Degradation of organochlorine pesticides by meat starter in liquid media and fermented sausage

The effect of meat starter on the degradation of DDT and lindane was investigated. The insignificant role of Lactobacillus plantarum in degrading p,p'-DDT and lindane presented in tryptone soya broth (TSB) and mineral salt medium (MSM) with or without 120 ppm nitrite was observed. The degradation of DDT and lindane by Micrococcus varians in TSB and MSM with or without nitrite were studied. The results indicated that DDT or lindane were degraded during the incubation period. The reduction in DDT at the end of the incubation period (15 days) was about 24.1 and 32.5% in TSB and MSM without nitrite, respectively. Corresponding values in the same media with nitrite were 37.5 and 46.4%. Regarding the reduction in lindane, it was recorded as 27.9 and 40.0% in TSB and MSM without nitrite. respectively and 38.4 and 48.4% in the same media with nitrite. The results indicated that culture media M. varians metabolized DDT mainly to DDD and lindane mainly to 2,4-, 2,5-, 2,6- and 3,4-dichlorophenol; 2,3,4- and 2,3,5-trichlorophenol; hexachlorobenzene; and pentachlorophenol. The effect of pesticides on the growth rate of meat starter was also investigated. The addition of DDT or lindane resulted in a slight decrease in counts of the strains during the initial incubation in TSB or MSM. Then the microorganisms recovered and began to grow logarithmically, but not as well as in a normal situation. The effect of fermentation stage by meat starter on DDT and lindane in fermented sausage was recorded. The results indicated that during the 72 h of fermentation, the reduction was 10 and 18% of DDT and lindane, respectively. These results confirmed that the fermentation process in meat products reduced pesticide residues and these reductions were due to the activity of meat starter. (C) 2001 Elsevier Science Ltd. All rights reserved.