Microbial Counts
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Insects ◽  
2021 ◽  
Vol 13 (1) ◽  
pp. 22
Noor Van Looveren ◽  
Dries Vandeweyer ◽  
Leen Van Campenhout

Since black soldier fly larvae (BSFL, Hermetia illucens) are being produced at substantial volumes, concomitantly large amounts of the resulting by-product, called frass, are generated. This frass can potentially be applied as valuable plant fertilizer or soil improver. Since frass carries high microbial counts, potentially including foodborne pathogens, safety problems for consumers should be prevented. A heat treatment of 70 °C for 60 min is proposed to reduce harmful organisms in insect frass, based on EU regulations ((EU) No. 2021/1925). This study evaluated for the first time the impact of the proposed heat treatment on BSFL frass. This was done by applying the treatment on uninoculated frass as well as on frass inoculated with Salmonella or Clostridium perfringens at 5.0 log cfu/g. The heat treatment resulted in a reduction (maximum one log-cycle) of total viable counts and did not noticeably reduce bacterial endospores. In contrast, Enterobacteriaceae counts were reduced to below the detection limit (10 cfu/g). Heat treatment of inoculated frass resulted in absence of Salmonella in 25 g of frass and reduction of vegetative C. perfringens to below the detection limit (1 cfu/g). The proposed heat treatment appears to be appropriate to meet the microbiological regulations for insect frass.

Animals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 3553
Geruza Silveira Machado ◽  
Ana Paula Folmer Correa ◽  
Paula Gabriela da Silva Pires ◽  
Letícia Marconatto ◽  
Adriano Brandelli ◽  

Feathers are naturally made up of non-digestible proteins. Under thermal processing, total tract digestibility can be partially improved. Furthermore, Bacillus subtilis (Bs) has shown a hydrolytic effect In vitro. Then, a Bs FTC01 was selected to hydrolyze enough feathers to produce a meal, and then test the quality and inclusion in the dog’s diet to measure the apparent total tract digestibility coefficient (ATTDC) in vivo and the microorganism’s ability to survive in the gastrointestinal tract. A basal diet was added with 9.09% hydrolyzed Bs feather meal (HFMBs) or 9.09% thermally hydrolyzed feather meal (HFMT). Nine adult dogs were randomized into two 10-day blocks and fed different diets. Microbial counts were performed on feather meal, diets and feces. The Bs was less effective in digesting the feathers, which reduced the ATTDC of dry matter, crude protein, energy and increased the production of fecal DM, but the fecal score was maintained (p > 0.05). The digestible energy of HFMT and HFMBs was 18,590 J/kg and 9196 J/kg, respectively. Bacillus subtilis showed limitation to digest feather in large scale, but the resistance of Bs to digestion was observed since it grown on feces culture.

Samson A. Adeleye ◽  
Iyiola O. Oluwaleye ◽  
Taiwo O. Oni

Aim: This work gives the reports on experimental study of the effects of drying on some selected vegetables, namely fluted pumpkin (specimen I), spinach (specimen II), lettuce (specimen III), and waterleaf (specimen IV). Methodology: The vegetable specimens were dried at regulated drying temperatures of 323K, 333K, and 343K, and the percentage amount of water, fat, crude fibre, ash, protein, and carbohydrate, as well as the fungi and bacteria counts in the vegetable specimens was determined at these temperatures. Results: The results revealed that the amount of water in the vegetable specimens reached 0% earlier at the regulated drying temperature of 343K than at the other regulated drying temperatures. The results also indicated that the dried vegetable specimen II has highest fat content of 8.2%, the dried vegetable specimen III has highest crude fibre content of 14.5%, the dried vegetable specimen IV has highest ash content of 18.6%, the dried vegetable specimen I has highest protein content of 30.3%, and the dried vegetable s specimen III has highest carbohydrate content of 42.2% at the regulated drying temperature of 323K. The same trend of results was obtained for the regulated drying temperatures of 333K and 343K. Furthermore, the results showed that at the regulated drying temperature of 323K, the dried vegetable specimen III has the lowest bacteria counts of 4.3 x 107 CFU/g. The trend of result obtained for the regulated drying temperatures of 333K and 343K is similar to that of the 323K. At the regulated drying temperature of 323K, the dried vegetable specimen II has the lowest bacteria counts of 1.7 x 107 CFU/g. The same trend of results was obtained for the regulated drying temperatures of 333K and 343K. Conclusions: Drying has effects on the percentage amount of fat, crude fibre, ash, protein, and carbohydrate in the vegetable specimens. The microbial counts and the fungi counts decrease when the temperature increases. The present work can be applied in food engineering industries, and engineering in agriculture.

Foods ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 2976
Jianying Zhao ◽  
Jing Qian ◽  
Hong Zhuang ◽  
Ji Luo ◽  
Mingming Huang ◽  

This study aimed to investigate effects of plasma-activated solution (PAS) on the cell biology of Staphylococcus aureus and qualities of fresh lettuce leaves. PAS was prepared by dielectric barrier discharge plasma and incubated with S. aureus for 10–30 min or with lettuces for 10 min. Effects on cell biology were evaluated with microscopic images, cell integrity, and chemical modification of cellular components. Effects on lettuce quality were estimated with the viable microbial counts, color, contents of vitamin C and chlorophyll, and surface integrity. PAS reduced S. aureus population by 4.95-log and resulted in increased cell membrane leakage. It also resulted in increased contents of reactive oxygen species in cells, C=O bonds in peptidoglycan, and 8-hydroxydeoxyguanosine content in cellular DNA, and reduced ratios of unsaturated/saturated fatty acids in the cell membrane. PAS treatment reduced bacterial load on fresh lettuce and had no negative effects on the quality. Data suggest that PAS can be used for the disinfection of ready-to-eat fresh vegetables.

2021 ◽  
Vol 1 (1) ◽  
MIA Sarker ◽  
MA Hashem ◽  
MAK Azad ◽  
MS Ali ◽  
MM Rahman

The study was designed to evaluate the physico-chemical, microbial and sensorial quality of beef incorporated with different levels of vinegar at refrigerated storage (4±1ºC). Fresh beef samples were divided into three different batches i.e. T0 = control (without vinegar), T1 = 5% vinegar and T2 = 10% vinegar. The samples were evaluated for sensory properties (color and flavor), physico-chemical properties (pH, cooking loss, FFA, POV and TBARS) and microbial counts (TVC, TCC and TYMC) on 0, 7 and 14 days of storage at 4ºC. The obtained results showed that addition of different levels of vinegar significantly (p<0.05) influenced on sensory, physico-chemical and microbiological properties compared to control samples. Comparatively better color and flavor were found in T1 and T2 respectively among the treatments (p<0.05). Lower pH was observed in T1 and T2 compared to control treatment. POV, FFA and TBARS values were found better in T1, whereas the other treatments fluctuated slightly. The lowest microbial counts were significantly lower in higher vinegar treated groups along with at different day’s intervals in TVC, TCC and TYMC (p<0.01). It might be stated from the experiment that vinegar is a means of fresh beef preservation for a short time. From this study, it also concluded that 10% vinegar is effective for short term preservation of beef satisfactorily at refrigerated condition. 

2021 ◽  
Vol 21 (1) ◽  
Jian Wei ◽  
Kai Tong ◽  
Siqi Zhou ◽  
Hui Wang ◽  
Yinxian Wen ◽  

Abstract Background Intra-wound vancomycin powder (VP) has been used in clinical practice to prevent periprosthetic joint infection (PJI) after primary knee/hip arthroplasty. The role of intra-wound VP in the setting of debridement and implant exchange after PJI remains undefined. This study aimed to explore the efficacy and safety of intra-wound VP in the control of methicillin-resistant S. aureus (MRSA) infection after debridement and implant exchange. Methods PJI modeling by knee prosthesis implantation and MRSA inoculation, debridement and implant exchange were performed in Wistar rats successively to mimic the one-stage exchange arthroplasty of PJI patients. Two weeks of systemic vancomycin (SV) or/and intraoperative intra-wound VP of single dosage were applied after revision surgery. Results No post-surgery deaths, incision complications and signs of drug toxicity were observed. The microbial counts of SV or intra-wound VP group were significantly reduced compared with the control group, while bacteria were still detected on the bone, soft-tissue and prosthesis. The elimination of bacterial counts, along with improvement of tissue inflammation and serum inflammatory markers, were observed in the rats with SV plus intra-wound VP. Serum levels of vancomycin in all groups were lower than that of causing nephrotoxicity, while no statistic difference was observed in the serum biochemical marker among the groups. Conclusions Intra-wound VP is effective after debridement and implant exchange in our current rat PJI model. Neither SV nor intra-wound VP alone could eradicate the bacteria within a two-weeks treatment course, while SV plus intra-wound VP could eliminate the MRSA infection, without notable hepatic or renal toxicity and any incision complications.

2021 ◽  
Vol 25 (8) ◽  
pp. 1389-1393
E. Stephen ◽  
O.O. Oyebamiji ◽  
O.J. Otorkpa ◽  
S. Latena ◽  
A.I. Sunday ◽  

An assessment of mechanic workshop polluted soil treated with 16.6% lime juice (MSAL), mechanic workshop polluted soil treated with lime powder (MSLP) and mechanic workshop polluted soil treated with inorganic lime fertilizer (MSLF) was conducted for a period of 56 days. The study revealed higher microbial counts in the treated soils compared to mechanic oil free soil (MFS). The total viable bacterial counts observed ranged from 1.6×104 cfu/g to 6.8×104 cfu/g for MSF, 2.2×104 cfu/g – 26.2×104 cfu/g for MSAL, 1.2×104 cfu/g -17.2×104 cfu/g for MSLP and 6.8× 104 cfu/g – 16.0 × 104 cfu/g for MSLF while fungi counts ranged from 2.5×104 cfu/g to 6.4×104 cfu/g for MFS, 4.0×104 cfu/g – 16.4×104 cfu/g for MSAL, 2.6×104 cfu/g -3.8×104 cfu/g for MSLP and 2.1× 104 cfu/g – 4.0 × 104 cfu/g for MSLF. Organisms isolated  in the course of the study includes Pseudomonas sp,  Staphylococcus sp, Bacillus sp, Micrococcus sp, Escherichia coli,  Proteus sp, Aspergillus niger, Aspergillus fumigatus, Aspergillus flavus, Mucor sp,  Saccharomyces sp, and Rhizopus sp. The physicochemical results showed that MSAL had higher moisture content, organic matter content, organic carbon, and nitrate than MSF, MSLP and MSLF. There were significant differences in pH, organic matter content, organic carbon, nitrate and phosphorus at 0.05 probability level, but there was no significant different in the moisture content of the soil undergoing treatment. This is an indication that Lime juice has a greater potential in bioremediation of mechanic workshop polluted soil compared to lime powder and inorganic lime fertilizer.

2021 ◽  
pp. 1-10
C. Jucker ◽  
S. Belluco ◽  
S. Bellezza Oddon ◽  
A. Ricci ◽  
L. Bonizzi ◽  

The house cricket Acheta domesticus is one of the species of major interest as alternative protein source for humans in the recent research of sustainable and nutritious sources of food. However, grain feeds, feed for poultry and soybean still represent common source of feeds for the insect industry. The aim of this study was to evaluate the influence of some agro-food by-products on the growth parameters of the crickets and the nutritional composition of the final cricket meal. Our study included five by-products (maize grain distiller, fruits and vegetables, grape marc, and two brewery’s wastes), while hen feed was used as a control diet. Substrates were analysed for their microbiological contamination prior to be provided to crickets. No Listeria and Salmonella were detected, but high microbial counts were observed. Crickets grown on the given by-products showed significant differences on the insect’s weight starting from the third week. High mortality was observed on all substrates, except on maize distiller and the control diet. The final cricket meal showed a similar protein content (66-68% as is), while the lipid content was higher in the meal from cricket reared on maize distiller (22% as is). Finally, microbiological and chemical analyses on the cricket meals did not show safety concerns for the consumers. The by-products studied, except maize grain distiller, did not support an optimal cricket rearing, but more studies are necessary to identify a mix-formulation meeting the cricket nutritional requirements.

2021 ◽  
Vol 8 ◽  
Wei Zhou ◽  
Yuefang Sun ◽  
Liqiang Zou ◽  
Lei Zhou ◽  
Wei Liu

Galangal essential oil is obtained from the rhizomes of galangal with proven anti-inflammatory, antioxidant, antiviral, and antimicrobial properties, which are valuable in the food industry. To explore the effect of galangal essential oil on the quality of pineapple juice, 0.05, 0.1, 0.2, and 0.4% galangal essential emulsion were added, and their influence on the physical stability, physicochemical properties, microbial quantity, and aroma profiles of cloudy pineapple juice were evaluated. The essential oil emulsion of galangal is a milky white liquid with a strong aroma of galangal. The pH values of emulsion increased from 4.35 to 5.05 with the increase in essential oil concentration, and there was no significant difference in the particle size of the pineapple juice. The results showed that the galangal essential oil emulsion was stable and the stability of the cloudy pineapple juice was significantly enhanced by the essential oil emulsion determined using LUMiSizer. The cloudy pineapple juice with a 0.2% essential oil emulsion showed the most stability during storage. The lightness of the cloudy pineapple juice increased instantly with the essential oil emulsion addition. In addition, the microbial quantity of the cloudy pineapple juice was decreased by the individual essential oil emulsion or combined with thermal treatment to hold a longer shelf life. The microbial counts in pineapple juice treated by 0.4% essential oil emulsion and thermal treatment only increased from 1.06 to 1.59 log CFU/ml after 4 days of storage at 25°C. Additionally, the pH and total soluble solids showed a slightly increasing trend; however, the value of titratable acidity, free radical scavenging capacity, and ascorbic acid content of the cloudy pineapple juice showed no significant change. Finally, the results of the electronic nose showed that the aroma components of the pineapple juice were changed by the essential oil emulsion and thermal treatment, and the difference was especially evident in the content of the sulfur, sulfur organic, and aromatics compounds. Consequently, the results indicated that galangal essential oil emulsion can be used as juice additives to improve the quality attributes and extend the shelf-life of cloudy pineapple juice.

I. M. Ikeh ◽  
B. C. Anele ◽  
C. C. Ukanwa ◽  
S. O. Njoku

Palm wine is generally consumed due to its nutritive composition to the human body system particularly when fresh and unfermented state. A total of 20 Palm wine samples obtained from two different locations in Elele community of Rivers state, were analyzed for their microbiological qualities. A ten-fold serial dilution method was used. For Total Aerobic Plate Count (TAPC) nutrient agar was used, MacConkey for coliform count (CC), Eosin methylene blue for Escherichia coli count (EC), and Potato dextrose agar for the fungal count. Microbial counts in the palm wine sold in the drinking bar were higher than that of the palm wine tapper.  TAPC, the sample from the drinking bar has a mean value (6.73+ 0.22 log10cfu/ml) which was higher than the value obtained from the palm wine tapper (6.70+0.15log10cfu/ml). The coliform count of palm wine from the drinking bar was (6.57+ 0.10log10cfu/ml) but not significantly different from those with minimum counts (6.56+ 0.9log10cfu/ml) obtained from the tapper. Escherichia coli of palm wine from drinking bar were (5.73+ 0.23 log10cfu/ml) which were higher than (5.71+ 0.18 log10cfu/ml). The Fungal counts of palm wine sampled from the drinking bar were higher but not significantly different from those obtained from the tapper. Bacteria isolated from the two respective palm wines sampled included Staphylococcus spp 50% and 30% respectively, Klebsiella spp 20% and 30% respectively, Proteus spp 40% and 10% and 30% respectively, Aspergillus spp 30% ,  10% and Saccharomyce cerevisae 20% and 30% respectively. For the analysis of variance, bacteria and fungi count was not significant. Consumers of palm wine are advised to purchase the product from the tapper to reduce the chances of contamination.

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