Recipient Organization
MICHIGAN STATE UNIV
(N/A)
EAST LANSING,MI 48824
Performing Department
Food Science
Non Technical Summary
Milk and dairy foods is an important part of the US diet as well of those around the world. All throughout history milk has had a wholesome and a 'natural' image, and the U.S. standards of identity for dairy products have maintained this image. Milk and dairy foods are a good and cost effective source of high quality protein, vitamin A, D, riboflavin and folate, and minerals: calcium, phosphorus, magnesium and potassium. There is also increasing scientific information that shows importance of dairy foods in bone health, weight management, managing Type 2 diabetes, and high blood pressure (Miller et al., 2007). Thus, for many years milk and dairy foods have also been an important component of federal programs. The dairy industry is one of the oldest agricultural industries worldwide, and in Michigan, it is one of the largest. The dairy industry plays a significant role in the economy of the United States ranking third in value among all U.S. agricultural commodities. Michigan is an important milk producing state. In 2015, Michigan ranked 6th in milk production in the U.S. In recent years, a number of large dairy processors such as Continental Dairy, Fairlife milk have relocated in Michigan. Today, the dairy industry contributes approximately $ 14.7 billion to the state's economy; which makes up about 20% of state's food and agricultural industry. Consumers in the U.S. spend approximately 13 percent of their food budget on milk and dairy products. Therefore, maintenance and expansion of markets for milk and dairy products are not only important because of their nutritional contribution to the U.S. diet but are also vital to the economy of Michigan and the U.S. In order for the dairy industry to remain competitive in the global market place, it is important that a new emphasis be placed on the development of value-added dairy products that are safe and identifying markets where these products fit best. This should benefit the dairy industry of Michigan. Today, worldwide forces that shape the perception of high-value include nutrition and health, safety of the food supply and concerns about the environment. Dairy foods include a wide range of products and the unique functional properties of milk components make them ideal ingredients for other foods. The potential for the development of dairy and dairy-based products with high value that is safe is unlimited. This research will focus on the processing, properties, quality and safety of these products. With a focus on for the next five years on the following: 1) Fortification of dairy foods 2) Verifying adequate pasteurization of milk in the presence of common added ingredients initially in the production of flavored milk.
Animal Health Component
70%
Research Effort Categories
Basic
(N/A)
Applied
70%
Developmental
30%
Goals / Objectives
Objective 1: Compare quality and nutritional value of iron fortified dairy foods, determine the effect of different iron salts on cheese qualityObjective 2: Determine the effect of flavor ingredients on alkaline phosphatase assay, to gain a mechanistic understanding for false positive or negative tests in the presence of these ingredients
Project Methods
Objective 1: Compare quality and nutritional value of iron fortified dairy foods.Starter culture growth and activity -Reconstituted skim milk (12%) containing iron salts (Barrington Nutritionals, Harrison, NY,) will be sterilized (121°C, 5 min). Zinc or iron salt will be omitted in the control treatments. Each flask will be cooled to 35oC and inoculated with 1% w/w commercial Cheddar cheese culture, Lactococcus lactis subsp. lactis, Lactococcus lactis subsp. cremoris, (DVS 2003, Chris Hansen, Miwaukee, WI) and incubated at 35°C for 6 h. Growth of lactic acid bacteria will be determined by sampling at one hour intervals and plating on MRS agar (Sigma-Aldrich). Plates were incubated at 35oC, 48h under aerobic conditions. Titratable acidity (TA) and pH were monitored at 30 min intervals.Cheddar cheese manufacturing -Cheddar cheese will be manufactured at Michigan State University Dairy Plant. Raw cow milk will be HTST pasteurized (72oC, 16 s). The milk will be cooled to 32oC and will be divided into two vats containing 115 kg of milk each. One vat will have the different iron salts (Barrington Nutritionals, Harrison, NY) added; the control vat will have no salts added. One percent starter culture (DVS 2003, Chris. Hansen, Milwaukee, WI) will be added to each vat while stirring. Both vats will be incubated at 32oC for 30 min. Next annatto coloring (4 mL) will be added to each vat and stirred, and 7 mL of rennet (Chy-max Chris Hansen) diluted (40X with water) will be added and stirred. Vats will be allowed to coagulate (30 min). When adequate firmness is reached, the curd will be cut using wire knives. The cut curd will be allowed to heal and slowly cooked to 38oC. End of cooking, whey will be drained, the curd will be matted, and cut into rectangular blocks and flipped every 15 min. Titratable acidity (TA) will be monitored during the cheddaring process. The curd will be milled when the TA of the curds reached 0.62 %. The milled curd will be salted (0.25%). Salted curd will be transferred into cheesecloth lined cheese hoops and pressed overnight at 40 psi. Following analysis will be conducted on the cheeses:1. Compositional analysis2. Iron analysis3. Thiobarbituric acid assay-4. Texture (hardness) analysis5.Sensory analysis by consumer panelObjective 2: Determine the effect of flavor ingredients on alkaline phosphatase assaySample preparation - The main objective of this study is to determine the effects of milk flavoring constituents (cocoa, sugar, and vanilla extract, eggnog spices) on the fluorometric assay for bovine ALP. Raw milk will be received by the MSU Dairy Plant. Raw milk will be warmed to 38oC and separated into skim milk and cream portions using a standard milk separator operating at 6000 rpm. Fat content of the skimmilk and cream portion will be determined using Babcock procedure (Wehr and Frank, 2004). Milk will then be standardized to 3.25% fat, (this is fat content of standardized whole milk) and fat content will be confirmed by Babcock procedure. After standardization, the milk will be divided into portions. Vanilla extract, cocoa powder, eggnog spices, and sugar will be added individually to each portion. Control will not contain any added ingredients. Each portion will be separately homogenized at 2,000 psi (dual-stage) using a milk homogenizer. Next, each portion will be divided into two halves. One half portion will be High Temperature Short Time (HTST) (72oC, 15 sec) pasteurized and the other half will be Low Temperature Long Time (LTLT) (63oC, 30 min) pasteurized. Both conditions are legal pasteurization conditions approved for legal pasteurization of commercial products. Each treatment (vanilla extract, cocoa, eggnog spices, sugar, and control) will be analyzed using the Fluorophos® ALP test in duplicate. All experiments will be independently replicated 3 times.Fluormetric determination of alkaline phosphatase (ALP) - Fluorometric procedure for bovine milk ALP will be conducted as described by Wehr and Frank (2004). Once the samples are prepared and the instrument is calibrated 75 µL of sample is added to the 2.0 of working Fluorphos substrate (Advanced Instruments, MA), the mixture is placed in a cuvette and place in the fluorometer. After 1 min rate of increase in fluorescence is measured (F/min) over 1- 2 min (mU/L of ALP is displayed by the instrument). Preparation of negative control: Heat milk sample to 95oC, once the targeted temperature is reached hold for 1 min. Cool rapidly to room temperature and test for ALP activity. ALP activity should be less than 10 mU/L.Preparation of positive control: Add 0.1 mL of fresh raw milk to 50 mL of negative control. Mix flask gently and add more negative control to reach 100 mL. This positive control contains 0.1 % raw milk and should test 350-500 mU/L ALP.Overall aim of our research is to determine occurrence of false positives and/or false negative in the presence of these ingredients, and combination of these ingredients. To further, gain a mechanistic understanding of the nature and chemistry of these ingredients that contribute to false positives and false negatives. Due to increased precautions regarding food safety and regulatory changes narrowing and specifying the upper limits of ALP for flavored milks will help to allow industry professionals continue the use the rapid and inexpensive ALP testing without further scrutiny and refrain from having to engage in costly and time consuming pathogen testing for ensuring product safety. Understating common ingredient interactions with widely accepted and utilized fluorometric ALP procedure in the dairy industry is the first step in narrowing and specifying food safety regulations and saving time and costs in production facilities.