scholarly journals Microbiology of Chili Bo, a Popular Malaysian Food Ingredient

1997 ◽  
Vol 60 (10) ◽  
pp. 1235-1240 ◽  
Author(s):  
JØRGEN J. LEISNER ◽  
GULAM RUSUL ◽  
BEE WAH WEE ◽  
HUEY CHERN BOO ◽  
KHARIDAH MUHAMMAD

The predominant microbial flora of a specific Malaysian food ingredient, chili bo (containing 9% ground dried chilies, 0.6% acetic acid, and 5 to 10% cornstarch, wt/vol) stored for up to 25 days at 28°C without added benzoic acid (product A) and with 7,000 ppm of added benzoic acid (product B) was examined. Aerobic plate counts for both products were initially 6.2 to 6.5 log CFU/g increasing to 8.5 log CFU/g for product A after 4 days. Aerobic plate counts for product B did not increase during storage. Lactic acid bacteria (LAB) counts increased in product A from 4.8 log CFU/g to 8.3 log CFU/g and in product B from 2.1 log CFU/g to 7 .6 log CFU/g after 17 days. Growth of yeast occurred in product A. Both products exhibited spoilage after 1 to 2 days of storage at 28°C indicated as accumulation of gas bubbles. In addition surface growth of molds (product A) or whitish discoloration (product B) was observed later in storage. For product A the predominant isolates were LAB, Bacillus pumilus, Bacillus subtilis, Staphylococcus spp., and yeasts. B. pumilus and B. subtilis predominated initially whereas the other types of microorganisms predominated after 25 days of storage. B. pumilus and B. subtilis were also predominant in product B, but after 25 days of storage a homofermentative LAB was found in higher numbers (7.6 log CFU/g). Isolates of heterofermentative LAB but not homofermentative LAB or B. pumilus or B. subtilis were able to produce gas during growth in chili bo sterilized by autoclaving at l2l°C for 15 min. Growth of heterofermentative LAB, B. pumilus, and B. subtilis was inhibited by acidifying agents, a nisin-containing supernatant, or incubation at low temperatures.

1999 ◽  
Vol 65 (2) ◽  
pp. 599-605 ◽  
Author(s):  
Jørgen J. Leisner ◽  
Bruno Pot ◽  
Henrik Christensen ◽  
Gulam Rusul ◽  
John E. Olsen ◽  
...  

ABSTRACT Ninety-two strains of lactic acid bacteria (LAB) were isolated from a Malaysian food ingredient, chili bo, stored for up to 25 days at 28°C with no benzoic acid (product A) or with 7,000 mg of benzoic acid kg−1 (product B). The strains were divided into eight groups by traditional phenotypic tests. A total of 43 strains were selected for comparison of their sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) whole-cell protein patterns with a SDS-PAGE database of LAB. Isolates from product A were identified asLactobacillus plantarum, Lactobacillus fermentum, Lactobacillus farciminis,Pediococcus acidilactici, Enterococcus faecalis, and Weissella confusa. Five strains belonging to clusters which could not be allocated to existing species by SDS-PAGE were further identified by 16S rRNA sequence comparison. One strain was distantly related to theLactobacillus casei/Pediococcus group. Two strains were related to Weissella at the genus or species level. Two other strains did not belong to any previously described 16S rRNA group of LAB and occupied an intermediate position between theL. casei/Pediococcus group and the Weissellagroup and species of Carnobacterium. The latter two strains belong to the cluster of LAB that predominated in product B. The incidence of new species and subspecies of LAB in chili bo indicate the high probability of isolation of new LAB from certain Southeast Asian foods. None of the isolates exhibited bacteriocin activity against L. plantarum ATCC 14917 and LMG 17682.


1970 ◽  
Vol 33 (11) ◽  
pp. 516-520 ◽  
Author(s):  
T. E. Minor ◽  
E. H. Marth

The effect of gradually reducing the pH of pasteurized milk with acetic, citric, hydrochloric, lactic, and phosphoric acids over periods of 4, 8, and 12 hr on growth of Staphylococcus aureus 100 in this substrate was determined. In addition, 1: 1 mixtures of lactic acid and each of the other acids, and of acetic and citric acids were evaluated for their effect on growth of this organism. To achieve a 90% reduction in growth over a 12 hr period, a final pH value of 5.2 was required for acetic, 4.9 for lactic, 4.7 for phosphoric and citric, and 4.6 for hydrochloric acid. A 99% reduction during a 12 hr period was obtained with a final pH value of 5.0 for acetic, 4.6 for lactic, 4.5 for citric, 4.1 for phosphoric, and 4.0 for hydrochloric acid. A pH value of 3.3 was required for a 99.9% reduction with hydrochloric acid, whereas the same effect was produced at a pH value of 4.9 with acetic acid. Correspondingly lower pH values were required to inhibit growth within 8 and 4 hr periods. Mixtures of acids adjusted to pH values at the borderline for growth (12 hr period) exhibited neither synergistic nor antagonistic effects between two acids.


1968 ◽  
Vol 14 (7) ◽  
pp. 749-753 ◽  
Author(s):  
Yu-Ying F. Li ◽  
Lucille K. Georg

Gas–liquid chromatography (g.l.c.) was used for the analysis of certain metabolic end products of Actinomyces propionicus, as an aid in the separation of this organism from the morphologically similar Actinomyces species, A. israelii and A. naeslundii. Profiles of the chromatograms for the major volatile acids of five strains of A. propionicus studied were found to be distinct from those of four strains of A. israelii and four strains of A. naeslundii. The ratio of propionic acid to acetic acid was approximately 50 times as great for A. propionicus as for the other Actinomyces species. Formic acid was present in significant amounts in both A. israelii and A. naeslundii, but was present only in trace amounts in A. propionicus.Two major nonvolatile acids, lactic and succinic, were identified for the A. israelii and A. naeslundii strains. One of the A. propionicus strains also showed both acids in significant amounts; however, the other four strains of A. propionicus showed succinic acid in large amounts, but only trace amounts of lactic acid.


2016 ◽  
Vol 79 (12) ◽  
pp. 2184-2189 ◽  
Author(s):  
MYEONGGEUN OH ◽  
JOONGJAE LEE ◽  
YOONHWA JEONG ◽  
MISOOK KIM

ABSTRACT We investigated the synergistic effects of lysozyme combined with organic acids to inhibit the growth of Listeria monocytogenes. The antilisterial effects of the combination of lysozyme and acetic acid, citric acid, lactic acid, malic acid, or succinic acid were evaluated using the checkerboard method and time-kill assay. The MIC was 25,000 mg/liter for lysozyme, 625 mg/liter for acetic acid, and 1,250 mg/liter for the other acids. The MBC was 10,000 mg/liter for all of the tested organic acids. The combination of lysozyme and each organic acid showed synergistic effects via the checkerboard method; however, the time-kill assay showed synergistic effects for only three combinations of 1,250 mg/liter lysozyme with succinic acid (312 and 625 mg/liter) or malic acid (625 mg/liter). The results of this study indicate that the combination of lysozyme and malic acid or succinic acid can be effectively used as a food preservative to control L. monocytogenes.


Author(s):  
SHERIDAN S. BREWER ◽  
COURTNEY A. LOWE ◽  
LARRY R. BEUCHAT ◽  
Ynes R. Ortega

Survival and growth of Salmonella and Shiga toxin-producing Escherichia coli (STEC) in kombucha prepared from four brands of commercially available kombucha kits intended for use by home brewers were investigated. Changes in microbiota responsible for fermentation were also determined. An initial population of Salmonella (6.77 log CFU/mL) decreased to below the detection limit (0.30 log CFU/mL) within 10 d in kombucha prepared from two of the four test brands. Populations of 1.85 and 1.20 log CFU/mL were detected in two brands fermented for 14 d. An initial population of STEC (7.02 log CFU/mL) decreased to <0.30 log CFU/mL in two of the four brands within 14 d; 0.20 and 0.87 log CFU/mL were detected in kombucha prepared from the other two brands. Salmonella and STEC increased in populations within 1 d in three brands of base tea used to prepare kombucha, and were stable throughout 14 d of incubation. Both pathogens steadily declined in base tea prepared from one brand of kombucha kit. Inactivation of the pathogens occurred as the pH of kombuchas decreased, but a clear correlation between rates of inactivation and decrease in pH was not evident when comparing kombuchas prepared from the four kits. Growth and peak populations of mesophilic aerobic microorganisms, yeasts, lactic acid bacteria, and acetic acid bacteria varied, depending on the kombucha kit brand. There was not strong evidence to correlate the behavior of Salmonella and STEC with any of these groups of indigenous microbiota. Results of this study show that the ability of Salmonella and STEC to survive in kombucha and base tea used to prepare kombucha is dependent on inherent differences in commercially available kombucha kits intended for use in home settings. Strict application of hygienic practices with the goal of preventing contamination with Salmonella or STEC is essential for reducing the risk of illness associated the consumption of kombucha.


1942 ◽  
Vol 6a (1) ◽  
pp. 45-52 ◽  
Author(s):  
G. J. Sigurdsson ◽  
A. J. Wood

The products of fermentation of glucose by "resting cell" suspensions of certain bacteria (Serratia, Achromobacter, and Micrococcus) isolated from decomposing cod muscle include lactic acid, acetic acid, formic acid, ethyl alcohol, carbon dioxide and small amounts of acetylmethylcarbinol. With increased acidity in the fermentation system there is a marked increase in the percentage of lactic acid formed, with a corresponding decrease in the other products. The optimum pH for the fermentation of glucose appears to be in the vicinity of 6.8—that is at, or near, the pH of fresh cod muscle.


1998 ◽  
Vol 61 (4) ◽  
pp. 487-489 ◽  
Author(s):  
MANDY A. CARR ◽  
LESLIE D. THOMPSON ◽  
MARK F. MILLER ◽  
C. BOYD RAMSEY ◽  
COLLETTE S. KASTER

The effects of chilling (normal chill or freeze chill) and trimming (hot fat trim or no fat trim) on the microbial populations of pork carcasses were evaluated. In a two-part study, composited ham, loin, belly, and shoulder samples from 30 pork carcasses had similar aerobic plate counts, averaging 5.5 log10 CFU/cm2. The nofat trim, normal chill procedure typically used in the industry, however, produced higher coliform and Staphylococcus spp. counts (P < 0.05). The hot fat trim, freeze chill treatment had the lowest lactic acid bacteria counts. Only 1 sample in 60 tested positive for Salmonella spp. Vacuum-packaged hams and loins stored at 4°C for 14 days had similar (P > 0.05) aerobic plate counts, lactic acid bacteria and Staphylococcus spp. counts regardless of trim, chill, or the location of treatment, averaging 5.7, 6.3 and 1.4 log10 CFU/cm2, respectively. Hams had higher counts than loins all three days; however, only the difference on day 2 was significant. The desire to reduce microbial populations on pork carcasses as a food-safety issue and the coming implementation of hazard analysis critical control points (HACCP) programs warrants the use of trimming and chilling methods as critical control points or good manufacturing practices and standard operating procedures in the pork slaughter, processing, and packaging industry.


In this series of communications the writer is endeavouring to show how, by varying the conditions of the experiment, it is possible to alter the proportion between the products which arise from the fermentation of glucoseand allied substances, and to point out how, by a consideration of the manner in which these products group themselves, conclusions may be drawn as to the order in which such products arise during the degradation of the glucose molecule. Substances which can be shown to arise in constant proportions under varying conditions of experiment may be considered as being produced by one and the same enzyme. In Parts II and III it was shown that the formation of lactic acid by B . coli communis ran a separate course to that of the other products, so that it may be regarded as being produced by a separate enzyme, but the other products of the fermentation, viz., succinic acid, acetic acid, formic acid, and alcohol, together with the gaseous products of the decomposition of formic acid, i. e ., carbon dioxide and hydrogen, all appeared to be grouped together and to form an alternative course for the decomposition of the glucose.


2000 ◽  
Vol 63 (1) ◽  
pp. 44-50 ◽  
Author(s):  
R. J. DELMORE ◽  
J. N. SOFOS ◽  
G. R. SCHMIDT ◽  
K. E. BELK ◽  
W. R. LLOYD ◽  
...  

Hot water and solutions of acetic acid, lactic acid, or trisodium phosphate applied by immersion or spraying, chlorine solution applied by immersion, and exposure to steam in a pasteurization system, in a cabinet, or in combination with vacuum were evaluated for their effectiveness in reducing levels of bacterial contamination on samples of beef cheek meat, large intestine, lips, liver, oxtail, and tongue. Treated samples (five per treatment) and controls were analyzed for aerobic plate counts (APCs) on tryptic soy agar and for total coliform counts (TCCs) and Escherichia coli counts (ECCs) on Petrifilm. Acetic acid (2%) immersion and trisodium phosphate (12%) spraying and immersion for 10 s were among the most effective treatments in 16, 15, and 14, respectively, of 18 comparisons for reducing APCs, TCCs, and ECCs on four or more of the six variety meats tested. Acetic acid (2%) spraying, lactic acid (2%) immersion, and hot water (78 to 80°C) spraying for 10 s were among the most effective treatments for reducing APCs, TCCs, and ECCs on four or more of the six variety meats. Chlorine (0.005%) immersion and steam were among the least effective treatments for reducing APCs, TCCs, and ECCs on variety meats. The results indicated that interventions applied to decontaminate beef carcasses can also be considered for decontamination of variety meats.


Author(s):  

Ensiling as a method of forage feed conservation is the most appropriate in conserving of crude protein (CP) enhanced forages for sustainable dairy production. This is attributed to the fact that with this method, protein dependent lactic acid bacteria (LAB) hydrolyze water soluble carbohydrates (WSC) into short chain volatile fatty acids (VFAs) which are precursors for milk synthesis while the proteins buffers the excessive organic acids to produce more acetate and propionate. The study therefore aimed at assessing the quality of Brachiaria silage which was protein supplemented with graded levels of lablab forage. To achieve this objective, wilted Brachiaria forage (Brachiaria hybrid cv Mulato II) was collected, wilted and ensiled with and Lablab purpureus forages at inclusion levels of 0%, 10%, 20%, 30% Lablab purpureus forage. The resultant 4 treatments were assessed in a completely randomized design in 3 replicates. All silages were prepared using plastic jar mini-silos to laboratory scale and then incubated at room temperature (±30°C) for 45 days. After the 45 days, chemical analysis for quantification of water soluble carbohydrate (WSC), none protein nitrogen (NH3-N), Acid detergent fiber (ADF), Neutral detergent fiber (NDF), pH, in-vitro organic matter digestibility (INVOMD), acetic acid, lactic acid and propionic acid composition were conducted. The results indicated that; none protein nitrogen, acetic acid and propionic acid composition decreased in quadratic trends with increasing legume forage inclusion to minimum values of 5.8, 48.0 and 0.7g/kg at 14.7, 1.8 and 6.0% inclusion levels of lablab forage, respectively. On the other hand, following a quadratic trend, WSC composition decreased with increase in lablab forage, with a maximum of 28.9g/kg obtained at 7.6% inclusion level of lablab forage. Generally, CP, dry matter, INVOMD and metabolizable energy of the silage increased with increase in the inclusion levels of lablab silage. Using regression equations of the response curves, NDF and ADF decreased with increasing legume forage inclusion to minimum values of 349.3 and 172.1g/kg at inclusion levels of 16.1 and 17.1%, respectively. On the other hand in-vitro organic matter digestibility increased with the increase in the lablab forage inclusion to a maximum of 49.4%. However, mineral composition of the silage was not affected by lablab forage inclusion. Since the quality of silage for dairy cows depends on short chain volatile fatty acid, fibre and crude protein composition, inclusion of lablab forage to Brachiaria hybrid cv mulato II silage at a rate of 17.1% potentially yields the best results in lactating cows.


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