Evaluation of Microbial Growth in Hospital Textiles Through Challenge Test

2020 ◽  
Author(s):  
Valentina Carraro ◽  
Adriana Sanna ◽  
Antonella Pinna ◽  
Gerolamo Carrucciu ◽  
Sara Succa ◽  
...  
Keyword(s):  
Microbial Growth ◽  
Challenge Test ◽  
Hospital Textiles

scholarly journals Effects of Acidification and Preservatives on Microbial Growth during Storage of Orange Fleshed Sweet Potato Puree

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Joyce Ndunge Musyoka ◽  
George Ooko Abong' ◽  
Daniel Mahuga Mbogo ◽  
Richard Fuchs ◽  
Jan Low ◽  
...  
Keyword(s):  
Citric Acid ◽  
Sweet Potato ◽  
Sodium Benzoate ◽  
Microbial Growth ◽  
Challenge Test ◽  
Potassium Sorbate ◽  
Food Ingredient ◽  
Chemical Preservatives ◽  
Yeasts And Molds ◽  
Orange Fleshed Sweet Potato

Orange Fleshed Sweet Potato (OFSP) puree, a versatile food ingredient, is highly perishable limiting its use in resource constrained environments. It is therefore important to develop shelf-stable puree. A challenge test study was carried out to determine the effect of combinations of chemical preservatives and acidification on microbial growth in stored puree. Puree was prepared and treated as follows: control (A); 0.05% potassium sorbate+0.05% sodium benzoate+1% citric acid (B); 0.1% potassium sorbate+0.1% sodium benzoate+1% citric acid (C); 0.2% potassium sorbate+0.2% sodium benzoate+1% citric acid (D); 1% citric acid (E). Samples were inoculated with Escherichia coli and Staphylococcus aureus at levels of 5.2 x 109 cfu/100g and 1.5 x 109 cfu/100g, respectively, before being evaluated during storage for 10 weeks at prevailing ambient temperature (15-25°C) and refrigeration temperature (4°C). Total aerobic counts, yeasts, and molds were also evaluated. E. coli and S. aureus counts declined significantly (p<0.05) by 4 log cycles in all puree treatments except for control and puree with only citric acid. Total viable count, yeasts, and molds were completely inhibited except for puree with only citric acid. Combination of chemical preservatives and acidification is effective in inhibiting pathogens and spoilage microorganisms in sweet potato puree.

scholarly journals Antimicrobial and Antioxidative Effects of Plant Powders in Raw and Cooked Minced Pork

Foods ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 661 ◽  
Author(s):  
Dea Anton ◽  
Julia Koskar ◽  
Piret Raudsepp ◽  
Kadrin Meremäe ◽  
Tanel Kaart ◽  
...  
Keyword(s):  
Lipid Oxidation ◽  
Shelf Life ◽  
Microbial Growth ◽  
Challenge Test ◽  
Meat Products ◽  
Thiobarbituric Acid ◽  
Growth Potential ◽  
Plant Materials ◽  
Plant Powders ◽  
The Impact

It is a challenge for scientists to find new plant-based food constituents simultaneously possessing antimicrobial and antioxidative properties to prolong the shelf life of meat products. In this study, various plant powders and their blends were added to minced pork to carry out a complex study of their effect on sensory characteristics, microbial growth, and lipid oxidation of the meat in raw and cooked forms during storage. Microbiological shelf life parameters were evaluated by determining the total counts of microorganisms, yeasts, and molds. The growth potential of Listeria monocytogenes was estimated by challenge testing. The impact on lipid oxidation processes was assessed using thiobarbituric acid reactive substances (TBARS) and high performance liquid chromatography (HPLC) methods. The results showed that the blend of rhubarb petioles and tomato powder added a pleasant color and a combined taste to the product, similar to the taste of salt. In raw samples, considerable microbial growth inhibition was achieved with rhubarb petioles, tomato, and their mixture. Nine treatments of cooked samples had a stronger inhibitory effect on microbial growth compared to control treatments. Among all plant powders, tomato was the most effective inhibitor of yeast and mold growth. However, the challenge test revealed that L. monocytogenes growth in cooked samples was not inhibited during shelf life. In raw samples, rhubarb roots combined with blackcurrant or chokeberry berries effectively inhibited lipid oxidation, and in cooked samples, rhubarb petioles showed a similar effect. In conclusion, it was found that powdered plant materials are well suited for use as antimicrobial and antioxidative agents in minced meat products.

Vibrio harveyi virulence gene expression in vitro and in vivo during infection in black tiger shrimp Penaeus monodon

2020 ◽  
Vol 139 ◽  
pp. 153-160
Author(s):  
S Peeralil ◽  
TC Joseph ◽  
V Murugadas ◽  
PG Akhilnath ◽  
VN Sreejith ◽  
...  
Keyword(s):  
Gene Expression ◽  
Virulence Genes ◽  
Vibrio Harveyi ◽  
Penaeus Monodon ◽  
Challenge Test ◽  
Virulence Gene ◽  
Economic Losses ◽  
Virulence Gene Expression

Luminescent Vibrio harveyi is common in sea and estuarine waters. It produces several virulence factors and negatively affects larval penaeid shrimp in hatcheries, resulting in severe economic losses to shrimp aquaculture. Although V. harveyi is an important pathogen of shrimp, its pathogenicity mechanisms have yet to be completely elucidated. In the present study, isolates of V. harveyi were isolated and characterized from diseased Penaeus monodon postlarvae from hatcheries in Kerala, India, from September to December 2016. All 23 tested isolates were positive for lipase, phospholipase, caseinase, gelatinase and chitinase activity, and 3 of the isolates (MFB32, MFB71 and MFB68) showed potential for significant biofilm formation. Based on the presence of virulence genes, the isolates of V. harveyi were grouped into 6 genotypes, predominated by vhpA+ flaB+ ser+ vhh1- luxR+ vopD- vcrD+ vscN-. One isolate from each genotype was randomly selected for in vivo virulence experiments, and the LD50 ranged from 1.7 ± 0.5 × 103 to 4.1 ± 0.1 × 105 CFU ml-1. The expression of genes during the infection in postlarvae was high in 2 of the isolates (MFB12 and MFB32), consistent with the result of the challenge test. However, in MFB19, even though all genes tested were present, their expression level was very low and likely contributed to its lack of virulence. Because of the significant variation in gene expression, the presence of virulence genes alone cannot be used as a marker for pathogenicity of V. harveyi.

Mayonnaise challenge test in children who used to avoid hen’s egg and became tolerant to one heated egg

2016 ◽  
Vol 30 (4) ◽  
pp. 562-566
Author(s):  
Yumi Koike ◽  
Noriyuki Yanagida ◽  
Takanori Imai ◽  
Sakura Sato ◽  
Motohiro Ebisawa
Keyword(s):  
Challenge Test ◽  
Hen’S Egg
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