Nos volières

Microbiological analysis of seed sprouts in Norway.

Robertson LJ, Johannessen GS, Gjerde BK, Loncarevic S.

Department of Pharmacology, Microbiology and Food Hygiene, The Norwegian School of Veterinary Science, Oslo. lucy.robertson@veths.no

As part of larger survey of microbial contamination of fruits and vegetables in Norway, four different sprouted seed products were analysed for bacterial and parasitic contaminants (n = 300 for bacterial analyses and n = from 17 to 171 for parasite analyses, depending on parasite). Escherichia coli O157, Salmonella, Listeria monocytogenes, Cyclospora oocysts, Ascaris eggs and other helminth parasites were not detected in any of the sprout samples. Thermotolerant coliform bacteria (TCB) were isolated from approximately 25% of the sprout samples, with the highest percentage of TCB positive samples in alfalfa sprouts. Most TCB were Enterobacter spp. and Klebsiella. E. coli was isolated from 8 of 62 TCB positive mung bean sprout samples. Cryptosporidium oocysts were detected in 8% of the sprout samples and Giardia cysts were detected in 2% of the samples. All the Cryptosporidium positive samples, and most of the Giardia positive samples, were mung bean sprouts. Parasite concentrations in positive samples were low (between 1 and 3 oocysts/cysts per 50 g sprouts). Sprout irrigation water was also analysed for microbial contaminants. E. coli O157 and L. monocytogenes were not detected. TCB were isolated from approximately 40% of the water samples. Salmonella reading was isolated from three samples of spent irrigation water on 3 consecutive days. Cryptosporidium and Giardia were also isolated from spent irrigation water. Additionally, eight samples of unsprouted mung bean seed were analysed for Cryptosporidium oocysts and Giardia cysts. One or both of these parasites were detected in six of the unsprouted seed samples at concentrations of between 1 and 5 oocysts/cysts per 100 g unsprouted seed. Whilst our results support spent irrigation water as the most suitable matrix for testing for bacteria, unsprouted seed is considered the more useful matrix for analysing for parasite contaminants.

Sprouted seeds

Many aviculturists like to feed sprouted seeds to their birds because most birds seem to relish them. Germination does affect the nutrition of the seed, and research shows that the effects vary with different species of seed. The most consistent changes are a decrease in phytate phosphorus, and increase in available phosphorus, and increased protein digestibility. Increases and decreases in vitamin and mineral levels appear to be highly dependent on species studied The decrease in phytate phosphorus may be significant to mineral and protein utilization. High level of phytate phosphorus interfere with the availability of calcium, magnesium, zinc, iron, and protein because the formation of insoluble complexes that are not readily absorbed. Sprouted seeds can be an important source of microbial contamination unless antimicorbial agents are used in the sprouting medium. Chlorine at 50 ppm has been shown to reduce contamination.

Bean sprouts are considered highly nutritious and are thought to stimulate breeding by many aviculturists. However, sprouts can be source of bacterial or fungal pathogens, and they should be avoided or rinsed with dilute hypochlorite, chlorherxidine or peroxide solutions prior to feeding.

Les germes de haricots sont considérés comme trés nutritifs et beaucoup d'éleveurs pensent qu'ils stimulent la reproduction. Cependant, les germes peuvent etre source de pathogenes bacteriens ou fongiques et ils devraient etre évités ou rincés avec de la javel diluée, des solutions de chlorhexidine ou d'eau oxygenée avant d'etre donnés.

Beaucoup d'aviculteurs aiment fournir des graines germées a leurs oiseaux, car la plupart des oiseaux semblent les aimer. La germination affecte le contenu nutritif des graines, et des recherches ont montré que les effets varient selon l'especes de graine.
Le principal changement est une diminution en phosphore phytates, une augmentation de phosphore disponible et une augmentation de la digestibilité des proteines. Les variations en vitamines et en minéraux semblent etre hautement dependant de l'espece étudiée. La diminution en phosphore phytates modifient l'utilisation des minéraux et des protéines.
Des concentrations élevées en phosphore phytates interferent avec la disponibilité du calcium, du magnesium, du zinc, du fer et des proteines a cause de la formation de complexes insolubles qui ne sont pas absorbés. Les graines germées peuvent etre une source importante de contamination microbienne a moins qu'un agent anti-microbien ne soit utilisé dans le milieu de germination. De la javel a 50 ppm a montré son efficacité pour reduire la contamination.

Pharmazie. 1999 Jun;54(6):452-6. Related Articles, Links


Aspects of the antimicrobial efficacy of grapefruit seed extract and its relation to preservative substances contained.

von Woedtke T, Schluter B, Pflegel P, Lindequist U, Julich WD.

Institute of Pharmacy, Ernst Moritz Arndt University, Greifswald, Germany.

The antimicrobial efficacy as well as the content of preservative agents of six commercially available grapefruit seed extracts were examined. Five of the six extracts showed a high growth inhibiting activity against the test germs Bacillus subtilis SBUG 14, Micrococcus flavus SBUG 16, Staphylococcus aureus SBUG 11, Serratia marcescens SBUG 9, Escherichia coli SBUG 17, Proteus mirabilis SBUG 47, and Candida maltosa SBUG 700. In all of the antimicrobial active grapefruit seed extracts, the preservative benzethonium chloride was detected by thin layer chromatography. Additionally, three extracts contained the preserving substances triclosan and methyl parabene. In only one of the grapefruit seed extracts tested no preservative agent was found. However, with this extract as well as with several self-made extracts from seed and juiceless pulp of grapefruits (Citrus paradisi) no antimicrobial activity could be detected (standard serial broth dilution assay, agar diffusion test). Thus, it is concluded that the potent as well as nearly universal antimicrobial activity being attributed to grapefruit seed extract is merely due to the synthetic preservative agents contained within. Natural products with antimicrobial activity do not appear to be present.