abstract
Staphylococcal food poisoning is caused by enterotoxins excreted into foods by strains of staphylococci.
Commission Regulation 1441/2007 specifies thresholds for the presence of these toxins in foods. In this
article we report on the progress towards reference materials (RMs) for Staphylococcal enterotoxin A
(SEA) in cheese. RMs are crucial to enforce legislation and to implement and safeguard reliable measure-
ments. First, a feasibility study revealed a suitable processing procedure for cheese powders: the blank
material was prepared by cutting, grinding, freeze-drying and milling. For the spiked material, a
cheese-water slurry was spiked with SEA solution, freeze-dried and diluted with blank material to the
desired SEA concentration. Thereafter, batches of three materials (blank; two SEA concentrations) were
processed. The materials were shown to be sufficiently homogeneous, and storage at ambient tempera-
ture for 4 weeks did not indicate degradation. These results provide the basis for the development of a RM
for SEA in cheese.