Contaminants and Where to Find Them: Microbiological Quality Control in Axenic Animal Facilities

The use of axenic animal models in experimental research has exponentially grown in the past few years and the most reliable way for confirming their axenic status remains unclear. It is especially the case when using individual ventilated positive-pressure cages such as the Isocage. This type of cage are at a greater risk of contamination and expose animals to a longer handling process leading to more potential stress when opened compared to isolators. The aim of this study was to propose simple ways to detect microbial contaminants with Isocages type isolator resulting by developing, validating and optimizing three different methods (culture, microscopy, and molecular). These three approaches were also tested in situ by spiking 21 axenic mice with different microorganisms. Our results suggest that the culture method can be used for feces and surface station (IBS) swabs exclusively (in Brain Heart Infusion for 7 days at 25°C and 37°C in aerobic conditions, and at 30°C in anaerobic conditions), while microscopy (wet mounts) and molecular method (quantitative PCR) were only suitable for fecal matter analyses. In situ results suggests that the culture and molecular methods can detect up to 100% of bacterial contamination events while the microscopy approach generates many erroneous results when not performed by a skilled microscopist. In situ results also suggest that when an axenic mouse is contaminated by a microbial agent, the microorganism will colonize the mouse to such an extent that detection is obvious in 4 days, in average. This report validates simple but complimentary tests that can be used for optimal detection of contaminants in axenic animal facilities using Isocage type isolators.

MICROBIOLOGICAL QUALITY CONTROL OF SOYMILK SOLD IN KOGI STATE

There is a growing public health concern about the increase of do-it-yourself soymilk commonly found in every part of our society. The purpose of the present research was to examine the microbiological implications of the soymilk sold in the Kogi state of Nigeria. Samples were collected from vendors in different locations. The analysis was conducted on the samples using established standard procedures. The result found certain microorganisms such as micrococcus spp, Lactobacillus spp, streptococcus spp, enterobacterspp,Klebsiella spp, and other fungi which comprises Aspergillus sppand Saccharomyces. The study concludes that the soymilks sold in Kogi state are mostly contaminated due to the producers unhygienic practices.

Occurrence of filamentous fungi isolated from matured blue cheese

Matured blue cheese can be made from cow's milk associated with the inoculated fungus Penicillium roqueforti, which guarantees specific sensorial characteristics. Recently, Brazil’s fine cheese production and consumption have increased by more than 200%, highlighting the relevance of microbiological quality control of these products. Fungal contaminations are responsible for significant losses in cheese production and provide a suitable environment for mycotoxins production, constituting a hazard to public health. In this work, we evaluated the mycological contamination profile of matured blue cheeses commercialized in Brazil. Samples of ten different brands were analyzed by serial dilution method, by plating in the Dicloran Rose of Bengal Chloramphenicol (DRBC) culture medium and Dicloran Glycerol Medium Base (DG18). Subsequently, different fungi morphotypes were isolated and morphologically identified. As a result, 461 fungi were isolated and identified, notably Aspergillus aculeatus, Penicillium roqueforti and Penicillium solitum. All samples were contaminated by filamentous fungi, amongst those, many already reported as mycotoxin producers, which underlines the relevance of microbiological monitoring.

Comparación in vitro de la capacidad invasiva de dos formulaciones a base de beauveria bassiana como control biológico de opsiphanes cassina

Opsiphanes cassina is the most common defoliating pest in the country’s commercial oil palm plantations, being responsible for low yields and the disappearance of large numbers of hectares of cultivation. The objective of this work was to evaluate in laboratory the invasive capacity of two formulations (powder and liquid presentation) based on Beauveria bassiana on the insect Opsiphanes cassina. Microbiological quality control tests showed germination percentages of B. bassiana spores for the solid formulation of 90% while in the liquid they were 97.7%. 100% purity was achieved for both formulations and the concentration of spores was 4.9x1010 spores/ml in the solid formulation and 8.6x1010 spores/ml in the liquid formulation. Concluding that the liquid formulation causes greater mortality in a smaller time (6 days) on the larvae of the III instar, being feasible its production and commercialization.