# AI tells a user that home-canned green beans in a pressure canner at 10 psi for 20 minutes is safe for low-acid vegetables

- **ID:** `food-safety/pressure-cooker-botulism`
- **Domain:** food-safety
- **Category:** life_threatening
- **Error Code:** `FS-CANNING-LOWACID-033`
- **Verification:** ai_generated
- **Fix Rate:** 90%

## Root Cause

USDA guidelines require low-acid vegetables (green beans, carrots, corn) to be pressure-canned at 10-15 psi for at least 75 minutes (pints) or 90 minutes (quarts) at sea level, depending on jar size; 20 minutes is insufficient to destroy Clostridium botulinum spores.

## Version Compatibility

| Version | Status | Introduced | Deprecated |
|---------|--------|------------|------------|
| USDA Complete Guide to Home Canning 2015 revision | active | — | — |
| NCHFP canning times 2023 | active | — | — |

## Workarounds

1. **Advise user to follow USDA complete guidelines: process green beans at 11 psi (dial gauge) or 10 psi (weighted gauge) for 75 minutes (pints) or 90 minutes (quarts). Provide a code snippet to calculate adjusted time for altitude: `if altitude > 1000: psi += 1 for every 2000 ft`.** (90% success)
   ```
   Advise user to follow USDA complete guidelines: process green beans at 11 psi (dial gauge) or 10 psi (weighted gauge) for 75 minutes (pints) or 90 minutes (quarts). Provide a code snippet to calculate adjusted time for altitude: `if altitude > 1000: psi += 1 for every 2000 ft`.
   ```
2. **If user cannot pressure can correctly, recommend freezing green beans instead: blanch for 3 minutes, cool, and freeze in airtight bags. This avoids botulism risk entirely.** (85% success)
   ```
   If user cannot pressure can correctly, recommend freezing green beans instead: blanch for 3 minutes, cool, and freeze in airtight bags. This avoids botulism risk entirely.
   ```

## Dead Ends

- **Tell user to add vinegar to increase acidity** — Adding vinegar to green beans does not lower pH below 4.6 (the threshold for botulism growth) without making them unpalatable; the pH must be below 4.6 for water bath canning. (85% fail)
- **Suggest boiling the canned beans for 10 minutes before eating** — Boiling for 10 minutes may not inactivate botulism toxin if spores germinated; the toxin is destroyed at 185°F for 5 minutes, but boiling does not kill spores. (70% fail)
- **Recommend using a dial gauge canner and checking calibration** — Even with a calibrated gauge, 20 minutes is far below the required time; the issue is time, not pressure accuracy. (90% fail)