The cold: chilling, freezing, deep-freezing, storage, delivery to the customer, a chain never broken

This lesson is part of Slaughterhouse and processing specialisation. It opens to every registered student, from free registration. Levels 1 to 5 and the tracks remain readable by everyone.

Level 12 explained why the cold is the only barrier against microbes and how to calculate the ice. This lesson runs the cold of a slaughterhouse day after day: how to load a cold room so that it really chills, how to organise deep-freezing in cycles, how long to keep each product, how to deliver to a customer 40 km away without the bag going above 4 °C, what to do during a six-hour power cut, and how to decide, figures in hand, whether a lot whose chain has broken can still be sold or must go to waste.

• ✓Run a positive and a negative cold room: loading, air circulation, door, defrosting, readings
• ✓Organise the freezing or deep-freezing of the day's lot in cycles, and measure the core temperature of a frozen product
• ✓Set storage times and manage stock by lot (first in, first out)
• ✓Deliver cold and decide, with a time-temperature grid, the fate of a product whose cold chain has broken

1. The three temperatures and what they do
2. Running the positive cold room
3. Freezing or deep-freezing the day's lot
4. Stock: first in, first out
5. Delivering cold: from the dock to the customer
6. The break: the decision grid
7. Going further

• •Three temperatures: 0-4 °C (fresh, a few days), −18 °C (frozen, months), 4-60 °C (danger zone); always measure at the core, in the thigh, probe pushed in 4 to 5 cm.
• •Positive room: product already cold, circulating air, door closed, defrosting, readings morning and evening; negative room stable at −18 °C (variation of less than 3 °C), thick insulation, condenser clean and in the shade.
• •Deep-freezing in a cell: air −30/−40 °C, −18 °C at the core in less than 4 h, carcasses not touching; freezing in a chest: one third of the volume per day, bags flat, 24 to 48 h; times: whole 3-5 days fresh, 6-9 months frozen, 9-12 months deep-frozen; offal 1-2 days fresh.
• •FIFO stock: one carton per lot, arranged by date, stock sheet on the door, inventory every Saturday, difference of more than 0.5 % to explain.
• •Delivery: product measured at departure and on arrival (signed note), full cooler with 1 kg of ice for 4 kg of fresh product, 4 to 6 hours; break: grid of degrees × hours, thawed product never refrozen, unknown = thrown away; power cut: generator or rooms kept closed (full negative 12 to 24 h, positive 4 to 6 h).