INVESTIGADORES
CASTRO Marcela Paola
congresos y reuniones científicas
Título:
BIOPROTECTIVE CULTURE FOR COOKED MEAT PRODUCTS: EVALUATING SALTS EFFECTS
Autor/es:
C. HERMAN; ALVAREZ O.; CASTRO M.; CAYRÉ, M.E.; VIGNOLO G.M.; GARRO O.A.
Lugar:
S.M. de Tucumán
Reunión:
Simposio; IV Simposio Internacional de Bacterias Lácticas; 2013
Institución organizadora:
CERELA-CONICET
Resumen:
The
preservation of meat products is increasingly directed towards biocontrol using
bacteriocinogenic Lactobacillus species
as protective cultures to inhibit the growth of undesirable microorganisms.
However, food preservation using in situ
bacteriocin production requires an adequate knowledge of the relationship
between cell growth and bacteriocin production as a function of the intrinsic
and extrinsic factors that prevail in the food matrix. The aim of this work was
to evaluate the combined effect of NaCl and NaNO2 concentrations,
under refrigeration (7°C), on the antimicrobial activity of Lactobacillus curvatus 409 a strain
isolated from artisanal bologna type sausage, which showed good properties as a
bioprotective culture in cooked meat products. A central composite design (22
+ star) was applied, being the independent variables: NaCl concentration (0.2,
1, 3, 5 and 5.8 % w/v) and NaNO2 concentration (6, 35, 105, 175 and
204 mg/L). Cell growth was tested on MRS broth supplemented with the
aforementioned additives assessing
optical density measurements at 600nm for 192 hours. Antimicrobial activity
against Listeria innocua was carried
out by means of the agar well diffusion assay and expressed as arbitrary units
per ml (AU/ml). Time needed to reach the highest antimicrobial activity was
used as response variable. L. curvatus 409 was able to grow and produce antimicrobial
substances under all conditions tested. Analysis of results indicated that the
linear effect of NaCl and NaNO2 had a significant effect on response
variable. An increase in salts concentrations drove to an increase in the time
necessary to reach the highest activity. Values found were in the range between
148 and 192 hours. The influence of NaNO2
resulted less pronounced when compared to NaCl. In addition, the higher the
concentrations of NaCl and NaNO2, the lower the values of maximum
activity. These values varied between a minimum of 50 UA/ml and a maximum of 400
UA/ml. The interaction effect between NaCl and NaNO2 was significant
indicating that high NaCl concentrations together with high NaNO2
concentrations have a greater impact on time than with low NaNO2
concentrations. The results suggest that the effectiveness of L. curvatus 409 as a protective culture
for cooked meat products could be affected by NaCl and NaNO2
concentrations, additives inherent to these products. Despite this fact, L. curvatus 409 could be a valuable
additional hurdle in the preservation of cooked meat products. Further studies
have to be carried out to evaluate this strain behavior in the control of Listeria spp in these products.