Sporolactobacillus-isolate is verkry vanaf die mis van verskillende
herbivore diere, asook vanaf die rumen van 'h bees en die finale
afvloeiwater van 'h abattoir. Die isolate toon onderlinge verskille
ten opsigte van hulle morfologiese en fisiologiese eienskappe. Een
isolaat (L2404) het selfs verskil ten opsigte van die karakteristieke
eienskap waarop die spesienaam van Sporolactobacillus inulinus berus,
naamlik die vermoe om inulien te fermenteer.
Die gemiddelde minimum-, maksimum- en optimum pH-waardes vir groei
van Sporolactobacillus was 3,5, 8,0 en 6,5-7,0 onderskeidelik.
Die weerstandbiedendheid van Sporolactobacillus teen chemiese
preserveermiddels soos natriumni triet en kaliumsorbaat was relatief
haag. Spoorontkieming en groei van Sporolactobacillus het plaasgevind
-1 tot 'h konsentrasie van 2000 mg.Q natriumnitrie~ geen minimum
inhiberende konsentrasie waarby natriumnitriet spoorontkieming en
groei volledig geinhibeer het, kon in hierdie studie vir
Sporolactobacillus aangedui word nie. Die minimum inhiberende
konsentrasie kaliumsorbaat wat spoorontkieming en groei van spore
sowel as vegetatiewe selle van Sporolactobacillus inulinus ATCC
-1 15538 volledig onderdruk het, was 4000 mg.Q kaliumsorbaat. Vir
die isolate van Sporolactobacillus het die minimum inhiberende
konsentrasies vir volledige inhibisie van spoorontkieming en groei
(5000 mg.Q-
1
) verskil van die vir vegetatiewe groei (7000 mg.Q-
1
).
Spoorontkieming en groei van Sporolactobacillus vind by relatief lae
aw-waardes plaas en die minimum aw-waarde vir spoorontkieming en groei
was ongeveer 0,88 as aw met gliserol ingestel is. NaCl as voghouer
het 'h toksiese effek (addisioneel tot die inhibisie deur aw-verlaging)
op spoorontkieming en groei gehad, terwyl volledige inhibisie by 'h
aw-waarde van 0,956 gevind is.
Die. y D10 -waarde vir spore van Sporolactobacillus-isolate in GYP-sop
was gemiddeld 2,5 kGy en vir vegetatiewe selle 0,35-0,525 kGy •
Die antagonisms van 'h Sporolactobacillus-isolaat, L2407, teen
spesifieke 8acillus-spesies, kan moontlik aan die produksie van
bakteriosien en/of 'h ander antagonistiese produk toegeskryf word. Alhoewel laboratoriumondersoeke getoon het dat spore van
Sporolactobacillus by lae aw-waardes (<0,94) kan ontkiem en groei,
ken geen aktiewe spoorontkieming en groei in eksperimentele
rakstabiele produkte aangedui word nie. Die verskynsel kan waarskynlik
toegeskryf word aan die interaksie van verskillende faktore wat
in die produk teenwoordig is.
Positive isolation of Sporolactobacillus was made from the faeces of
different herbivores, as well as from the rumen of cattle and the
final waste water of an abattoir. The isolates showed differences
concerning their morphological and physiological properties, and one
isolate (L2404) differed by its inability to ferment inulin, which
is an essential characteristic for allocation of an isolate to the
.species Sporolactobacillus inulinus.
The average minimum-, maximum- and optimum pH-values for growth of
Sporolactobacillus were 3,5, 8,0 and 6,5-7,0 respectively.
Resistance of Sporolactobacillus to chemical preservatives was
relatively high. Germination and outgrowth of spores of
Sporolactobacillus takes place at sodium nitrite concentrations as
_1
high as 2000 mg.e It was not possible in this study to determine
a minimum inhibitory concentration for sodium nitrite, at which
germination and growth of spores was completely inhibited. The
minimum inhibitory concentration of potassium sorbate that completely
inhibited germination and growth of spores as well as vegetative
-1 growth of Sporolactobacillus inulinus ATCC 15538 was 4000 mg.e •
For the isolates of Sporolactobacillus the minimum inhibitory concentration
for germination and growth of spores and for vegetative growth
-1 -1 was5u00 mg.e and 7000 mg.e potassium sorbate respectively.
Germination and growth of spores of Sporolactobacillus take place at
relatively low aw-values. The minimum aw-value where germination and
growth of spores took place was approximately 0,88 when aw-values were
adjusted with glycerol. NaCl used as humectant for adjusting
aw-values appeared to have a toxic effect, in addition to inhibition
by reduced aw,on germination and growth of Sporolactobacillus spores.
Complete inhibition was found at an aw-value of 0,956.
010 -values for Y-irradiation of spores of Sporolactobacillus strains
in GYP-broth averaged 2,5 kGy as compared to values between 0,35 and
0,525 kGy for vegetative cells.
The antagonistic effect of a Sporolactobacillus isolate, L2407, on
specific Bacillus species was probably caused by the production of
a bacteriocin and/or another antagonistic substance. Although laboratory experiments showed that the spores of
Sporolactobacillus germinate and grow at low a -values (<0,94),no active w
germination or growth could be observed in experimental shelf-stable
products. This may be attributed to the presence of additional
inhibitory factors (or a combination thereof) present in the products.
Digitised
