This news article was originally written in Spanish. It has been automatically translated for your convenience. Reasonable efforts have been made to provide an accurate translation, however, no automated translation is perfect nor is it intended to replace a human translator. The original article in Spanish can be viewed at Estrategias para incrementar la seguridad alimentaria en jamón curado loncheado
Listeriosis is an infection caused by the ingestion of contaminated food and originates mainly in the consumer-ready products
Strategies to increase food security in sliced cured ham
May 31, 2011
A study by researchers of the programme of food safety of Irta
, has evaluated the effect of the bioconservación and high hydrostatic pressure in cured ham sliced and packaged into the void with Listeria monocytogenes. Research has shown that the combination of both antimicrobial barriers, can contribute significantly to the control of the microorganism in this meat product ready for consumption (or ten,) for its acronym in English, 'ready to eat'.
' Listeria monocytogenes' is the name of the bacterium responsible for listeriosis, an infection caused by the ingestion of contaminated food and originates mainly in the consumer-ready products. Today, countries like United States, Japan, Canada and Australia applied the policy of 'zero tolerance' in relation to the presence of l. monocytogenes in RTE products, even for those that do not favour the growth of the pathogen (such as cured ham). In order to meet the health requirements, the food industry often applied treatments post-processing that provide for the reduction or elimination of bacteria, or agents well antimicrobial drugs to inhibit their growth during the useful life of products.
In that context, the treatments in vogue today to ensure safe ten products are high hydrostatic pressures (APHs) and the natural biopreservatives as the pathogens, protein substances produced by certain microbial strains capable of inhibiting the growth of certain pathogenic bacteria.
Biopreservatives or high hydrostatic pressures?
The most studied pathogens include nisin, produced by the micro-organism ' Lactococcus lactis subsp. lactis' and used for the production of cheese. Thanks to a broad spectrum antibacterial activity, its implementation can be carried out by inoculation of bacterial culture producer, by direct to the meat mass addition or by incorporation in the surface of the product, either directly or through the so-called "active packaging". While the effectiveness of nisin against ' l. monocytogenes' has been demonstrated in fresh or fermented and cooked as Burger and ham products, there are few studies in relation to the cured ham.
On the other hand, for years, the RTE meat products by high pressure treatment is recognized internationally as a process of post-envasado and very valid listericida. This technology allows a pasteurization the product of cold, helping to maintain the organoleptic properties, to increase security and to prolong the useful life of the food, especially in products with nutritional, sensory features and/or functional termosensibles.
The Irta researchers have evaluated the combined effect of two treatments in 2 types of cured hams from white pigs and pork meat. The first was subjected to a period of maduración-secado shorter than the second, so it was less dry than the Iberian (water activity, tow
, of 0.92 and 0.88, respectively). After inoculation with ' l. monocytogenes', prepared three lots for each type of ham sliced and packaged in a vacuum: without addition of bioconservante (batch control) and by direct of nisin on the surface of the slices and indirect incorporation by grieving movies of slices (packaging active). Half of each group of samples, was also processed by a team of high pressures to 600 MPa for 5 minutes.
Control batches stored in terms of cooling (to 8 ° C) for 2 months, confirmed that the cured ham does not allow the growth of ' l. monocytogenes', even when the product is not very dry. The direct application of nisin on the surface of the slices, on the other hand, showed significant antibacterial action, with a reduction immediately in the counting of the pathogen and more important for the driest product. Finally, the use of the bacteriocin using packaging assets also served a listericida effect during storage of the ham, although it was minor compared to the direct application of the bioconservante and without significant differences depending on the degree of maturation of the product.
High pressure hydrostatic, as postprocessing treatment anti-listeria, are more effective than the implementation of the antimicrobial agent nisin
Considering the treatment by APH, the study showed an immediate reduction of the levels of ' l. monocytogenes', although the magnitude of the effect was greater for the less mature product. The presence of nisin in pressurized samples also increased the inactivation of the pathogen, especially in the direct application of the bioconservante on the surface of the ham. In addition, values achieved after the combination of both treatments were superior to the theoretical amount of the inactivaciones obtained separately. However, the additional effect not was observed in the case of application of nisin by packaging assets, observed inactivation was similar to that obtained after treatment by APH in batch control.
The results of research show that nisin, applied in a way, constitutes a valid antimicrobial strategy to improve the security of the cured ham sliced and packaged into the void, as reflected in the American legislation in relation to the control of ' l. monocytogenes' in the consumer-ready products. However, the APH, such as post-processing treatment anti-listeria, are more effective (both immediately and long term), that the implementation of the antimicrobial agent nisin, although the combination of both procedures would contribute even more significantly to the control of ' l. monocytogenes' in the ten cured ham.
-Hereu a., Bover-Cid S., d. Garriga, Eymerich T., 2011 ' High hydrostatic pressure and biopreservation of dry-cured ham to meet the Food Safety Objectives for Listeria monocytogenes' International Journal of Food Microbiology.