Impact of raw ham quality and tumbling time on the technological properties of polyphosphate-free cooked ham.

The effect of tumbling time (5 h30, 19 h and 26 h) and raw ham quality (superior, inferior or mixed quality) on the quality of polyphosphate-free cooked ham was investigated. The water holding capacity and total yield of the polyphosphate-free tumbled hams were dependent on both tumbling time and ham quality. Higher values of both parameters were obtained with an increase in tumbling time from 5 h30 to 19 h and with superior hams. The exudate after 19 h and 26 h tumbling showed a higher gel forming ability compared to 5 h30, which, in case of polyphosphate-free cooked hams produced with mixed and inferior meat quality, resulted in a better sliceability (less holes). However, tumbling time did not affect hardness, which was only influenced by ham quality, resulting in a softer polyphosphate-free cooked ham produced with inferior ham quality compared to the other quality classes.

Volatile N-nitrosamines in meat products: Potential precursors, influence of processing, and mitigation strategies.

Meat products can be contaminated with carcinogenic N-nitrosamines, which is ascribed to the reaction between a nitrosating agent, originating from nitrite or smoke, and a secondary amine, derived from protein and lipid degradation. Although in model systems it is demonstrated that many amine containing compounds can be converted to N-nitrosamines, the yield is dependent of reaction conditions (e.g., low pH and high temperature). In this article, the influence of the composition of the meat products (e.g., pH, aw, spices) and processing (e.g., ageing, ripening, fermentation, smoking, heat treatment and storage) on the presence and availability of the amine precursors and the N-nitrosamine formation mechanism is discussed. In addition, this article explores the current N-nitrosamine mitigation strategies in order to obtain healthier and more natural meat products.

Formation of naturally occurring pigments during the production of nitrite-free dry fermented sausages.

This study investigates the potential of producing red coloured dry fermented sausages without the addition of nitrite and/or nitrate. Therefore, the formation of zinc protoporphyrin IX (Zn(II)PPIX) as naturally occurring pigment, and the interrelated protoporphyrin IX (PPIX) and heme content were evaluated during nitrite-free dry fermented sausage production at different pH conditions. Zn(II)PPIX was only able to form in dry fermented sausages at pH conditions higher than approximately 4.9. Additionally, the presence of Zn(II)PPIX increased drastically at the later phase of the production process (up to day 177), confirming that in addition to pH, time is also a crucial factor for its formation. Similarly, PPIX also accumulated in the meat products at increased pH conditions and production times. In contrast, a breakdown of heme was observed. This breakdown was more gradual and independent of pH and showed no clear relationship with the formed amounts of Zn(II)PPIX and PPIX. A statistically significant relationship between Zn(II)PPIX formation and product redness was established.

The occurrence of N-nitrosamines, residual nitrite and biogenic amines in commercial dry fermented sausages and evaluation of their occasional relation.

Regarding food borne intoxications, the accumulation of biogenic amines must be avoided in all kinds of food products. Moreover, biogenic amines can function as precursors for the formation of carcinogenic N-nitrosamines when nitrite is present. To estimate the food safety of the dry fermented sausages available on the Belgian market, a screening of the residual sodium nitrite and nitrate contents, biogenic amines and volatile N-nitrosamine concentrations was performed on 101 samples. The median concentrations of residual NaNO2 and NaNO3 were each individually lower than 20mg/kg. In general, the biogenic amine accumulation remained low at the end of shelf life. Only in one product the amounts of cadaverine and putrescine reached intoxicating levels. Concerning the occurrence of N-nitrosamines, only N-nitrosopiperidine and N-nitrosomorpholine were detected in a high number of samples (resp. 22% and 28%). No correlation between the presence of N-nitrosamines and the biogenic amines content was observed. Although the N-nitrosamines could not been linked to specific product categories, the occurrence of N-nitrosopiperidine could probably be attributed to the use of pepper.

Interactions between bacterial isolates from modified-atmosphere-packaged artisan-type cooked ham in view of the development of a bioprotective culture.

Growth and metabolite production of three dominant bacterial isolates (Carnobacterium divergens 3M14, Leuconostoc carnosum 3M42, and Brochothrix thermosphacta RMS6) from modified-atmosphere-packaged (MAP), artisan-type cooked ham were assessed for their interactions in view of the development of a bioprotective culture. During monoculture experiments in cooked ham simulation medium, Leuc. carnosum 3M42 converted the available glucose into lactic acid and ethanol, whereas the two other strains produced additional metabolites such as acetic acid and 3-methyl-1-butanol. When grown in co-culture, Leuc. carnosum 3M42 suppressed the growth and metabolism of B. thermosphacta RMS6. In contrast, a co-culture of the latter bacterium with C. divergens 3M14 led to a variety of spoilage-related metabolic compounds. Subsequently, experiments with a commercial cooked ham product indicated that Leuc. carnosum 3M42 dominated the meat matrix and improved acceptability of the product over time, hence acting as a bioprotective culture for MAP, artisan-type cooked ham.

Technology-induced selection towards the spoilage microbiota of artisan-type cooked ham packed under modified atmosphere.

The microbiota associated with a highly-perishable Belgian artisan-type cooked ham was analyzed through plating and (GTG)(5)-fingerprinting of isolates throughout its processing chain. The raw tumbled meat was characterized by the presence of a versatile microbiota around 4.8 log(cfu g(-1)), consisting of lactic acid bacteria, staphylococci, Brochothrix thermosphacta, Gram-negative bacteria, and yeasts. Pasteurisation of the ham logs reduced bacterial counts below 2 log(cfu g(-1)) and subsequent manipulations selected for leuconostocs and carnobacteria. Also, B. thermosphacta and several Enterobacteriaceae were found at this stage. During storage in an intermediate high-care area for 2 days, a selection towards certain Enterobacteriaceae (Hafnia alvei, Enterobacter spp., and Pantoea agglomerans) and lactic acid bacteria (mainly vagococci and Streptococcus parauberis) was observed. B. thermosphacta, Leuconostoc carnosum and carnobacteria were also detected, but only after allowing bacterial outgrowth by incubating the meat logs at 7 degrees C for four weeks. After a mild post-pasteurisation process and subsequent handling, incubation of the meat logs at 7 degrees C for four weeks led to outgrowth of Enterobacteriaceae (mainly Enterobacter spp. and Serratia spp.). B. thermosphacta, and lactic acid bacteria (Enterococcus faecalis, Leuc. carnosum, and Carnobacterium maltaromaticum) were also found. After slicing and packaging under modified atmosphere, the microbiota of the refrigerated end-product consisted of leuconostocs, carnobacteria, and B. thermosphacta.