Spoilage Of Fruit Juices Research Articles

Enzyme-Assisted Endogenous Guide DNA Generation-Mediated Pyrococcus furiosus Argonaute for Alicyclobacillus acidoterrestris Detection.

Pyrococcus furiosusArgonaute (PfAgo) emerged as a novel endonuclease for the nucleic acid test recently. However, the input of exogenous guide DNA (gDNA) to activate PfAgo has reduced its flexibility. In this work, an enzyme-assisted endogenous gDNA generation-mediated PfAgo for the target detection strategy, termed EGG-PAD, was proposed. With the aid of EcoR Ι, the target double-strand DNA was cut, producing a phosphate group at the 5' end, functioning as gDNA to activate PfAgo for nucleic acid detection. The applicability of this assay was tested in the detection ofAlicyclobacillus acidoterrestris, a bacterium causing the spoilage of fruit juice, showing excellent sensitivity and specificity, ascribed to the "duplex amplification and triple insurance" mechanism. Moreover, EGG-PAD exhibited superior versatility in the identification of common foodborne pathogens. This powerful platform could also be an on-site test tool for detecting nucleic acid-containing organisms such as tumor cell, pathogen, and virus in the future.

Effect of storage condition and preservatives on the microbial, physicochemical and sensory quality of cucumber juice and carrots juice.

Fruit juices are prone to spoilage without the use of preservatives. This study evaluated the effect of preservatives on the microbial, physicochemical and sensory quality of cucumber and carrots juices. Carrot and cucumbers fruits were extracted, filtered and treated with garlic and ginger powder and sodium benzoate. Carrot and cucumber juices without preservatives served as control. The microbial qualities of the fruit juice were determined using standard methods. Total viable count for Cucumber and carrot juices stored at ambient and refrigerated temperature increased from day 3 to day 6. Cucumber and carrot Juices with Ginger + Garlic and sodium benzoate had the least microbial count in most cases. The microbial count for refrigerated cucumber and carrot juice were less than that of juice at ambient temperature on day 3 and day 6. The sensory quality of both juices deteriorated with a longer time of storage. The organisms isolated from both cucumber and carrot juices include Staphylococcus sp, Bacillus sp, E. coli, Klebsiella sp and Salmonella sp. Bacillus had the highest frequency of occurrence of 32%, while Salmonella sp 3.5% had the least occurrence. This study has shown that microorganisms are present in fresh fruit juices, microbial spoilage occurs with longer storage time but refrigeration slows down spoilage of fruit juices, chemical preservative benzoate and ginger + garlic in combination can slow down microbial spoilage. Also, the sensory quality of juices declines with longer storage but refrigeration improves sensory quality. However, preservation of fruit juice at ambient temperature for a long duration should be discouraged to reduce microbial contamination.

Facile fabrication of metal‐organic frameworks with peroxidase‐like activity for the colorimetric detection of Alicyclobacillus acidoterrestris

AbstractAlicyclobacillus acidoterrestris (A. acidoterrestris), a kind of spore‐forming bacterium, could causes spoilage of fruit juices, which results in pecuniary losses to the industry. Unfortunately, the conventional methods used to identify this bacterium are laborious and complex. In this work, copper‐based metal‐organic frameworks (Cu‐MOFs) with intrinsic peroxidase‐like activity were fabricated by a self‐assembly method. Based on the properties of Cu‐MOFs, a colorimetric assay was developed for the detection of guaiacol, a characteristic metabolite of A. acidoterrestris and chromogenic substrate of peroxidase. Under optimal conditions, an excellent linear relationship was achieved over a range of guaiacol (0.01–0.4 mM), with a limit of detection (LOD) as low as 0.003 mM. This biosensor also showed a satisfactory sensing performance towards guaiacol, allowing the identification of A. acidoterrestris with high selectivity in a real sample. This present study provides a new perspective for the exploration of more sensitive and convenient methods for A. acidoterrestris detection.

Antimicrobial Activities of Moringa, Neem and Ginger Plant Extracts against Bacteria Associated with the Spoilage of Fruit Juice

Aim: This study aims to evaluate the antibacterial activity of Moringa, Neem, and Ginger plant extracts on the bacteria species isolated from fruit juice samples.
 Place and Duration of Study: Department of Microbiology, Michael Okpara University of Agriculture, Umudike, Abia State, Nigeria, between October 2019 and November 2019.
 Methods: The fruit juice sample was prepared and cultured on Mannitol Salt Agar (MSA), Eosin Methylene Blue (EMB), Salmonella Shigella Agar (SSA), and Blood Agar using streak plate techniques. Four (4) bacteria species were isolated and identified from the fruit juice sample. These organisms served as the test isolates. Two (2) solvents (methanol and water) were used to get a comparative result. Disc diffusion method was used to determine the antibacterial effects of the Moringa, Neem, and Ginger on the test organisms.
 Results: The methanolic extract of Moringa, Neem and Ginger was found to exhibit high degrees of antibacterial activities against the test isolates. This was shown by the clear zones of inhibition produced by the methanolic extract on the test microorganisms. The highest in-vitro antibacterial activity is 16 mm, which was exhibited by the methanolic extract of Moringa at the highest concentration of 200 mg/ml against Staphylococcus aureus. In comparison, the Methanolic extract exhibited no antibacterial activity (0.0 mm) at the lowest concentration of 50 mg/ml against all the test organisms. The minimum bactericidal concentration from this study revealed that methanolic and aqueous extract was active against Staphylococcus aureus, Shigella species, Bacillus species, and Escherichia coli. However, the water extract of Moringa demonstrated more significant antibacterial activity on Shigella species, Bacillus species, and Escherichia coli with the range of 200 mg/ml each. In contrast, methanol extract of neem demonstrated antibacterial activity on Shigella species alone, with the range of 200 mg/ml each.
 Conclusion: Moringa, Neem, and Ginger extract had both a bacteriostatic and bactericidal activity when tested in vitro using methanolic and aqueous preparation of Moringa, Neem, and Ginger extract. Therefore, these plants may be used successfully for treating illness caused by Staphylococcus aureus.

Evaluation of a New Chromogenic Agar Medium for Alicyclobacillus acidoterrestris

Spoilage of fruit juices by a thermoacidophilic spore-forming bacterium, Alicyclobacillus acidoterrestris, is a big problem for fruit juice industries worldwide. We have developed a novel chromogenic selective agar medium (EAATSM) for the isolation and enumeration of A. acidoterrestris. A. acidoterrestris strains appeared as blue colonies on the EAATSM. Other Alicyclobacillus strains appeared as white colonies or were inhibited. A study comparing EAATSM and YSG agar was carried out using artificially contaminated samples of 50 fruit juice products. The correlation coefficient between EAATSM and YSG was 0.991.

Electronic Nose for Microbiological Quality Control of Food Products

Electronic noses (ENs) have recently emerged as valuable candidates in various areas of food quality control and traceability, including microbial contamination diagnosis. In this paper, the EN technology for microbiological screening of food products is reviewed. Four paradigmatic and diverse case studies are presented: (a)Alicyclobacillusspp. spoilage of fruit juices, (b) early detection of microbial contamination in processed tomatoes, (c) screening of fungal and fumonisin contamination of maize grains, and (d) fungal contamination on green coffee beans. Despite many successful results, the high intrinsic variability of food samples together with persisting limits of the sensor technology still impairs ENs trustful applications at the industrial scale. Both advantages and drawbacks of sensor technology in food quality control are discussed. Finally, recent trends and future directions are illustrated.

Electronic nose and Alicyclobacillus spp. spoilage of fruit juices: An emerging diagnostic tool

The application of an electronic nose equipped with a Metal Oxide Semiconductor sensor array for the detection of Alicyclobacillus acidoterrestris and A. acidocaldarius artificially inoculated in peach, orange and apple fruit juices is described in this study. Overall the system was able to detect the presence of Alicyclobacillus spp. in all the tested fruit juices at 24 h from inoculation. The electronic nose could detect bacterial concentration as low as <10 2 colony forming unit/ml and it was also able to classify bacterial contamination independently of the Alicyclobacillus species. The gas chromatography–mass spectrometry characterization of the volatile profile of orange juices confirmed the existence of quantitatively different patterns between contaminated and uncontaminated samples.

Effects of the high pressure of homogenization on some spoiling micro-organisms, representative of fruit juice microflora, inoculated in saline solution

This study was aimed to investigate the effects of a high-pressure homogenization (HPH) treatment on some micro-organisms, involved in the spoilage of fruit juices. Lactobacillus plantarum, Lactobacillus brevis, Bacillus coagulans cells, Saccharomyces bayanus, Pichia membranaefaciens and Rhodotorula bacarum were separately inoculated in a saline solution (0.9% NaCl); the initial inoculum was ca. 5 log CFU ml(-1). Then, the samples were processed through a homogenizer at 10-150 MPa for 1, 2 or 3 times. Yeasts were completely inactivated at 50-110 MPa with a single pass treatment, while lactic acid bacteria counts were reduced to approximately 1 log CFU ml(-1) after a three-steps HPH processing. Yeasts were the most sensitive micro-organisms, followed by B. coagulans. On the other hand, lactic acid bacteria appeared resistant to HPH. The results of this study provided some useful information on the susceptibility of microflora of juices to homogenization; moreover, they suggested that HPH could be used successfully to inactivate yeasts.

Efficent Use of Antioxidants to Preserve Fruit Juice

In order to follow up spoilage of fruit juice: apple and orange juice, treated or non-treated with synthesis antioxidants and powder natural extracts, the samples have been analysed during production process and after storage for 5 days at a temperature of 500C (ASLD method - accelerated shelf life determination), by determining the vitamin C content, the clarity and colour, and also the water activity. Previously, antioxidants activity was calculated for the synthesized compounds and powder natural extracts.

Fate ofescherichia coli andE. coli O157∶H7 in apple juice treated with propolis extract

Fruit juices are targets of spoilage moulds, yeasts and acid tolerant bacteria. They might be contaminated with bacteria from raw materials, environment, packaging and during the handling of the product. These contaminations have frequently resulted in the spoilage of fruit juice and consequently commercial losses. The objective of this study was to determine the influence of propolis in apple juice againstEscherichia coli andE. coli O157:H7 strains of the spoilage and pathogenic bacteria. For this purpose, apple juice was obtained from fresh apples and then was pasteurised. The pH value, titrable acidity (as % malic acid) and Brix degree of this apple juice were 3.72±0.10, 0.67±0.05% and 12.1±0.01, respectively. Propolis extract at 1,2 and 5% concentrations were tested to determine ofE. coli andE. coli O157:H7 inhibition using paper disc diffusion method. The control treatment had no propolis extract. The apple juices were contaminated with these bacteria, and the activity of propolis was observed at first, 18th, 24th, 48th and 72nd hours at 4 and 25°C. The number of cells in the tubes was counted using serial dilution method. Results indicated that propolis extract at 2 and 5% concentrations had significant antimicrobial activity againstE. coli andE. coli O157:H7, therefore we can conclude that propolis extract is worthy of further study as a natural preservative for the foods prone to microbial spoilage.

Inactivation of Saccharomyces cerevisiae Suspended in Orange Juice Using High-Intensity Pulsed Electric Fields

Saccharomyces cerevisiae is often associated with the spoilage of fruit juices. The purpose of this study was to evaluate the effect of high-intensity pulsed electric field (HIPEF) treatment on the survival of S. cerevisiae suspended in orange juice. Commercial heat-sterilized orange juice was inoculated with S. cerevisiae (CECT 1319) (108 CFU/ml) and then treated by HIPEFs. The effects of HIPEF parameters (electric field strength, treatment time, pulse polarity, frequency, and pulse width) were evaluated and compared to those of heat pasteurization (90°C/min). In all of the HIPEF experiments, the temperature was kept below 39°C. S. cerevisiae cell damage induced by HIPEF treatment was observed by electron microscopy. HIPEF treatment was effective for the inactivation of S. cerevisiae in orange juice at pasteurization levels. A maximum inactivation of a 5.1-log (CFU per milliliter) reduction was achieved after exposure of S. cerevisiae to HIPEFs for 1,000 μs (4-μs pulse width) at 35 kV/cm and 200 Hz in bipolar mode. Inactivation increased as both the field strength and treatment time increased. For the same electric field strength and treatment time, inactivation decreased when the frequency and pulse width were increased. Electric pulses applied in the bipolar mode were more effective than those in the monopolar mode for destroying S. cerevisiae. HIPEF processing inactivated S. cerevisiae in orange juice, and the extent of inactivation was similar to that obtained during thermal pasteurization. HIPEF treatments caused membrane damage and had a profound effect on the intra-cellular organization of S. cerevisiae.

Detection of Guaiacol Produced by Alicyclobacillus acidoterrestris in Apple Juice by Sensory and Chromatographic Analyses, and Comparison with Spore and Vegetative Cell Populations

Spoilage of fruit juice by Alicyclobacillus acidoterrestris is characterized by a distinct medicinal or antiseptic off odor attributed to guaiacol, a metabolic by product of the bacterium. Detection of low populations of A. acidoterrestris that would precede sensory detection of guaiacol would enable juice processors to select appropriate processing and storage conditions that would minimize or eliminate spoilage. The objective of this study was to determine the recognition threshold of guaiacol in apple juice by sensory analysis and the population of A. acidoterrestris and incubation time at 21 and 37°C necessary for chemical detection of guaiacol. Commercially sterilized apple juice (pH 3.54 ± 0.04, 11.3 ± 0.3°Brix) was inoculated with a five-strain mixture of A. acidoterrestris spores (2.98 log10 CFU/ml) and stored at 21 or 37°C for up to 61 days. Using an experienced sensory panel and the forced-choice ascending concentration method of limits, the best estimate threshold (BET) for recognition of guaiacol added to uninoculated apple juice was 2.23 ppb. Numbers of A. acidoterrestris spores and cells in inoculated juice remained constant during the 61-day storage period; however, the panel detected (P ≤ 0.01) guaiacol in juice stored at 37°C within 8 days. At three of four sampling times ranging from 13 to 61 days at which the sensory panel detected (P ≤ 0.001) guaiacol, concentrations of 8.1 to 11.4 ppb were detected by chromatographic analysis. The panel detected (P ≤ 0.1 to P ≤ 0.01) guaiacol in five samples stored at 21 to 37°C for 8 to 61 days in which the compound was not detected by chromatographic analyses. It appears that guaiacol content in apple juice inoculated with A. acidoterrestris is not always correlated with numbers of cells, and the limit of sensitivity of chromatographic quantitation of the compound is higher than the BET.

Heat Resistance of Alicyclobacillus acidoterrestris Spores as Affected by Various pH Values and Organic Acids

Alicyclobacillus acidoterrestris, a thermoacidophilic sporeformer, has caused spoilage of fruit juices which had been treated with thermal processes intended to commercially sterilize the juice. The objective of this research was to document the effect of pH, acid, and temperature on the heat resistance of spores of three fruit-juice isolates of A. acidoterrestris. The thermal resistance of spores of A. acidoterrestris strains VF, WAC, and IP were studied in a model fruit-juice system composed of 12% glucose and 30mM of either citric, malic, or tartaric acid, adjusted to selected pH values ranging from 2.8 to 4.0. Decimal reduction times (D values) and inactivation rates were determined. Spores of strains VF and WAC were similarly resistant to heat under acidic conditions, while strain IP spores were less resistant. In the range of pH 2.8 to 4.0, a statistically significant effect of hydrogen ion concentration on heat resistance was observed at lower temperatures, but not at the higher temperatures. For example, at 91°C and pH 3.1 and 3.7, D values were 31.3 and 54.3 min, respectively, while at 97°C D values at pH 3.1 and 3.7 were 7.9 and 8.8 min, respectively. The type of acid did not significantly affect the heat resistance. The zD values ranged from 5.9 to 10°C, depending on the acid, pH, and the strain. The models generated from this research can be used to determine adequate thermal processes, accounting for the acid type, pH, and temperature, to destroy A. acidoterrestris spores in beverages, since this organism is able to survive the typical hot-fill and hold process (2 min at 88 to 96°C) currently used to process fruit juice.