7 CFR § 91.21 - Protecting samples.

---
identifier: "/us/cfr/t7/s91.21"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "7 CFR § 91.21 - Protecting samples."
title_number: 7
title_name: "Agriculture"
section_number: "91.21"
section_name: "Protecting samples."
chapter_name: "AGRICULTURAL MARKETING SERVICE (STANDARDS, INSPECTIONS, MARKETING PRACTICES), DEPARTMENT OF AGRICULTURE"
subchapter_number: "E"
subchapter_name: "COMMODITY LABORATORY TESTING PROGRAMS"
part_number: "91"
part_name: "SERVICES AND GENERAL INFORMATION"
positive_law: false
currency: "2026-03-24"
last_updated: "2026-03-24"
format_version: "1.1.0"
generator: "[email protected]"
authority: "7 U.S.C. 1622, 1624."
regulatory_source: "58 FR 42415, Aug. 9, 1993, unless otherwise noted."
cfr_part: "91"
---


# 91.21 Protecting samples.

Laboratory personnel shall protect each sample from manipulation, substitution, and improper or careless handling which would deprive the sample of its representative character from the time of receipt in the laboratory until the analysis is completed and the sample has been discarded.