Check a suspected decimal-point error before recalculating a food scan
Use a focused image check and a correction trail to distinguish 1.5 from 15 without guessing from expected nutrition values.
A missing decimal point can multiply a scanned quantity by ten. If an extracted value looks surprising, inspect the original row before changing it. Plausibility is a prompt to check, not evidence that you know what the package actually says.
Isolate the exact character
Open a close-up containing the nutrient name, number and unit together. Keep the full-panel photograph available alongside it. Enlarge the original image rather than repeatedly compressing a screenshot. If the printed mark remains unclear, take a second photograph with glare moved away from that row.
In a fictional example, the package reads 1.5 g saturated fat per 30 g, but the extracted text says 15 g. The correct concentration from the visible package is 1.5 ÷ 30 × 100 = 5 g per 100 g. The erroneous transcription would produce 50 g per 100 g. The tenfold difference is a consequence of the character error, not independent proof of which number is right.
Do not substitute the neighboring percentage
A percentage beside the amount belongs to a different field. The FDA explanation of Daily Value distinguishes nutrient quantities from their daily reference percentages. Do not copy that percentage into the amount field while trying to reconstruct an unreadable decimal.
If the printed quantity is 1.5 g and a percentage sits nearby, preserve each separately. A percentage calculation may help identify an inconsistency for investigation, but rounded printed values need not reproduce each other exactly. The readable source remains the basis for a transcription correction.
Log the repair and its reach
Record the original extraction, corrected text, source image, row name and reason. For the example, the reason is decimal visible in second photograph. Add the date and identify the correction as manual. Keep the original extraction so someone reviewing the record can see what changed.
Then find every calculation that used the mistaken amount. Recompute the per-100-g value and any custom portion results; do not repair only the displayed source row. If a shared comparison still contains the old value, issue a clearly dated replacement.
If no photograph resolves the decimal, leave the amount unavailable. A trustworthy unfinished record is preferable to an exact-looking result built on a guessed mark. You can complete the calculation when the package or manufacturer provides readable evidence.