なぜ1960年代アポロ計画の「宇宙食ルール（HACCP）」が、現代の病院とサーバーを守る確かな防壁になるのか？

#![forbid(unsafe_code)]

#[derive(Debug, Clone, Copy)]
pub struct CcpThermalSpec {
    pub reference_temp_c: f64, // e.g., 75.0°C (vegetative pathogens) or 121.1°C (C. botulinum spores)
    pub z_value_c: f64,        // Temperature change required for 10x change in D-value (e.g., 7.5°C or 10.0°C)
    pub min_equivalent_secs: f64, // Required equivalent lethality time at reference_temp_c (e.g., 60.0s)
}

#[derive(Debug, Clone, Copy, PartialEq)]
pub struct CcpBatchVerdict {
    pub accumulated_f_secs: f64,
    pub passed_critical_limit: bool,
    pub min_recorded_temp_c: f64,
}

/// Integrates the cumulative thermal lethality F = ∫ 10^((T(t) - T_ref)/z) dt
/// using the composite trapezoidal rule over time-series core temperature sensor samples.
pub fn evaluate_haccp_ccp_lethality(
    samples_temp_c: &[f64],
    sample_interval_secs: f64,
    spec: &CcpThermalSpec,
) -> CcpBatchVerdict {
    if samples_temp_c.len() < 2 || sample_interval_secs <= 0.0 || spec.z_value_c <= 0.0 {
        return CcpBatchVerdict {
            accumulated_f_secs: 0.0,
            passed_critical_limit: false,
            min_recorded_temp_c: 0.0,
        };
    }

    let rate = |temp_c: f64| -> f64 {
        if temp_c < 55.0 {
            0.0 — Below sub-lethal threshold, no microbial destruction occurs
        } else {
            10.0_f64.powf((temp_c - spec.reference_temp_c) / spec.z_value_c)
        }
    };

    let mut f_sum = 0.0;
    let mut min_t = samples_temp_c[0];
    for window in samples_temp_c.windows(2) {
        let (t0, t1) = (window[0], window[1]);
        if t1 < min_t {
            min_t = t1;
        }
        f_sum += 0.5 * (rate(t0) + rate(t1)) * sample_interval_secs;
    }

    CcpBatchVerdict {
        accumulated_f_secs: f_sum,
        passed_critical_limit: f_sum >= spec.min_equivalent_secs,
        min_recorded_temp_c: min_t,
    }
}