BS Food Science & Technology
What the Food Science & Technology domain tests
The BS Food Science & Technology domain applies chemistry, biology, and processing principles to food composition, safety, and preservation. Questions may ask you to interpret a label, a microbial count, or a processing step.
Core rules and concepts
- Macronutrients: carbohydrates, proteins, and lipids differ in energy density and functional role; water is a major component and affects stability.
- Water activity (aw) measures available water for microbial growth, not total moisture content. Lower aw generally slows spoilage.
- pH and titratable acidity are different measures. Pathogens have growth ranges; refrigeration slows but does not sterilise.
- Thermal processing uses D-values and z-values. A D-value is the time at a given temperature for a one-log reduction.
- HACCP identifies hazards and critical control points; it is preventive, not a final-product test.
Worked example
A process reduces a microbial population from 10^6 to 10^2 cells at 121°C. The D-value is 1.5 min. How long is needed? Reasoning: the reduction is 10^6 → 10^2, which is 4 log cycles. Time = 4 × 1.5 = 6.0 min. A one-log reduction would take 1.5 min; two logs, 3.0 min. Count the log cycles carefully rather than subtracting powers and adding an extra log.
Traps that cost marks
Confusing dry-basis and wet-basis percentages, treating pH as a linear scale, mixing minutes with seconds, and assuming “natural” means microbiologically safe. In label calculations, check whether the percentage is by mass or by energy.