Description

 

NUTRIENT PAD SETS –

BISMUTH – SULFITE NPS

NPS for the detection of special microorganisms or groups of microorganisms

Bismuth-Sulfite-NPS are used for the detection and isolation of Salmonella sp. The formulation is acc. to Wilson and Blair, modified. Both brilliant green and bismuth inhibit the growth of accompanying bacteria. Colonies of Salmonella, which are able to produce H2S are black because of the formation of iron sulfide. Due to the reduction of bismuth ions to metallic bismuth the colonies get a metallic halo. The medium is manufactured and quality tested in compliance with DIN EN ISO 11133:2014 standard.

 

Application: For the selective detection of salmonellae in water, food and other samples.)

 

Color: Light green

 

Profile: Dehydrated nutrient pad sets 50 mm in petri dishes, sterile

 

Recommended Membrane Filter: White with grid,  pore size 0.45 µm

 

Recommended Incubation Condition: 24 to 48 hours  at 25 to 37 °C under anaerobic conditions

 

Growth: Salmonellae form dark-brown to black colonies, usually with a light border and black halo (“fish eye”).

Storage: Dark and dry at room temperature

 

Shelf life: 2 years after sterilization

 

 

INTRODUCTION

Nutrient pad sets (NPS) are sterile dehydrated nutrient culture media that are ready for immediate use  after addition of sterile water. They are made of biologically inert cellulose cardboard that serves as a substrate  for the nutrient solution. Since it does not bind the nutrients either chemically or physically,  the nutrient components are completely available for the growth of microorganisms. The composition of the various nutrient solutions used for the various NPS comply with the formulations specified  in the relevant standards and regulations. Nutrient pad sets have a number of advantages over conventional agar media:

 

• Storage at room temperature
• Shelf life up to 2 years
• Ready for immediate use after moistening
• Easy handling

 

 

QUALITY ASSURANCE

Both the manufacturing process as well as the quality controls for the nutrient pad sets are integrated in the M&S  quality management system according to DIN EN ISO 9001:2008 and are based on GMP guidelines. Each batch of cellulose cardboard that is used as substrate for the NPS is tested for thickness  (according to DIN EN ISO 20534), grammage (according to DIN EN ISO 536) and water absorption capacity (in-house test method).  It is also tested for growth-inhibiting substances. The Petri dishes in which the impregnated nutrient pads are placed are manufactured under clean room conditions  and their sterility is checked regularly.

 

The imprignation solutions are produced using components from certified suppliers only. The weighed portions of the individual components  of the formulations are documented with their batch numbers to guarantee their traceability. The adjustment of the pH-value is also recorded.  Processing continues as soon as the solutions have been produced, i.e. the cardboard pads are then impregnated.

 

The drying process that follows impregnation takes place under controlled conditions. A service provider certified in accordance with EN ISO 13485:2003 performs the sterilisation of the NPS  in a validated process.

 

During the final inspection of the finished products, their sterility, recovery rates and if necessary any colour reactions with positive and negative microorganisms are tested. The NPS only leave our premises if they fulfil  all of the requirements. The batch related M&S quality certificate that accompanies every package confirms that the M&S quality standards have been checked and met.