Microbial risk assessment of dairy products from retail marketplaces in Basrah province, Iraq.

Background: Milk-borne bacteria cause degradation of milk products and constitute a significant risk to public health.

Aim: The objectives of the present study are to determine the microbiological quality of dairy products and to investigate pathogenic microorganisms.

Methods: A total of 60 samples of raw milk, homemade cheese, and yogurt were randomly selected from different retail marketplaces in Basrah.

Symbiotic characteristics of cysteine and methionine auxotrophs of Sinorhizobium meliloti.

Twenty one cysteine and 13 methionine auxotrophs of Sinorhizobium meliloti Rmd201 were obtained by random mutagenesis with transposon Tn5. The cysteine auxotrophs were sulfite reductase mutants and each of these auxotrophs had a mutation in cysI/cysJ gene. The methionine auxotrophs were metA/metZ, metE and metF mutants.