The effect of dietary supplement with 17% high-amylose barley (Hordeum vulgare, HAB) 'Karmose' on boar taint was studied on 72 crossbred entire male pigs (Sus scrofa domestica) Swedish Yorkshire dams x Swedish Landrace sires). All pigs were fed the same commercial diet (12.4 MJ metabolised energy (ME) per kg, digestible crude protein (CP) 13.5%) twice a day until the average live weight (LW) in the pen reached 100 +- 11.8 kg. Then, 32 out of 72 pigs received an HAB diet. Half of these pigs received HAB for 14 days and the other half for 28 days. The pigs were slaughtered at an average LW of 122.3 +- 8.6 kg (age 167.2 +- 7.5 days). The HAB diet did not affect performance, carcass and meat quality characteristics, and puberty status, but reduced plasma skatole levels in the pigs (least squares means, 3.6 vs. 2.0 ng mlE-1, P = 0.037). However, this diet failed to reduce skatole, indole and androstenone levels in fat (P is greater than 0.10). Nevertheless, it is desirable to continue investigation of HAB to optimise the feeding procedure to improve efficiency of HAB effect on fat skatole levels. Additionally, validation of a greater amount of HAB in the diet should be performed.

The non-spore forming gram-positive bacterium Listeria monocytogenes is a food pathogen bacterium and a causative agent of listeriosis. The aim of the study was to determine the survival limits of L. monocytogenes inoculated in manufactured vacuum-packed cold smoked pork depending on shelf time, supported by water activity (aw) and pH values. Enumeration of L. monocytogenes colony forming units per gram (cfu gE-1) was done according to ISO standard. Water activity (aw) and pH values in pork samples were more or less constant and supported L. monocytogenes growth. The behaviour of L. monocytogenes in cold-smoked sliced pork by shelf time, when environmental factors changed minimally and supported growth, largely depended on the initial contamination level. A lag-phase of bacterial growing process before exponential growth rate of inoculated L. monocytogenes depended on initial cell concentration and had 10 days step level if storage temperature was approximately 5 deg C. A significant Pearson’s correlation (p is less than 0.01) was established between the microbiological test values of L. monocytogenes count changes in sliced and packed cold-smoked pork during storage time of 60 days. The main parameter which maintained negative polynomial growth rate of L. monocytogenes in cold-smoked pork was the decrease of live cell concentration in samples below lg 2.0. The experiments were done at the Faculty of Veterinary Medicine of Latvia University of Agriculture and at a sausage manufacturer’s laboratory.

Fresh meat is a highly perishable product due to its biological composition as it serves as an ideal environment for the growth and propagation of microorganisms and common food-borne pathogens. High pressure processing (HPP) is a cold pasteurization treatment to extend shelf-life while preserving the sensory and nutritional characteristics of the product. The aim of this research was to evaluate the effects of HPP on the fresh porcine Musculus longissimus lumborum microbial load and related physical properties (pH, water activity aw, and moisture content). Vacuum packed meat samples were treated at 50, 100, 200, 300, 400, and 500 MPa for 1, 5, and 15 min in a high-pressure processor ISO-Lab S-FL-100-250-09-W (Stansted Fluid Power Ltd., UK). Pressure treatment above 300 MPa resulted in a significant (p is less than 0.05) decrease of total plate count. However, the studied pressurizing time had no significant effect on microbial lethality at the same pressure applied. Other important parameters such as water activity, moisture, and pH were determined as they directly affect microorganism growth and resistance to pressure. A slight increase in pork pH was observed with increased pressure. No significant changes in water activity and moisture content were observed as a result of high pressure treatment. For future researches it would be important to evaluate the dynamics of microbial growth during storing as part of cells after pressure treatment are injured and not eliminated immediately; therefore, microbial count may further decrease during cold storage.

High-pressure processing (HPP) is typically used for the microorganism inactivation, which provides safety and prolonged shelf life of meat and meat products. However, for consumers along with safety, it is important to have good sensory properties, which is a combination of tender and juicy meat with an intense meat flavour. These attributes may change because of the high pressure processing; therefore, the aim of the study was to evaluate the effect of HPP on sensory and physical attributes of pork upon processing at 300 and 600 MPa at room temperature for 1 and 15 min. After HPP the processed pork samples were cooked within the package in a water bath. Colour of cooked pork did not differ among samples. Moisture content of samples decreased with the increased processing time. Sensory evaluation revealed that HPP treatment did not influence the colour and flavour of cooked pork irrespective of treatment parameters applied in the current study. The panellists indicated that increased pressure made pork samples drier and tougher, thus changing such sensory attributes as juiciness and chewiness, which are important for meat palatability. The correlation found between chewiness determined by sensory analysis and toughness determined by Warner-Bratzler shear device suggested this instrumental method as a better tool when compared to the instrumental texture profile analysis (TPA).

Tryptophan is a precursor for the production of skatole and indole in the large intestine of pigs. Accumulation of these compounds in adipose tissue causes on objectionable odour in meat from entire male pigs. Potential market impact illustrates the importance in developing an accurate method of determining skatole and indole content in adipose tissue. In the present study, a method is described for determination of skatole and indole concentrations by liquid chromatography combined with mass spectrometry (LC-MS) using atmospheric pressure chemical ionization (APCI). The optimization of chromatographic and APCI conditions is reported. This method showed excellent linearity over the concentration range tested (from 10 to 1000 ng mlE-1 of liquefied fat for both skatole and indole).