How to swab production for Listeria and Salmonella?

Hi evryone,

How do you get swabs from the production area using sponges for the Listeria and Salmonella studies? I mean presence and number.

For example, if you hydrate the sponge in 10 ml of neutralizing liquid, taka a 100 cm²  swab and pour in 90 ml fraser broth (Listeria) or add 25 ml of neutralizing liquid and pour in 225 ml Peptone Water (Salmonella). This is dilution 10¹. And how to make a dilution of 10⁰.

I found a message that the smear surface is equal to the amount of diluent. In another source, for 100 cm² sponge swab, add 20 ml of diluent.

Can someone explain it to me?

Hi evryone,

 

How do you get swabs from the production area using sponges for the Listeria and Salmonella studies? I mean presence and number.

For example, if you hydrate the sponge in 10 ml of neutralizing liquid, taka a 100 cm²  swab and pour in 90 ml fraser broth (Listeria) or add 25 ml of neutralizing liquid and pour in 225 ml Peptone Water (Salmonella). This is dilution 10¹. And how to make a dilution of 10⁰.

 

I found a message that the smear surface is equal to the amount of diluent. In another source, for 100 cm² sponge swab, add 20 ml of diluent.

Can someone explain it to me?

Hi,

As per my understanding, you are simply asking for the calculation of result outcome and not the sampling procedure.

Now if we consider case 1 which is 100 cm²  area and 90 ml of transfer broth your are simply making the counts at dilution -1 per 100 cm² or you could reveal the results as cfu/cm²= cfu in 1 ml *100(ml)/100(cm²).

For case 2 for Salmonella the dilution factor becomes -1 but to reveal the exact results per cm²  = cfu in 1 ml *250(ml)/100(cm²).

I guess many corporate are considering results directly per 100cm² at todays edge.

regards :smile: