Death rate of the indigenous mixed spore flora in skimmilk and skimmilk concentrates

The article contains sections titled: 1. Introduction 2. Historical Aspects 3. Composition of Milk 3.1. Milk Fat 3.1.1. Composition 3.1.2. Properties of Fat Globules 3.2. Milk Proteins 3.2.1. Major Nitrogen Fractions in Milk 3.2.2. Nomenclature and Properties of Cow's Milk Proteins 3.2.3. Caseins 3.2.4. Whey Proteins 3.2.5. Nonprotein Nitrogen (NPN) 3.3. Lactose 3.4. Minerals 3.5. Vitamins 3.6. Contaminants 4. Physical and Physicochemical Properties of Milk 5. Microbiology of Milk 6. Nutritional Value of Milk 6.1. Milk as a Nutrient Source for Humans 6.2. Health Aspects of Milk Consumption 7. Dairy Technology 7.1. Milk Production and Transport 7.2. Pretreatment in Dairies 7.3. Thermal Treatment 7.3.1. Thermal Processes 7.3.2. Effects of Heat on Milk 7.3.2.1. Effect on Microorganisms 7.3.2.2. Inactivation of Milk Enzymes 7.3.2.3. Heat‐Induced Destruction of Nutrients 7.4. Homogenization 7.5. Separation Processes 7.5.1. Microfiltration 7.5.2. Ultrafiltration 7.5.3. Nanofiltration and Reverse Osmosis 7.5.4. Ion Exchange Processes 7.5.5. Electrodialysis 7.6. Cleaning and Disinfection 7.7. Water Treatment 8. Fluid Milk 8.1. Consumer's Milk 8.1.1. Legal Classes of Consumer's Milk 8.1.2. Characterization According to Heat Treatment 8.1.3. Modified Consumer's Milks 8.1.4. Packaging of Fluid Milks and Milk Products 8.2. Reconstituted and Recombined Milk 9. Milk Products 9.1. Flavored Milk and Milk Beverages 9.2. Evaporated (Condensed) Milk 9.2.1. Technology of Concentration by Evaporation 9.2.2. Unsweetened Condensed Milk 9.2.3. Sweetened Condensed Milk 9.3. Dry Milk Products 9.3.1. Drying Processes 9.3.2. Whole and Skim Milk Powders 9.3.3. Butter and Buttermilk Powders 9.3.4. Whey Powders and Permeates 9.3.5. Milk Protein Powders 9.3.6. Powdered Infant Formulas 9.4. Fermented Milk Products 9.4.1. Legal Definitions 9.4.2. Specific Fermented Products 9.5. Cream 9.5.1. Production 9.5.2. Types of Cream 9.6. Butter 9.6.1. Production 9.6.2. Steps in Buttermaking 9.7. Anhydrous Milk Fat and Butter Oil 9.8. Dairy Spreads 9.9. Dairy Desserts 10. Quality Control 11. Legislation 12. Economic Aspects 13. Acknowledgement

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Thermal inactivation of Bacillus cereus spores in infant formula under shear conditions

Stoeckel

¹

,

Westermann

²

,

Atamer

³

et al. 2013

Dairy Sci. & Technol.

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International audienceDuring production of spray-dried infant formulas, spores of Bacillus cereus have to be inactivated in order to assure product safety. The heating step which aims at the inactivation of bacterial spores can be conducted either before concentration of the product or afterwards. However, spores tend to show increased heat resistance in concentrated products. The aim of this study was therefore to determine the inactivation kinetic parameters for the inactivation of B. cereus spores in concentrated infant formula as well as in non-concentrated infant food. Spores of B. cereus IP5832 were suspended in reconstituted infant formula (10 and 50% total solids) and heat-treated at temperatures from 90 to 110 °C under shearing at $$ \mathop{\gamma}\limits^{\bullet }=500\,{s^{-1 }} $$. Additionally, experiments at 95 °C were performed in tubes without shearing in phosphate buffer and non-concentrated infant formula. In tubes, the inactivation curves exhibited tailing. When applying heat and shear stress, linear inactivation curves were observed in both the concentrated and the non-concentrated infant formula. The kinetic parameters E a and k ref (ϑ ref = 100 °C) based on the employed Arrhenius model were 201 kJ.mol−1 and 0.011 s−1 and 201 kJ.mol−1 and 0.021 s−1 for the concentrated and the non-concentrated medium, respectively. The D values in the concentrated product at the examined temperatures were twofold higher. The heat sensitivity (z value) of the spores was not altered by concentrating the medium. The data from this study can be used to design or evaluate heating processes for concentrated products aiming at the inactivation of B. cereus spores

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Death rate of the indigenous mixed spore flora in skimmilk and skimmilk concentrates

Cited by 9 publications

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Milk and Dairy Products

Milk and Dairy Products

Milk and Dairy Products

Thermal inactivation of Bacillus cereus spores in infant formula under shear conditions

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