Louisiana Department of Health & Hospitals | Kathy Kliebert, Secretary

Statewide Initiatives

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Beta lactam Inhibitors Test


PHL Location

Amite Laboratory

CPT Code



Anitibiotic test for Beta lactam Inhibitors (Delvotest 5P, Charm SL-BL, Charm SL6-BL, and SNAP B-L)

Brief Description of Test

Routine raw milk and fluid dairy products are tested by Delvotest 5P for the presence of inhibitors (Beta lactam or Non-Beta lactam).

Raw commingled milk received from industry samples are tested by the method used by that particular plant to determine or confirm the presence of Beta lactam drug residue.

Possible Results

Positive for the presence of Inhibitor

Reference Range

NF (Not Found) or Positive (Inhibitor Present > than the established safe level)

Specimen Type

Raw producer or raw commingled samples and finished products.

Specimen Container(s)

Raw milk samples: collected in sterile Whirl-Pak bag or sterile plastic vial normally used by industry.

Pasteurized fluid milk products are collected in the container in which they are sold in the retail outlet.

Minimum volume accepted:

At least 40 ml

Collection Instructions

Collect a representative sample according to established protocol.

Storage and Transport Instructions

Samples must be stored on ice, the ice cannot cover the sample, and the sample must not be under water anytime during transport or upon receipt. The sample must be received so that the initial testing can be completed prior to 72 hours from original collection time. Retail samples must be received into the lab with a pilot temperature sample that is at least one-half the size of the largest size container in the ice chest. The temperature of the pilot sample upon receipt must be between 0.0-4.4¢ªC.

Causes for Rejection

  1. Temperature of pilot samples does not meet requirements.
  2. Time of receipt >72 hours from collection.
  3. Sample container is unprotected or under ice or under water when received.
  4. Sample frozen.
  5. Temperature control is missing.
  6. Sample leakage.

      7.   Unsatisfactory container.

      8.   Insufficient sample quantity.

Limitations of the Procedure

Delvotest 5P, Charm, and SNAP Tests do not specify which beta-lactam drug is present nor does the Delvotest 5P specify which non-beta-lactm drug is present.

Interfering Substances

A sample with higher than normal butterfat content will hinder the test results and cause additional measures to be applied.


  1. Standard Methods for the Examination of Dairy Products.
  2. FDA 2400 Series for the Examination of Dairy Products: Delvotet 5 Pack/Visual; Charm Safe Level, Charm Safe Level-6, Idexx-New SNAP Beta lactam
  3. US FDA/CFSAN Grade ¡°A¡± Pasteurized Milk Ordiance.
  4. Laboratory Milk and Dairy Products SOP Manual

Additional Information

A Lab 50 form must be completed according to established guidelines and submitted along with the sample.