The legal framework is Regulation (EC) No 2073/2005 on microbiological criteria for foodstuffs, as amended. It distinguishes food safety criteria, which apply to product placed on the market, from process hygiene criteria, which indicate whether the process is under control. Buyer specifications for frozen berries commonly add limits beyond the legal minimum.
Work from the consolidated text
The regulation has been amended repeatedly. Specifications that hard-code a value from an older version cause real problems at audit, because the auditor checks against the version in force. Reference the regulation as applicable at the time of placing on the market, and keep a dated copy of the consolidated text you relied on.
What a usable clause contains
For each organism: the limit, the unit, the sampling plan expressed as n and c, the analytical method or its reference, and whether it is a safety or a hygiene criterion. Without the method and the sampling plan the number cannot be enforced, because different methods legitimately produce different answers.
Why frozen berries get extra attention
Freezing suspends microbial growth but does not reliably inactivate pathogens, and berries are often used without a further kill step. That combination means the hazard analysis, not a template, should drive which organisms you test for and how often.
Specification structure: frozen berry specifications.