Combined effect of solar drying and gamma radiation on the microbiological quality of mushrooms (Pleurotus ostreatus (Ex.Fr.)

2015 ◽  
Vol 11 (3) ◽  
2018 ◽  
Vol 14 (30) ◽  
pp. 15
Author(s):  
Gustavo Antonio Pech-González ◽  
Érika Guadalupe Ceballos-Falcón ◽  
Nicolás González-Cortés ◽  
Román Jiménez-Vera

Jalapeño pepper (Capsicum annuum L.) is a crop in protected natural areas of Tabasco, Mexico. Solar drying is a non-polluting energy that is applicable to food processing. This paper focuses on comparing the microbiological quality of dehydrated jalapeño peppers by means of three methods: direct solar (SD), electric stove (EE), and experimental solar dryer (SSE). SD drying was carried out in zinc sheet by conduction. The drying in EE was at a temperature of 70°C and the SSE has an internal temperature of 43 ° C ± 2 ° C. The dehydrated chiles were crushed in artisanal equipment, and the flour was stored in tightly closed glass containers at room temperature (22-28 ° C). The drying time was lower in the EE (7 h), followed by the SSE (8 h) and the SD (18 h). With EE, the lowest microbial load was obtained and with SD, the highest was obtained. The flour obtained with the SSE presented a concentration of microorganisms within the Mexican norms: total coliforms (25 CFU / g), Staphylococcus aureus (62 CFU / g), and aerobic mesophiles (57 CFU / g). Although the drying time and the microbial load were lower with the EE, the SSE allowed the elaboration of jalapeño pepper flour with the microbiological quality required for human consumption. Technified solar drying is a sustainable alternative for the dehydration of foods in tropical countries.


Foods ◽  
2020 ◽  
Vol 9 (5) ◽  
pp. 574 ◽  
Author(s):  
Dorothy N. Nyangena ◽  
Christopher Mutungi ◽  
Samuel Imathiu ◽  
John Kinyuru ◽  
Hippolyte Affognon ◽  
...  

Edible insects are increasingly being considered as food and feed ingredients because of their rich nutrient content. Already, edible insect farming has taken-off in Africa, but quality and safety concerns call for simple, actionable hazard control mechanisms. We examined the effects of traditional processing techniques—boiling, toasting, solar-drying, oven-drying, boiling + oven-drying, boiling + solar-drying, toasting + oven-drying, toasting + solar-drying—on the proximate composition and microbiological quality of adult Acheta domesticus and Ruspolia differens, the prepupae of Hermetia illucens and 5th instar larvae of Spodoptera littoralis. Boiling, toasting, and drying decreased the dry matter crude fat by 0.8–51% in the order: toasting > boiling > oven-drying > solar-drying, whereas the protein contents increased by 1.2–22% following the same order. Boiling and toasting decreased aerobic mesophilic bacterial populations, lowered Staphylococcus aureus, and eliminated the yeasts and moulds, Lac+ enteric bacteria, and Salmonella. Oven-drying alone marginally lowered bacterial populations as well as yeast and moulds, whereas solar-drying alone had no effect on these parameters. Oven-drying of the boiled or toasted products increased the aerobic mesophilic bacteria counts but the products remained negative on Lac+ enteric bacteria and Salmonella. Traditional processing improves microbial safety but alters the nutritional value. Species- and treatment-specific patterns exist.


Foods ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 816
Author(s):  
Simone Schill ◽  
Beatrix Stessl ◽  
Nadia Meier ◽  
Alexander Tichy ◽  
Martin Wagner ◽  
...  

In this study, the microbiological and sensory quality of cultivated mushrooms (Pleurotus ostreatus and eryngii and Lentinula edodes) available at the Austrian retail level were determined. Aerobic mesophilic bacteria (AMC), Enterobacteriaceae (EB), Pseudomonadaceae (PS), lactic acid bacteria (LAB), yeast, moulds and presumptive Bacillus cereus were enumerated at the day of purchase and after storage at 4 °C for 7 or 12 days. Additionally, the presence of Salmonella spp. and Listeria monocytogenes was investigated. Isolates of presumptive spoilage bacteria were confirmed by partial 16S rRNA sequencing. At the day of purchase, 71.2% of the samples were of high microbiological quality and grouped into the low contamination category (AMC < 5.0 log cfu/g), while the sensory quality of 67.1% was categorized as “very good or good”. After storage, the number of samples with high microbial quality was 46.6%, and only 37.0% of the samples scored as “very good or good”. The most abundant species across all mushroom samples were the Pseudomonas fluorescens species complex (58.4%) and the potential mushroom pathogen Ewingella americana (28.3%). All mushroom samples tested negative for Salmonella spp., L. monocytogenes and Bacillus cereus. The microbiological and sensory quality of the analysed mushrooms at the day of purchase and after storage was considered to be good overall. Longer transport distances were found to have a significant influence on the microbiological and sensory quality.


2015 ◽  
Vol 3 (4) ◽  
pp. 284-291 ◽  
Author(s):  
Oluwakemi Ajayi ◽  
Adewale Obadina ◽  
Micheal Idowu ◽  
Mojisola Adegunwa ◽  
Olatundun Kajihausa ◽  
...  

2005 ◽  
Vol 30 (03) ◽  
Author(s):  
J Kehr ◽  
B Morales ◽  
P Contreras ◽  
L Castillo ◽  
W Aranda

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