HEKTOEN ENTERIC AGAR FOR MICROBIOLOGY

General description

GranuCult^® prime Hektoen Enteric Agar provides good colonial differentiation and inhibits some coliforms and other non-lactose-fermenting bacteria, thereby facilitating the isolation and differentiation of Salmonella spp. and Shigella spp. from samples such as food chain and other materials.Lactose-positive colonies have a different color from lactose-negative ones due to the presence of the two indicators for carbohydrate dissimilation: bromothymol blue and acidic fuchsin. The two additional carbohydrates, sucrose (saccharose) and salicin, also cause the color difference in colonies. The black color in the H₂S-positive colonies is due to thiosulfate as a reactive compound with an iron salt as an indicator.This culture medium is moderately to highly selective. The mixture of bile salts suppresses the growth of most of the accompanying microorganisms. The inhibitory effect of bile salts on the growth of Shigella spp. is reduced by relatively large amounts of peptone and carbohydrates, which allow good growth. Agar is the solidifying agent.

Application

GranuCult^® prime Hektoen Enteric Agar is suitable for the isolation and differentiation ofSalmonella and Shigella from the food chain and other materials.

Features and Benefits

• GranuCult^® offers superior granulated culture media.
• Safe and sustainable due to reduced risks associated with fine dust and toxic substance inhalation, resulting in a safer work environment.
• Excellent wettability, solubility, and free-flowing properties
• Convenient, with minimal component separation and clumping, even under warm or humid conditions.
• High batch-to-batch reproducibility
• Prolonged shelf life of up to five years
• High number of test strains exceeding all regulatory demands
• Granulation technology allows many supplements to be included, with no need to add these separately

Storage and Stability

Self-prepared plates can be stored in the dark and protected against evaporation:

• acc. to ISO 21567 at (5 ± 3 °C) for up to 2 weeks
• acc. to FDA-BAM at (4 ± 2 °C) for up to 30 days
• acc to Corry et al., (2012) at (5 ± 3 °C) for up to 3 weeks

Analysis Note

• Salmonella spp. produce transparent green to blue-green colonies, with or without black centers, or may appear completely black due to H₂S production.
• Shigella spp. produce green, transparent moist colonies.
• Lactose, Sucrose or Salicin fermenting gram-negative bacteria may be inhibited or produce red to salmon colored colonies with or without precipitation zone.

Other Notes

• Do not use clumped or discolored medium.
• The prepared medium is clear to slightly opalescent and blue-green to blue-grey.
• Before inoculation, allow the prepared medium to equilibrate at room temperature if it is stored at a lower temperature.
• There should be no visible moisture on the plates before use. When moisture is present, the plates should be dried for the minimum time required to remove visible moisture, following the procedure as described by EN ISO 11133.

Footnote

We offer two media types: the superior granulated GranuCult^® and the cost-efficient powdered NutriSelect^® culture media, depending on your needs.
The designations basic, plus, or prime are added to indicate the quality control level, from basic quality control to standard QC plus to prime for full regulatory compliance.

Legal Information

GRANUCULT is a registered trademark of Merck KGaA, Darmstadt, Germany

NutriSelect is a registered trademark of Merck KGaA, Darmstadt, Germany