9 CFR § 101.7 - Seed organisms.

---
identifier: "/us/cfr/t9/s101.7"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "9 CFR § 101.7 - Seed organisms."
title_number: 9
title_name: "Animals and Animal Products"
section_number: "101.7"
section_name: "Seed organisms."
chapter_name: "ANIMAL AND PLANT HEALTH INSPECTION SERVICE, DEPARTMENT OF AGRICULTURE"
subchapter_number: "E"
subchapter_name: "VIRUSES, SERUMS, TOXINS, AND ANALOGOUS PRODUCTS; ORGANISMS AND VECTORS"
part_number: "101"
part_name: "DEFINITIONS"
positive_law: false
currency: "2026-03-24"
last_updated: "2026-03-24"
format_version: "1.1.0"
generator: "[email protected]"
authority: "21 U.S.C. 151-159; 7 CFR 2.22, 2.80, and 371.4."
regulatory_source: "38 FR 8426, Apr. 2, 1973, unless otherwise noted."
cfr_part: "101"
---


# 101.7 Seed organisms.

When used in conjunction with or in reference to seed organisms, the following shall mean:

(a) *Master Seed.* An organism at a specific passage level which has been selected and permanently stored by the producer from which all other seed passages are derived within permitted levels.

(b) *Working Seed.* An organism at a passage level between Master Seed and Production Seed.

(c) *Production Seed.* An organism at a specified passage level which is used without further propagation for initiating preparation of a fraction.

[49 FR 22625, May 31, 1984]