Monitoring non-carbonated (‘still’) mineral waters for aerobic colonization |
| |
Authors: | H Leclerc DAA Mossel C Savage |
| |
Affiliation: | 1. Institut National de la Santé et de la Recherche Médicale, Villeneuve d''Ascq, France;2. Department of the Science of Food of Animal Origin, Faculty of Veterinary Medicine, University of Utrecht, Utrecht, The Netherlands |
| |
Abstract: | Fifty samples each of two leading brands of French, non-carbonated (‘still’) mineral waters, packed in plastic bottles, were stored in the dark for one month at approximately 20°C to allow marked proliferation of their autotrophic microbial flora. Upon completion of this challenge test 1250 ml per bottle were filtered through five membranes, which were subsequently cultured on 1/10 strength nutrient agar for 48 h at a temperature favouring the growth of thermotrophic organisms only, i.e. 42 ± 0.5°C. The numbers of colonies per one litre were below 103 in all samples and did not exceed 200 in 56–80%, depending on the brand. Identification of the isolates demonstrated strong inhibition of the psychrotrophic. Gram-negative types, predominating in the association flora of stored still waters and preponderance of Gram-positive, catalase-positive, facultatively anaerobic cocci. Consequently, a Reference Value for the thermotrophic autotrophic colony count per 1 ml in still, commercial mineral waters of the order m = 1 and M = 5 seems justified. It is emphasized that, besides examining for these trivial organism, the usual tests for marker bacteria (Escherichia coli and Lancefield group D streptococci) and Pseudomonas aeruginosa should always be carried out. |
| |
Keywords: | Mineral water non-carbonated Autotrophic bacteria Thermotrophic bacteria Bacteriological reference values |
本文献已被 ScienceDirect 等数据库收录! |
|