scholarly journals Microbial load reduction using modified Solar Conduction Dryer with composite filters

Author(s):  
P. Jadhav ◽  
S. Ashokkumar ◽  
N. Nagwekar

The present work studies the microbial load reduction in sapota and beet root by three different drying methods i.e. Open Sun Drying (OSD), Solar Conduction Drying (SCD) and a modified SCD with filters (SCDF). Parameters analyzed were water activity, moisture content, drying kinetics, Total Viable Counts, Total Fungal Counts and ash content. It was found that the samples dried in SCDF showed least microbial counts, faster drying times and lower ash content as comparison to OSD. This study shows that SCD and its modification provide a better alternative for low cost drying of fruits and vegetables for quality retention. Keywords: Microbial reduction; SCD Filters; Sapota; Beetroot 

2012 ◽  
Vol 108 (3) ◽  
pp. 417-426 ◽  
Author(s):  
Elisabete M.C. Alexandre ◽  
Teresa R.S. Brandão ◽  
Cristina L.M. Silva

Author(s):  
Onyinyechi Rosemary Nwosu ◽  
Omokaro Obire ◽  
D. N. Ogbonna ◽  
S. A. Wemedo

Tegillarca granosa (clam) was preserved by different drying methods. The molluscan shellfish sample was smoked dried and oven dried to predict the most effective method of drying based on the microbiological quality, proximate composition and sensory evaluation of the shellfish sample. Total viable bacterial counts of Tegillarca granosa ranged from 2.45±1.94 - 0.19±.28 x106 cfu/g, Vibrio counts ranged from 3.88±3.32 - 0.00±0.00´104 cfu/g, Pseudomonas count ranged from 3.65±3.25 - 0.00±0.00´103 cfu/g. Salmonella ranged from 3.46±2.70 – 0.00±0.00´105 cfu/g. Shigella ranged from 3.68±2.70 – 0.00±0.00 ´ 105 cfu/g, Staphylococcus counts ranged from 3.67±2.81 – 1.19±2.13 ´ 104 cfu/g. Coliform counts ranged from 5.74±2.63 - 0.00±0.00´105 cfu/g,. Fungal counts ranged from 4.13±2.75 - 0.03±0.07´104 cfu/g. The bacteria isolated were Bacillus, Enterobacter, Escherichia coli, Klebsiella, Pseudomonas, Salmonella, Shigella, Staphylococcus and Vbrio. The fungi isolated were Aspergillus flavus, Aspergillus niger, Penicillium sp and Saccharomyces cerevisiae. Results obtained showed that clam contains unacceptable counts of bacteria and fungi, higher than the specified standard limits of 1.0´105 cfu/g for bacteria 1.0´102 cfu/g for coliform. Proximate composition showed that smoked dried clam is nutritionally richer than oven dried clam. Protein content, carbohydrate content, fat content and moisture content were higher in smoked dried clam than oven dried clam while crude fiber and ash content were higher in oven dried clam. Sensory evaluation to determine the degree of liking showed that the smoke-dried clam was more preferred than the oven dried clam. The result of the microbial analysis revealed that fresh clam had higher microbial load than smoked dried and oven dried clam. Preservation by drying was effective in reducing the microbial load from the shellfish samples. The smoked drying method was more effective in reducing the microbial load of the shellfish samples than the oven dried samples.


Foods ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1325
Author(s):  
Md. Mafizur Rahman ◽  
Md. Obyedul Kalam Azad ◽  
Jasim Uddain ◽  
Md. Adnan ◽  
Md. Chayan Ali ◽  
...  

This study aimed to examine the total viable bacteria (TVBC); total coliform (TCC); fecal coliform (TFC); pathogenic Pseudomonas spp., Staphylococcus aureus, and total fungi (TF); and the effect of different low-cost disinfectants (sterile water, salt water, blanched, and vinegar) in decontamination of 12 types of fruit and 10 types of vegetables. In fruit samples, the lowest TVBC was enumerated at 3.18 ± 0.27 log CFU/g in Indian gooseberry and the highest at 6.47 ± 0.68 log CFU/g in guava. Staphylococci (2.04 ± 0.53–5.10 ± 0.02 log CFU/g), Pseudomonas (1.88 ± 0.03–5.38 ± 0.08 log CFU/g), and total fungi (2.60 ± 0.18–7.50 ± 0.15 log CFU/g) were found in all fruit samples; however, no Salmonella was detected in fruit samples. Similarly, the lowest TVBC recorded 5.67± 0.49 log CFU/g in cucumber and the highest 7.37 ± 0.06 log CFU/g in yard long bean. The Staphylococci (3.48 ± 0.13–4.81 ± 0.16 log CFU/g), Pseudomonas (3.57± 0.21– 4.75 ± 0.23 log CFU/g), TCC (1.85 ± 1.11–56.50 ± 37.14 MPN/g), TFC (1.76 ± 0.87– 3.78 ± 3.76 MPN/g), and TF (3.79 ± 0.18–4.40 ± 0.38 log CFU/g) were recorded in all vegetables samples, but no Salmonella was detected in yard long bean, pointed gourd, carrot, tomato, cucumber, or brinjal. However, vinegar showed the highest microbial load reduction of selected fruit and vegetables among the different treatments. With vinegar treatment, the highest reduction of TVBC (1.61-log) and TF (2.54-log) was observed for fruits, and TVBC (2.31-log) and TF (2.41-log) for vegetables. All the disinfectant treatments resulted in significant (p < 0.01) bacterial load reduction compared to control for the studied fruits and vegetable samples.


2020 ◽  
Vol 16 (4) ◽  
pp. 455-461
Author(s):  
Gabriela M. Baia ◽  
Otniel Freitas-Silva ◽  
Murillo F. Junior

Fruits and vegetables are foods that come into contact with various types of microorganisms from planting to their consumption. A lack or poor sanitation of these products after harvest can cause high losses due to deterioration and/ or pathogenic microorganisms. There are practically no post-harvest fungicides or bactericides with a broad spectrum of action that have no toxic residual effects and are safe. However, to minimize such problems, the use of sanitizers is an efficient device against these microorganisms. Chlorine is the most prevalent sanitizing agent because of its broad spectrum, low cost and well-established practices. However, the inevitable formation of disinfection by-products, such as trihalomethanes (THMs) and haloacetic acids (HAAs), is considered one of the main threats to food safety. Alternative sanitizers, such as chlorine dioxide (ClO2) and ozone, are becoming popular as a substitute for traditional post-harvest treatments. Thus, this review addresses the use of chlorine, chlorine dioxide and ozone emphasizing aspects, such as usage, safe application, spectrum of action and legislation. In order to ensure the quality and safety of final products, the adoption of well-prepared sanitation and sanitation programs for post-harvest fruits and vegetables is essential.


Molecules ◽  
2021 ◽  
Vol 26 (6) ◽  
pp. 1675
Author(s):  
Sengnolotha Marak ◽  
Elena Shumilina ◽  
Nutan Kaushik ◽  
Eva Falch ◽  
Alexander Dikiy

Red mature calyces of Hibiscus sabdariffa were collected from 16 different locations in Meghalaya, India. Samples were processed using shade drying (SD) and tray drying (TD). NMR spectroscopy was used to assess the metabolic composition of the calyces. In this study, 18 polar metabolites were assigned using 1D and 2D NMR spectra, and 10 of them were quantified. Proximate analysis showed that the TD method is more efficient at reducing moisture and maintaining the ash content of the Hibiscus biomass. NMR metabolomics indicates that the metabolite composition significantly differs between SD and TD samples and is more stable in TD plant processing. The differences in post-harvest drying has a greater impact on the metabolite composition of Hibiscus than the plant location.


2016 ◽  
Vol 2016 ◽  
pp. 1-5 ◽  
Author(s):  
P. T. Akonor ◽  
H. Ofori ◽  
N. T. Dziedzoave ◽  
N. K. Kortei

The influence of different drying methods on physical and nutritional properties of shrimp meat was investigated in this study. Peeled shrimps were dried separately using an air-oven dryer and a tunnel solar dryer. The drying profile of shrimp meat was determined in the two drying systems by monitoring moisture loss over the drying period. Changes in color, proximate composition, and rehydration capacity were assessed. The rate of moisture removal during solar drying was faster than the air-oven drying. The development of red color during drying was comparable among the two methods, but solar-dried shrimps appeared darker (L⁎=47.4) than the air-oven-dried (L⁎=49.0). Chemical analysis indicated that protein and fat made up nearly 20% and 2% (wb) of the shrimp meat, respectively. Protein and ash content of shrimp meat dried under the two dryer types were comparable but fat was significantly (p<0.05) higher in oven-dried meat (2.1%), compared to solar-dried meat (1.5%). Although rehydration behavior of shrimp from the two drying systems followed a similar pattern, solar-dried shrimp absorbed moisture more rapidly. The results have demonstrated that different approaches to drying may affect the physical and nutritional quality of shrimp meat differently.


2019 ◽  
Vol 5 (3) ◽  
pp. 171-183 ◽  
Author(s):  
J.W. Gatheru ◽  
F.M. Khamis ◽  
F.L.O. Ombura ◽  
J. Nonoh ◽  
C.M. Tanga ◽  
...  

The microbial composition of farmed and wild Scapsipedus icipe and Gryllus bimaculatus is presented. The aim of this study is to determine the microbial load of the two cricket species and evaluate the efficiency of processing methods (boiling, sun-drying, freeze-drying, snap-freezing and deep-frying) in reducing microbial counts. Farmed and wild species were compared based on microbial diversity. Fresh crickets had high microbial counts, bacterial and fungal populations ranged from 4.26-4.58 log cfu/g and 3.48-4.48 log cfu/g fresh weight, respectively. Upon processing, microbial counts reduced, bacterial counts ranged from 1.00-2.08 log cfu/g dry weight (boiled) and 2.70-3.34 log cfu/g dry weight (sun-dried). Fungal counts ranged from1.85-1.95 log cfu/g dry weight (boiled) and 2.95-3.51 log cfu/g dry weight (sun-dried). Deep-frying, freeze-drying and snap-freezing emerged as the best processing methods. Although there is no alarm in consuming fresh crickets, a processing method is advisable to minimize any possible risks.


Energy ◽  
2016 ◽  
Vol 99 ◽  
pp. 250-265 ◽  
Author(s):  
Yuebin Yu ◽  
Fuxin Niu ◽  
Heinz-Axel Guo ◽  
Denchai Woradechjumroen

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