MICROORGANISMOS PERO EN INGLÉS

PATHOGENIC MICROORGANISMS IN AGRICULTURAL SOILS

SALMA MASAOUDI EL HASNAOUYVALENTÍN ROJAS ROSA LAURA ANDREU FRANCÉS

COORDINAtors UPCT: Alberto Garre y Silvia Guillén.

INSTITUTE COORDINATOR: FRANCISCO ROIG

Index

Introduction

Goals

Methodology

Results

Conclusion

Bibliography

INTRODUCTION

What is zoonosis or anthropozoonosis?

Directly (by contact)

Animal-borne disease

By vectors, such as mosquitoes and bacteria

• Fertilizer: there is legislation for its use.
• Runoff: drag substrates and feces.

How can I get a zoonosis?

• Sanitization

• Longer conservation time

Goals

FOOD AND ITS RISKS

Every product has an industrial elaboration (ranges from 1 to 5)

Range 1

• Fresh food

• Without sanitizing treatment

• Require refrigeration

• They are the most at risk

• Preserves and semi-preserves.

• Heat treatment

• In airtight containers (cans and glass containers

Range 2

• Frozen and deep-frozen

• Frozen raw, need to be cooked

• The cold chain cannot be broken

Range 3

Range 4

• Processed frescoes

• Prepared for direct consumption

• It is recommended to wash them before consuming

Range 5

• Pre-cooked

• Heat treatment, packaging and cold storage

• Contain additives and preservatives

Escherichia coli

Strains:

Characteristics:

• From commensal to pathogenic (hemolytic uremic syndrome).
• It is usually eliminated in the feces.

• Gram negative.
• Facultative anaerobic.
• Mobile.

Escherichia coli

Bacteria ecology:

• Medium conditions:

• Media:

- Floors - Water - Food

- Temperature: 20ºC to 40ºC - pH: 6 to 8

GOALS

Familiarize ourselves with agricultural production processes and their sanitary control.

Information on Escherichia coli bacteria and variants, and potential danger due to their presence in food.

Control presence of E. coli in samples of different soils.

METHODOLOGY

After various investigations, we carried out different tests with the help of our UPCT coordinators.

We subject the bacteria to different processes

Take samples of agricultural soils and inoculate them with Escherichia coli

1. Microorganism and storage conditions

• The Escherichia coli strain that we will use will be the O157:H7 provided by CECT 5947.

• This will be stored at -80°C in a cryovial with 20% glycerol.

2. Growing conditions

• We prepared a preculture of our bacteria by "exhaustion seeding" in TSA-EL and incubated at 37°C for 24 h. It was then inoculated into 5 ml of TSB-EL and left overnight at 37°C.

• Once grown, it was inoculated again in 10 mL of TSB-EL for 24 h at 37°C. After these 24 h we obtained the culture.

sow on agar

Inoculate TSB-EL 5 ml

Inoculate TSB-EL 10 ml

3.

Inoculation of soil samples

3 soil samples were taken in 4 tubes of 5 g each corresponding to each point/time of bacterial count after various times.

0,1 ml with a concentration of 10^7 UCF/ml

20-25º resting during the weeks

4.

Recovery and microbial enumeration

• The sample was removed from the above temperature conditions, shaken, and diluted to 1 g in 9 ml of peptone water in a tube and shaken again.

• Decimal dilutions were made to facilitate microbial enumeration.

• Then we sow the dilutions -2, -3, -4, -5; which remained in TSA-EL for one day at 37ºC.

• Finally, the final count of the colonies was made and the CFU/ml were calculated.

RESULTS

Sample 1:

8,88

8,68

8,45

8,32

7,25

Time (weeks)

Sample 2:

8,702

8,702

8,22

8,15

7,45

Time (weeks)

Sample 3:

8,84

8,84

8,15

8,74

7,43

Time (weeks)

CONCLUSION

Our samples grew in similar proportions during time 0. Development of sample 1 and sample 3 is similar, increase and then decrease of microorganisms. In sample 2 microorganisms grew stable.

Food must be produced in the best hygienic conditions in order to avoid diseases from pathogens that can cause mortal diseases.

E. coli develops best in soil with a pH below 7, acidic and sandy.

BIBLIOGRAPHY

Aesan - Agencia Española de Seguridad Alimentaria y Nutrición. (s/f-b). Gob.es. Recuperado el 8 de marzo de 2023, de https://www.aesan.gob.es/AECOSAN/web/seguridad_alimentaria/detalle/enfermedades_transmision_alimentaria.htmAesan - Agencia Española de Seguridad Alimentaria y Nutrición. (s/f-c). Gob.es. Recuperado el 8 de marzo de 2023, de https://www.aesan.gob.es/AECOSAN/web/seguridad_alimentaria/seccion/gestion_riesgos.htm Aesan - Agencia Española de Seguridad Alimentaria y Nutrición. (s/f-d). Gob.es. Recuperado el 8 de marzo de 2023, de https://www.aesan.gob.es/AECOSAN/web/seguridad_alimentaria/subdetalle/Escherichia_coli.htm

BOE-A-2004-16934 Real Decreto 1940/2004, de 27 de septiembre, sobre la vigilancia de las zoonosis y los agentes zoonóticos. (s/f). Boe.es. Recuperado el 10 de marzo de 2023, de https://www.boe.es/eli/es/rd/2004/09/27/1940 10 consejos para lavar y desinfectar tus vegetales cuidando el agua. (s/f). Alianza Alimentaria. Recuperado el 10 de marzo de 2023, de https://alianzaalimentaria.org/blog/10-consejos-para-lavar-y-desinfectar-tus-vegetales-cuidando-el-agua De la I gama a la V gama. (s/f). Infoalimentacion.com. Recuperado el 10 de marzo de 2023, de https://www.infoalimentacion.com/documentos/I_gama_V_gama.htm El País, E. L. (2011, mayo 26). Pepinos españoles provocan un brote letal de “E. coli” en Alemania. Ediciones EL PAÍS S.L. https://elpais.com/sociedad/2011/05/26/actualidad/1306360815_850215.html?outputType=amp

Franz, E., Semenov, A. V., Termorshuizen, A. J., de Vos, O. J., Bokhorst, J. G., & van Bruggen, A. H. C. (2008). Manure-amended soil characteristics affecting the survival of E. coli O157:H7 in 36 Dutch soils. Environmental Microbiology, 10(2), 313–327. https://doi.org/10.1111/j.1462-2920.2007.01453.x LaSexta.com. (2021, octubre 17). La crisis del pepino: cuando Alemania acusó a España de una bacteria que se había formado en sus propias fronteras. LaSexta. https://amp.lasexta.com/programas/donde-estabas-entonces/crisis-pepino-cuando-alemania-acuso-espana-bacteria-que-habia-formado-sus-propias-fronteras_20211017616c7f2995a4560001ae4ace.html Topp, E., Welsh, M., Tien, Y.-C., Dang, A., Lazarovits, G., Conn, K., & Zhu, H. (2003). Strain-dependent variability in growth and survival of Escherichia coli in agricultural soil. FEMS Microbiology Ecology, 44(3), 303–308. https://doi.org/10.1016/S0168-6496(03)00055-2

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