You are the Technical Manager in a frozen foods company

You are the Technical Manager in a frozen foods company. A potential customer has supplied you with its specifications for a frozen ready meal consisting of beef and vegetables. During the freezing process they require verification that all components of the meal kit reach -18 °C, a standard request. They also require that all components, especially the vegetables, go from 0 °C to -5 °C in two hours or less. Why do you think they have this additional requirement? Justify using scientific reasoning. Your answer should also clearly explain how freezing preserves food and why water is released when the beef and vegetables are thawed.