Part III- Simple strategies to avoid Salmonella outbreaks Salmonella is a pernicious pathogen and eradicating it entirely from the food chain is difficult. Despite our best efforts to eradicate it from the food chain, it can still cause expensive and devastating losses - of productivity and of human life. Yet another case of human salmonellosis has been reported in the US recently, t...
Dr. Christian, Thank you very much for your highly informative article. Use of organic acid for the control of dreadful pathogens is now well established in the developed countries. Unfortunately, in the underdeveloped / developing countries, use of antibiotics is still a routine practice. In comparison to the organic acids the Antibiotic Feed Supplements are much cheaper and as no government regulations being in place for the control/check of antibiotic residue in food, use of AFS is still a first choice of the poultry producers. Secondly, in India, in order to sell the organic acid based products, some companies are suggesting lower dosage of Acidifiers in feed/ water. What are the chances of development of pH resistant bacteria, due to this practice?
Dear Dr. Anant, due to a different mode of action (the undissociated form of the organic acid is able to enter the gram-negative bacteria cell and causes loss of energy...which will weaken/kill the bacteria) resistance of bacteria against organic acids has not been described/published. The case of using low levels of acidifier is often reported in Asia. I guess in this forum the MIC - minimal inhibitory concentration - has been discussed already. There are simple rules when an acidifier can work - among them is the dosage: if you are going to kill bacteria you have to supply acids in a dosage which is at least as high as the MIC-level. Different acids have different MIC-levels. Formic acid is among the strongest, and you need at least 1.5 kg/t of formic acid to successfully counteract for instance Salmonella. But please mind! These data are from labs under controlled conditions and the pure acid is used! Therefore under the wide variety of conditions in a commercial farm with several verctors from where Salmonella could "attack" plus products on the market which contain between 20-100% acids you can guess that an effective dosage will be considerably higher than the aforementioned level. My suggestion - check your product for the amount of active ingredients and test your biosecurity/management for possible "entrance points"...
Dear Dr.Christian, Thank you for your elaborate explanation . As an antibacterial growth promoters helps to increase growth of birds, will acidifies which you have mentioned that used in food, could affect to the growth of birds?
Thanks to Dr Christian for such an important issue , in the food chains .
To combat only through Bio security at the Farm Level / production level is not only possible , for this Feed Treatment like Heat Treated feed and using of vegitable source etc and using of some orgainc product at the Feed level are also important .
The second point is Best Acidifires in the D/ WATER for microbes control has shown and proved in controling combating the salmonella at the Farm Level .
Thank you Dr christian again and for all those who wants to know that how much it work , it is in use and this is working praticaly , all over the world in developed countries like EU
thanks a lot for your explanation about how to control this dreadful pathogens. but i need your help, because in my country its not well established this control in the feed. only the use of antibiotics which also helps so much but i would like to apart about what is right quantites of formic acid per kg of food and for how long in terms of time we can be assure the food for the chiken is safe. thks Dr Christian for the article.
Dear Dr Christian,
We are very much thankful for such a wonderful forum on "Salmonella control in Food Chain". Also i totally agree with the comments from Dr. Anant Deshpande and Mr. Dahal.
Warm regards,
Dr Jaydip
Dear Dr. Christian,
Good strategic finding "use of organic acid salt" instead of the volatile formic acid in the feed to control Salmonella in poultry associated food chain. Is the action of sodium diformate pH dependent? or do the ions diffuse through the membrane as ions, if so, generation of excess proton ions does not take place within the cytoplasm. If the action is pH dependent, application of the product through the feed has to be well monitored in broiler operations where several vaccinations are done against IBD and NCD as low pH in the gut interferes with vaccines. My experience with 14 close house broiler operation, a commercially available blend of organic acids application (maintaining a pH of 4) failed to reduce mortality due to E.coli infections. I concluded, it was probably the acid blend could not reduce the pH enough due to the high buffering capacity of the feed ingredients.
D.C.Hettiarachchi - Sri Lanka
Dear Mr. Emmanuel, yes - organic acid salt - like potassium diformate; and you mentioned an available tradename - Aquaform, can also be used to enhance performance and digestibility in catfish. As of now there are trials available for the Asian catfish - Pangasius. Since the digestive system of the "catfish range" is rather similar you can expect a beneficial impact of potassium diformate in clarias as well.
Dear Dr. Hettiarachchi, you mentioned a number of limitations organic acids or organic acid blends may have. True, buffer capacity has to be kept in mind - most buffering effect comes from minerals as well as from the protein content; hence diets with a high mineral loas and/or protein content should receive higher dosages of acidifier in order to maintain a low pH in the sotmach/proventriculus. Another limitiation of organic acids is that they are readiuly available to the metabolism of the bird and only limited amounts will reach the intestine (duodenum(jejunum...) where pathogenic bacteria may proliferate. Here, the effect of organic acids cannot be the reduction of the surrounding pH per se, but rather the direct anti-microbial effect of the undissociated part of the acid (which is able to enter through the membrane of gram-negative bacteria - this causes an energy expenditure of the bacteria which will lead utlimately to bacteria cell death). Diformates have shown to be active in the intestine of animals - up to 85% of the product have still been found here, whereas pure, volatile acids may reach only in single digit percent levels the same place in the GI-tract of birds.
08.11.2011,
Dear Dr. Christian
Thank you for throwing more lights on the mechanisms of organic acids in controlling Salmonella and other gram negative bacteria. I still have a question, diformates as the name implies, should be salts of formic acid. When negatively charged formate ions enter and accumulate within the cytoplasm, as it is already in the ionic form, there will not be a generation of hydrogen ions. As there is no accumulation of H+ ions, the bacterial won't have to spend extra energy to expel them. If the formic acid enters the cytoplasm, yes, the alkaline nature of the cytoplasm will dissociate formic acid in to H+ and formate ion. The argument is true if diformate enters cytoplasm as formic acid. I would like to get cleared whether diformate enters the cyctoplasm of bacteria as formic acid.
D.C.Hettiarachchi - Sri Lanka
Dear Dr. Hettiarachchi, only the undissociated form of organic acids are able to pass through the cell membrane of gram-negative bacteria. Thus only the structure HCOOH (for formic acid) is able to pass the membrane and not H+ and COO- (the dissociated form). Since diformates are double salts of organic acids (a diformate molecule combines formic acid and formate) it is possible for the molecule (the formic acid part) to have the direct anti-bacterial effect. This also holds true for other acids, provided the fact that they arrive in the intestine, where the bacteria proliferate. And as stated before, diformate have been found to reach the intestine in animals with 85% of its ingredient still active, thus much higher than pure organic acids may reach.
08.11.2011,
Dear Dr. Ganesh Kumar Dahad
Yes, comparatively, a significant growth performance could be expected from acidifiers when there is a heavy load of unwanted bacteria present in the gut (with a poor hygienic condition in the farm). A farm with a good biosecurity and hygienic condition, the benefit could be marginal. Under such condition, Salmonella could be easily controlled with acidifiers.
D.C.Hettiarachchi - Sri Lanka
Dear Dr .Christian Lückstädt ,
We will expect to elaborate the mode of action for Formic Acid as well as for its Salt as Diformate with the help of chemical formulas.
Diagrammatic briefing will be welcomed.
regards,
Dr Jaydip
Dear Dr. Mulik,
please contact me directly under christian.lueckstaedt@addcon.com. I wil lbe than able to forward you to my collueague in India. Thanks!
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