A cost analysis of encapsulated spray-dried milk fat.

Anhydrous butter oil or cream was encapsulated in all-purpose flour, modified cornstarch, or sucrose and then spray-dried. We estimated the processing cost for a plant designed to produce 57,000 kg/d (125,000 lbs/ d) of encapsulated milk fat powder. Powder with a 50% milk fat content could be produced for about $0.23/kg plus the cost of the butter oil or cream, the encapsulant selected, and the other ingredients. Spray-drying of milk fat improved ease of handling and reduced storage costs.

Milk pasteurisation and safety: a brief history and update.

A brief history of the development of milk pasteurisation is presented and updated. Concerns about the margin of safety provided by current pasteurisation standards in terms of milk-borne pathogens such as mycobacteria (in particular Mycobacterium paratuberculosis) and other emerging pathogens such as Listeria monocytogenes and Escherichia coli O157:H7 are discussed. With the exception of the endospores of Bacillus cereus, current standards appear to be adequate for public health assurance of milk safety provided good manufacturing practices are followed.

Thermal Destruction of Listeria monocytogenes in Ice Cream Mix.

Thermal destruction of Listeria monocytogenes strain Scott A was studied in refrigerated ice cream mixes to evaluate the relationship of mix composition to heat resistance with differing heat treatments. A central composite response surface design with two independent variables (high fructose corn syrup solids content and milkfat content) and one dependent variable (viscosity of the mix) was developed. High fructose corn syrup solids (HFCSS) content ranged from 1 to 7%, milkfat (MF) content from 4 to 18%, and total solids content from 28 to 44%. Sucrose content (11%) and milk-solids-not-fat content (10%) were kept constant. D140°F values were established in the mixes with a simulated batch pasteurization procedure using closed vials. Survivor data indicated sigmoidal responses with initial shoulders and tailing, but shoulder values were not significantly affected by either HFCSS or MF. D and F (F = 7D + shoulder) values were significantly (p = 0.01, R2 = .88; p = 0.01, R2 = .89, respectively) correlated to HCFSS content with increasing heat resistance conferred at higher concentrations. MF content had little or no effect on thermal death time but had a greater effect on viscosity of the mix than did content of HFCSS. Increased thermal resistance of LM was associated with the common ice cream stabilizer used; stabilizer contained guar gum and carrageenan. Pasteurization guidelines for ice cream mix are adequate to ensure inactivation of LM. Since results suggest that major ingredients in ice cream, ice milk, and shake mixes increase thermal resistance of LM, it is important that every precaution be taken to inactivate the organism.

Effect of Storage of Raw and Pasteurized Goats' Milk on Flavor Acceptability, Psychrotrophic Bacterial Count, and Content of Organic Acids.

Pasteurization of raw goats' milk either at 63°C for 30 min or 72°C for 15 s within 1 d of milking ensures a better tasting product both initially and during storage at 4.5°C for 6 weeks than if the raw milk is aged for several days at 4.5°C before being pasteurized. Pasteurized milks processed from high-count raw milks aged 1 to 2 weeks had lower acceptability ratings (on a 9-point hedonic scale), which decreased further in cold storage and were independent of bacterial increases in the log phase of growth. Pasteurized milks processed from raw milk 7 or more days old were subject to rapid increases in bacterial numbers in storage if they were trace-contaminated during pasteurization even though initial counts were <100 psychrotrophs/ml. For all raw and pasteurized milks, three peaks were consistently observed from an HPLC analysis designed to monitor some organic acids. Two of the components decreased and the third appeared and increased during storage. Disappearance of one component coincided with appearance of another. These compounds may be associated with loss of flavor quality of the milk since in some instances these changes significantly correlated with the decrease in hedonic ratings of the stored milks.

Fortification of soft drinks with protein from cottage cheese whey.

Cottage cheese whey protein concentrates, prepared by preconcentration by ultrafiltration followed by gel permeation to remove low molecular weight materials, have the solubility, stability and flavor that make them suitable for fortification of soft drinks and related products. These concentrates are characterized by high levels of "available" lysine and by amino acid compositions indicating good nutritional value. Carbonated beverages prepared with conventional beverage ingredients and containing up to 1% by weight of the total beverage of added whey protein maintained clarity, color, and flavor during 203 days storage at room temperature. Spray dried whey protein concentrates were incorporated without adverse effects into commercial "ade" type powders. Clarity of 1% protein solutions at pH 2--3.5 was not impaired by heating for 6h at 80 degree, but some structural change occurred since an average of 37% of the protein precipitated on shifting pH to 4.7. Increased stability against heat denaturation under acidic conditions was conferred by some soft drink ingredients. Added sucrose reduced protein denaturation by 1/2 but sodium saccharin had no effect. The type of acid used also altered protein denaturation rate. While properly isolated whey protein concentrates have functional properties necessary for soft drink fortification, feasibility of use will depend upon cost.