Benzoate production by lactic acid bacteria in laban.
Benzoates are legally preservatives permitted in many countries and in a variete of food products (Ahlborg, 1977). These preservatives are used for their antimicrobial activity against yeasts, fungi and some bacteria (Chipley, 1993). The use of benzoic acid is not allowed by most countries in many dairy products (Fondu et al., 1984). In Morocco, benzoates are also not allowed to be used in milk products (MAMVA and MSP, 1997). This seems to be explained by the fact that benzoates are more toxic and less effective than sorbates, which are used extensively in dairy products (Branen et al., 1990; Puttemans et al., 1985; Fondu et al., 1984; Sofos and Busta, 1981).
The effect of lben fermentation on benzoate production had not been until now investigated. Milk contains only small amounts of benzoates (Chandan et al., 1977; Hatanaka and Kaneda, 1986), but some fermented dairy products would contain higher levels of benzoates (Sieber et al., 1995). Bertling (1985) reported that the presence of Benzoic acid in milk products is not due to a deliberate addition, but may be the result of unintentional contamination from rennet, veterinary drugs, teat dips, addition of fruit flavorings which contain benzoic acid or bacterial conversion of hippuric acid to benzoic acid. Chandan et al.,(1977) indicated that benzoic acid is produced by lactic acid bacteria used to prepare cultured dairy products. Nishimoto et al., (1969) reported that lactic acid bacteria can convert milk hippuric acid to benzoic acid.
In view of the preservative nature of benzoates as well as their implication in technological and legislative aspects of dairy product additives, the present study was carried out to examine the effects of hippurate addition on benzoate levels during mesophilic fermentation and to evaluate the contribution of benzoate to the shelf-life of lben.
The hippurate effects on benzoate levels during mesophilic fermentation as well as the effects of benzoate on yeast growth in traditional lben were examined. To determine the effect of hippurate on benzoate levels during lben fermentation process, supplied samples and non-supplied samples with hippurate were taken at regular intervals. The production of benzoic acid in lben increased as the levels of added hippurate increased, and this increase followed a linear regression. The conversion of hippuric acid to benzoic acid was between 25-30 and 40-50% at the end of the fermentation process for industrial and traditional lben, respectively.
To determine the effect of benzoate on yeast growth in lben, samples which were supplied with hippurate were fermented and the lben samples prepared were contaminated with a yeast culture and stored in a refrigerator for 7 days. The results showed that all the benzoate levels produced in lben did not stop yeast growth, but did increase the lag phases. These were estimated to 1, 1.5, 2 and 3 days respectively for the benzoic acid levels of 6.8, 14.1, 30.0 and 46.1 ppm.
- Ahlborg U.G., Dick J., Eriksson H.B. 1977. Data on preservatives in food. Var-Foeda 29 (2) : 41-96.
- Bertling, L.K. 1985. Free of preservatives but still positive for benzoic acid? Deutsche-Milchwirtschaft 36(5)135-136.
- Branen A.L., Davidson P.M., and Salminen S. 1990. Food Additives. Ed. Marcel Dekker Inc. New York
- Chandan R.C., Gordon J.F. and Morrisson A. 1977. Natural benzoate content of dairy products. Milchwissenschaft 32(9):534-537.
- Chipley, J.R. 1993. Sodium benzoate and benzoic acid. In Antimicrobials in Foods, 2nd Edition, ed. P.M. Davidson & A.L. Branen. Marcel Dekker, New York, NY, USA.
- Hatanaka H. and Kaneda Y. 1986. Rapid and simultaneous analysis of hippuric and benzoic acids in fermented milk or raw milk by HPLC. J. Food Hyg. Soc. Japan, 27(1):81-86.
- Fondu M., van Gindertael-Zegers de Beyl H. Bronkers G. Stein A. and Carton P. 1984. Food Additives Tables, updated edition. Ed. Elsevier, Amsterdam.
- MAMVA andMSP. 1997. Circulaire conjointe, N° 001/97 du Ministère de l’Agriculture et de la Mise en Valeur Agricole et du Ministère de la Santé Publique relative à l’utilisation des additifs alimentaires.
- Puttemans M. L., Branders C., Dryon L., & Massart D. L. 1985. Extraction of organic acids by ion-pair formation with tri-noctylamine. VI: Determination of sorbic acid, benzoic acid and saccharin in yogurt. J. Assoc. Off. Anal. Chem., 68, 80-82.
- Saidi B. Tiyal H. and Faid M. 2002 .Benzoate production by lactic acid bacteria in labanActes Inst. Agro. Veter
- Sieber R., Butikofer U., Baumann E and Bosset J.O. 1995. Benzoic acid as a natural compound in cultured dairy products and cheese. Internat. Dairy J. 5:227-246.
- Sofos J. N. and Busta F.F. 1981. Antimicrobial Activity of sorbate. J. Food Protec. 44(8):614-622.
- Nishimoto T., Uyeta M. and Taue S. 1969. Precursor of benzoic acid in fermented milk. J. Food Hyg. Soc. Japan, 10, 410-413.
Camel milk (Camelus dromadarius) was studied for a microbiological and physico-chemical characterization. Standard plate count (SPC), total and fecal coliforms, enterococci, staphylococci, Lactic acid bacteria and Clostridium were evaluated. Results showed that the microbial profiles were relatively low for all the microorganisms studied. The average SPC was 5 x 104 cfu/ml, staphylococci numbers ranged from less than 1 cfu/ml to 5 x 103 cfu/ml. Enterococci reached an average of 20 cfu/ml. Coliforms were the most abundant microorganisms in camel milk and ranged from less than 1 cfu/ml to 8 x 104 cfu/ml. 33.33 % of staphylococci isolated were coagulase positive and among the isolates collected from all samples no E.coli was detected. Lactic acid bacteria counts in the samples showed an average of 104 cfu/ml while yeasts ranged from less than 1 cfu/ml to 9 x 104 cfu/ml. Clostridium and Salamonella were not detected.