# Is it possible to derive at what time during a cook process a certain temperature was reached?

I work at a frozen foods manufacturer, and we have a particular lot of product that is currently being held pending inspection, due to new regulatory requirements. To keep it concise, we need to somehow demonstrate that the product internal temperature met and sustained a particular temperature (140°F | 60°C) for 42 seconds during the cook process.

The product is -- to keep it simplified -- mostly consisting of ground chicken meat (which I believe has a heat capacity of 0.88 btu/(lboF) | 3.68 kJ/(kgoC). The product is heated via a steam tunnel, over the period of 4 minutes and 55 seconds. The product is ≈ 40°F | 4.4°C when at the start of the tunnel, and comes out at ≈ 151.6°F | 66.4°C, giving a delta of 111.6°F | 44.2°C. The product mass per unit is 0.024 kg.

Given the above information, would we be able to derive the chronological point at which the product reaches 140°F?

• What is the temperature and speed of the steam in the tunnel? – Alex Trounev Oct 1 '19 at 0:45
• Unfortunately, the control equipment for the steam tunnel consist of analog components; there is a frustrating lack of measurement data / equipment, which I have no authority or influence over. Would these be necessary variables to determine in order to answer the above? I can see if we can obtain any additional information, this falls outside of my normal departmental duties so I'm not too knowledgeable on the specifics myself. – Arctiic Oct 1 '19 at 1:00
• @Arctiic How thick is the layer of ground chicken meat? Is there a significant difference between the temperature at the surface and the internal temperature? If so, then this problem gets more difficult. – probably_someone Oct 1 '19 at 1:52
• Net Weight: 25.5g ±0.7gPCS Filling / Piece (Meat): 7.5g ±0.5 g Filling / Piece (Produce): 4.1g ±0.1g Skin / Piece Thickness: 1.25mm ±0.25mm Length: 8.5cm ±0.5cm Height: 3.25cm ±0.25cm Width: 2.35cm ±0.15cm Thickness: 1.25cm ±0.25cm – Arctiic Oct 1 '19 at 7:44

I just wanted to come back and update this, as I realized after-the-fact there was a much simpler solution to the above problem rather than making complex calculations:

• Maintain the same steam “power”, belt velocity, etc.; confirm all other factors remain the same as control sample (using the detained export product as your referenced control data).
• Increase the belt velocity so that total travel time through steam tunnel is reduced by ≥ 42 seconds (e.g., 4B Validation data showed travel time ≈ 4:55 = 295 seconds, then we would adjust until travel time is less than or equal to 253 seconds, etc.).
• If the tunnel exit product temperature comes out to ≥ 140°F | 60°C, then we can safely assume product meets the time & temperature requirement with the standard belt velocity.