culture, preferably containing a major amount of S. thermo~ilus and, prefera-bly not containing L. bul~aricus. This composition is cultured for up to 8 hours at pH 6Ø The cultured starter medium is next added to pasteurized yogurt base to innoculate the hase and cultured for about 6 hours in the retail package or in a vat to develop the characteristic yogurt acidity and viscosity or gel.
The enhancement of S. thermophilus growth insures a mild flavored stable acid product which is stable for a longer period of time than is obtained from normal yo~urt cultures containing S. thermo~hilus and L. bul~aricus.

Detailed Description of the Invention The culture composition of this invention com-prises a dry mixture of a major amount of milk proteins, minor amounts of yeast extract and phosphate nutrients and ~ P~/~4~q.~i~

~D8~2 a minor but substantial amount of a bland hydrolyzed milk protein amino acid containing nutrient. An amount of the culture composition is added to water, pasteurized and cooled. Yogurt culture bacteria is then added to inoculate the mixture which is cultured to develop the S.
thermophilus. The resulting starter culture is next supplemented with sufficient freeze dried L. acidophilus and L. bulqaricus to produce an initial starter culture containing 10 to 20 million S. thermo~hilus and 1 million each of L. acidophilus and L. bulqaric~s per milliliter of starter culture added to a yogurt base containing milk, sugar and optional flavorants. The starter culture is designed to enhance the growth of S. thermophilus so that resulting frozen yogurt products prepared from the starter have a longer shelf life as a result of less development of aciditv durina stor~ge, lower introduction of off flavor which often results when using hydrolyæed casein protein nutrients, and improve viscosity and mouthfeel due to generation of polysaccharides by S. thermoPhilus and greater stability against spoilage by gram negative bacte-ria. The starter culture is then used to innoculate a pasteurized yogurt base and fermented to produce the final frozen yogurt product.
we prefer to use S. thermophilus per se or optionally combined with L. acidophilus and to refrain from use of L. bulgar cus although minor amounts may be used particularly after preparing the starter culture if de-sired. Frozen yogurt does not have a standard of identity except in some states which requires the use of both S.
thermophilus and L. bulgaricus as is required for most yogurt products. This invention would work equally well making normal yogurt should the standard of identity be changed or should L bulqaricus be used as set forth previously.
In a preferred embodiment method we innoculate the culture composition with 5. to obtain a level of 10 to 20 million bacteria per milliliter after n i ~ / Q ~ r~

culturing in the starter culture. We then add sufficient freeze dried L. bul~ricus and Lo acidophilus to obtain an initial level of about l million each per milliliter of starter culture.
The dry culture medium or composition contains a major amount of milk solids and a minor but substantial amount of hydrolyzed milk protein nutrient. The composi-tion additionally contains a yeast and phosphate nutrient.
The milk solids can include sweet whey, dry milk, nonfat dry milk, cream and similar mil~ solids. We prefer to employ from 50 to 75~ milk solids, more particularly 60 to 70~ primarily sweet whey and nonfat dry milk solids.
About 2 parts sweet whey is used for each part of dry nonfat milk solids to develop the milk solids employed in our composition.
We employ up to 5%, preferably 1 to 4% yeast extract which can be obtail,ed ~rom any food approve~ edible yeast.
We employ one or more phosphates to improve the nutrient balance of our starter culture, preferably using up to 5~, preferably 1 to 4~ of disodium phosphate ( Na2PO4 ) .
Finally, we employ up to 75%, preferably from 15 to 45% and more preferably from 20 to 40% of a hydrolyzed milk protein of neutral flavor which can be prepared from casein or lactalbumin. We pre~er to use an enzymatically prepared lactalbumin, such as Dellac LE80GMX available from Deltown Chemurgic Corporation, P.O. Box 712, Fraser, New York, 13753.
Dellac LE80GMX is an enzymatic digest of lactal-bumin specifically designed for nutritional applications.
The lactalbumin is an excellent source of nutritionally balanced essential amino acids and has an exceptionally good flavor. The lactalbumin has the following character-istics:

nil /~/~4~9.~itl 2~3~

Amino Nitrogen (AN) 4.9%
Total Nitrogen (TN) 11.4%
AN/TN x 100 43.0%
Total Protein (TN x 6.38) 72.7%
Ash 4.3%
NaCl 1.3%
Moisture 5.5%
pH (6% solution) 6.8 Microblal Content Standard Plate <30,000/gm Coliform <10/gm Thermophiles <1,000/gm Yeast and Mold <100/gm Salmonella Neg/25 gm Solubility - 100 gm/liter at 25C.

The culture medium or composition is employed in a concentration of 5 to 15%, preferably 10% in waterO We use about 120 lbs. of dry culture composition for each 150 gallons of water or about 10% w/v. Obviously, more or less of the culture medium may be added to the water but we have found 10% of the formulation, which follows, gives good results.
The preferred culture medium is prepared by dry blending the following ingredients. ~lending and packaging time should be minimized to prevent moisture absarptian during blending.

DrY Culture In~redients Percenta~e in Dry Blend Grade A Sweet Whey 45.0%
Grade A Nonfat Dry Milk 20.0%
YE 2200 yeast extract - Gist Biocades 2.5%
Disodium Phosphate 2.5%
Lactalbumin - LE80GMX, Deltown Chemurgics 30.0%
Total Ingredients: 100.0%

The medium should be checked for yuality prior to use in preparing frozen yogurt. 100 grams of dry culture ingredients are mixed into one liter of water ~or a fin ished volume of 10~ (W/V). The mixture is pasteurized at 190F for 30 minutes. The pasteurized mixture is cooled to 108F and inoculated with S. thermoPhilus (DPL 610THj freeze-dried culture. The inoculated culture is maintained at a pH of 6.0 by the addition of a suitable base such as ammonium hydroxide for about 8 hours to develop the bacte-rial content of the cultuxe. 3000 gallons of pasteurizedyogurt base (18 to 19% nonfat solids) is innoculated with 7~ gallons of the starter culture ~about 2.5% W/V) and incubated at 108 to 110F for 5 to 6 hours.
The yogurt i5 cooled to 40F when the titrata~le acidity reaches 1.3 to 1.4%. The cooled yogurt is combined with the remaining yogurt ingredie~ts to make the finished product.
The nonfat solids content of the yogurt base is adjusted to from 14 to 20%, preferably 16 to 20% and most preferably 17 to 19%.
The starting pH of the starter mix will vary dependent on the flavor, but generally it will be below pH
6Ø A relatively rapid drop in pH during storage of the final product will generally prevent gram negative bacterl-2~ al spoilage, but the high acid flavor is considered unde-sirable in a frozen yogurt.
There follow several examples intended to illus-trate but no~ limit the scope o~ our invention.

n i l / ~ r / ~ i A

~xampl~ 1 A plant trial was run using a culture medium having the following formula:

Dry Culture IngredientsPercentage in Dry Blend Grade A Sweet Whey 35.0~
Yeast Extract 2.5%
Disodium Phosphate 2.S~
Lactalbumin (enzymatically digested) 60.0 Total Ingredients 100.0~

The culture medium was added to water to give 10%
solids~ 250 gallons of the mixture was pasteurized and cooled. 60 grams, freeze dried Streptococcus thermophilus was added and the mixture cultured for eight hours at a temperature of about 108Fo Liquid ammonia was added during the fermentation to malntain a pH ~etween 5.8 and 6.3. The ripened starter mixture was added at 2.5% to a pasteurized yogurt base and cultured. Freeze dried L.
acidolphilus and L. bulgaricus were each added to the .

pasteurized yogurt base at a level of 0.01 grams per liter of base. This resulted in an initial count of one million of each microorganism per milliliter of base. The S.
thermoPhilus was present at a level of approximately 10 to 20 million organisms per milliliter of base. The activity of the medium was good reaching 1.00% TA (total acidity) in four hours. The acid development plateaued at 1.06% in five hours and reached 1.17% after chilling. The fresh frozen yogurt product had flavor as good or better than yogurt made using standard cultures.

n~1 /cr~ q Ex~mple 2 Another plant trial was made using a culture medium having one half the lactalbumin replaced by skim milk solids. The culture medium had the following formula-Dry Culture_Ingredients Percenta~e in Dry Blend Grade A Sweet Whey 45.0~
Grade A Nonfat dry milk 20.0%
Yeast Extract - YG 2200 from Gist Biocades 2.5%
Disodium Phosphate 2.5%
Lactalbumin - Dellac LE80GMX 30.0~
Total Ingredients 100.0%

The culture medium was added to water to give 10%
solids. 250 gallons of the mixture was pasteurized and cooled. 60 grams freeze dried Streptococcus thermo,philus added and the mixture cultured at 108F for 8 hours at pH
6 adjusting the pH using a suitable base. 2.5% of the cultured starter was added to yogurt base as well as minor amounts of L. acidolphilus and L. bulgaricus as in Example 1 to prepare two batches of yogurt having 18% and 14.5%
SNF. The activity of the culture medi~m was somewhat less than Example 1 reaching 1.05% TA (total acidity) in 5 to 6 hours. The chilled TA of the la% SMF sample was 1.36%
versus 1.12 % in the 14.5% SNF sample. Both cultures gave finished product with excellent flavor and mouthfeel and the samples were sub]ected to shelf life studies at 40F
which are reported in Example 4.
The yogurt base is prepared from 15 to 20~ milk solids made from condensed milk.
Frozen yogurt mix was prepared by blending the ripened yogurt base with a second mixture containing stabilizers, milk solids, sugar and water. ~he yogurt portion of the base was used to 10 to 15% of the final mix for low acid flavors or at 25 to 35% for high acid frozen yogurt flavors.

n j 1/ spec / 84 69 . d i d The higher solid level gave a higher plateau for developed acidity. The plateau acidity can be adjusted as high as 1.5 or 1.6 TA by using appropriate high solids amounts. Levels of 16 to 20~ solids develop good TA.

t~

Example 3 A plant trial was made using the cul-ture medium of Example 2 to prepare a starter culture as in Example 2.
The starter culture was added to yogurt base having a 19.2%
SNF level for maximum TA development. In addition, to an initial count of 10 to 20 million per milliliter of S.
thermophilus, we added 0.01 gms per liter of L. acido~hilus and L. bulqaricus~ to provide an initial count of about 1 million per milliliter of each microorganism. The activity of the yogurt base improved to 1.20~ TA in 5.25 hours with a final TA of 1.44% after chilling. This TA would be equivalent to a TA of 1.35 to 1.4% for a nonfat solids (SNF) content of 17.5 to 18~. The finished products from this trial were indistinguishable from controls made with a regular started system containin~ both S. thermoPhilus and L. bulqaricus and the samples were subjected to shelf life studies at ~0P whic' ale ie~OL~C.' ;,I Example 4.

~ Our cultures are typically 1 x 1011 organisms per gram of freeze dried culture. We attempt to obtain an initial count in which at least 80% and preferably 90% of the microorganisms present are S. therm_~hilus.

nil /~ /R~q . li,l Example 4 Products from both Example 2 and Example 3 were stored at 40F and tasted periodically. Results are summarized on the following Tables 1 and 2. Perhaps the most significant observation from the shelf life studies was a significant improvement both in resistance to gram negative spoilage and in control of acid development in the test samples. Between the two trials, 10 or 12 samples showed no gram negative spoilage or high acid development in six weeks at 40F. Of three control samples made with the regular starter system, two displayed severe gram negative spoilage and the third had dropped so low in pH to 4.37 that it could be considered acid spoiled. (Gram negatives cannot grow below pH 4.6, but yogurt below this pH is unpalatable.) More remarkably, four of the Example 2 samples were shelf stable for 75 days. These samples were opened repeatedly for flavoring during tha~ time and showed no significant acid development, and only two were spoiled by gram negatives.
The Control Strawberry had a 6 week pH of 4.37 with a noticeable acid flavor whereas the two strawberry mixes made with the starter culture of this invention had considerably higher pH's of 5.24 and 4.86 with a good flavor. A similar benefit can be seen in comparing the Control Vanilla with the cultures of this invention. Even though the Control Chocolate had a similar 6 week pH as did the chocolate of this invention, there was a noticable flavor difference with control resulting in bacterial spoilaye.
A relatively rapid drop in pH during storage of the final product will generally prevent gram negative bacterial spoilage, but the high acid flavor is considered undesirable in a frozen yogurt.
Samples were also tested for total lactic cell counts and for L. acidophilus counts (Table 2). The general trends observed are that th~re is no significant difference between control and test samples in total lactic ni l /~ r ~

~8~2 count and in survival of that count. The data suggests that trial samples ma~ have superior survival of L. aci-dophilus.

-15~
Table 1. S~elf-life o~ Fr~zen Yogurt Mi~ Sa~ples ~eld at 40~:
FlavorExample 6 Week 6 11 11 Flavor Week Week Week pH Flavor pH
Butter Pecan 2 Good 5.88Good 5.29 Strawberry 2 Good 5.24Good 4.72 Banana 2 Good 5.90 * 5.32 Vanilla 2 Good 5.98 * 5.51 Banana 3 Good 5.41 Pistachio 3 * 4.98 Vanilla 3 Good 5.25 Macadamia 3 * 5.24 Chocolate 3 Good 5.90 Strawberry 3 Good 4.86 White Russl_n 3 G~,od 5.42 Straw Cheesecake 3 Good5.59 ~0 Control Chocolate 2 * 5~80 Control Strawberry 3 Fair4.37 Acidic Control Vanilla 3 * 4.67 ~ Off flavor resulting from gram negative bacteria caused spoilage n jl/spec/8469 . d jd Table ~. Cell Count~ of Frozen Yogurt Samples Total Count-Lactic Acid bacteria 3 Weeks 6 Weeks 6 Week~
FlavorExample at 40F at 40F at-40F
_ __ _ --Strawberry 2 NA 2.8 x 10~ NA
(11 Week) Vanilla 3 6.1 x 10~ 1.6 x 107 4.7 x 107 Chocolate 3 9.5 x 10' 5.4 x 107 NA
Strawberry 3 1.1 x 107 1.3 x 10~ 3.3 x 108 Control Vanilla 2 1.1 x 10~ NA 8.3 x 10' Macadamia 3 4.7 x 107 NA 5.4 x 107 Pistaschio 3 4.9 x 10' NA 5.2 x 10' Hard Pack 3 ~.4 x 10' NA 2.5 x 107 (3 Weeks at 40F
and 3 Weeks at -20F) Control 2 NA ~ 1.0 x I0 Hard Pack The preceding examples establish that the started culture composition of this invention:
a) Improves product shelf life at 40F due to reduced gram negative spoilage;

b) Improves or maintains high yogurt ide~tity due to minimal flavor interference by the milk protein nutrient and reduced after-acidification by the conventional L._bulgaricus culture;

c) Improves L. acidoE~ilus levels and survival due to reduced competition by L. bulgaricus;
3~
d) Improves control of acid development due to self-limiting nature of the fermentation of S
thermop_ilus; and e) Improves viscosity and water-bindlng proper-tiss of the culture through use of various levels n jl/spec/8469 . djd of polysaccharride producing S. thermophilus strains.
~ ogurt is normally not prepared using a starter medium. It is prepared by simpl~ adding the mixture of S.
~ and L. bulg~ricus (equal portions ) to milk .
The prior art has heretofor believed that the L. bulgaricus was necessary to promote the growth of S. thermo~hilus.
Starter systems were not used because they were too strong-ly f lavored being normally used in chee~e manuf acture ~
We have f ound that by using a f lavor neutral hydrolyzed milk protein, preferably enzymatically dige~ted lactalbumin, we are able to culture yogurt using only S~
thermoPhilus or optionally combining with L. ac do~kilus.
~o L. bulq~ricuæ is used which prevents generation of acid during refrigerated storage. In addition, the composition and process of this invention are effective, for some unknown reason, is reducing the amount of gram neg~ L.i~e bacterial spoilage of finished product.

n~l/spe~/8469.djd

Claims (10)

1. A culture composition comprising 50 to 75%
milk solids, up to 5% phosphate, up to 5% yeast and 15 to 65% enzymatically treated milk protein nutrient having a bland flavor.

2. The composition of Claim 1 comprising 60 to 70% of a mixture of sweet whey and nonfat milk, 1 to 4%
disodium phosphate, 1 to 4% yeast extract and 20 to 40%
enzymatically treated lactalbumin.

3. The composition of Claim 1 consisting essen-tially of about 45% sweet whey, about 20% nonfat dry milk, about 2.5% yeast extract, about 2.5% disodium phosphate and about 30% enzymatically treated lactalbumin.

4. The method of preparing yogurt comprising:
a) adding a dry mix of 50 to 75% milk solids selected from the group con-sisting of whey, nonfat milk and mix-tures thereof and 15 to 45% enzymati-cally treated milk protein to water;
b) pasteurizing the resulting mix-ture;
c) cooling the mixture;
d) introducing a yogurt bacteria cul-ture not containing L. bulgaricus to the mixture;
e) culturing the mixture for a period of time effective to develop a yogurt starter;
f) inoculating a yogurt base with yogurt starter; and g) culturing the mixture to develop a yogurt having an improved shelf life when the resulting yogurt product is stored in a frozen condition.

njl/spec/8469.djd

5. The method of Claim 4 in which the yogurt is frozen yogurt and the dry mix contains 60 to 70% milk solids, 1 to 4% yeast, 1 to 4% phosphate and 20 to 40%
lactalbumin.

6. The method of Claim 5 in which the pasteur-ized mixture is inoculated with S. thermophilus and cul-tured for at least four hours to a pH below 6Ø

7. The method wherein the cultured mixture of Claim 6 is added to a yogurt base along with L. acidophilus and L. bulgaricus such that at least 80% of the microorgan-isms initially added to the yogurt base are S.
thermophilus.

8. The method of Claim 6 in which the nonfat solids content of the yogurt base is from 16 to 20%.

9. The method of Claim 8 in which the dry mix comprises about 45% sweet whey, about 20% dry milk solids, about 2.5% yeast extract, about 2.5% disodium phosphate and about 30% enzymatically treated lactalbumin.

10. The method of improving the shelf life of frozen yogurt against gram negative bacteria and acidity comprising culturing the yogurt with a starter prepared using a bacteria inoculant of S. thermophilus which does not contain L. bulgaricus and a culture medium containing enzymatically treated milk protein.
njl/spec/8469.djd