Effect of feeding histidine and β-alanine on carnosine concentration, growth performance, and meat quality of broiler chickens

The high growth rates of modern broiler breeds increased the risk for novel breast muscle myopathies as serious quality issue, relevant for the industry. In affected muscles, a depletion of the dipeptides carnosine and anserine was reported. Therefore, this study was performed to test whether a supplementation of the precursors histidine and β-alanine, alone or in combination can increase the dipeptide content in the breast muscle and improve meat quality.

Ross 308 broiler chickens were supplemented with 3 different histidine:lysine ratios (0.44, 0.54, 0.64) of standardized ileal digestible amino acids (SID) combined with 0 or 0.5% β-alanine in total. The birds’ performance was recorded at different ages: birds were slaughtered in 2 batches after 33 and 53 d of life. Meat quality was tested at different time points after slaughter on breast fillets stored aerobically. The concentration of the dipeptides and amino acids in blood plasma and muscle tissue was tested postmortem at 35 and 54 d. All performance and meat quality data, as well as peptide and amino acid concentrations, of the 2 × 2 × 3 randomized block design were analyzed separately for the influence of both supplements and for slaughter age. Moreover, the influence of storage time was analyzed separately for meat quality parameters. At both slaughter ages, lesser feed intake (P ≤ 0.005) and breast yield (P ≤ 0.05) were observed in the birds receiving β-alanine. A greater SID histidine:lysine ratio increased the carnosine concentrations in blood plasma (P < 0.001) and in skeletal muscle (P < 0.001), whereas β-alanine increased carnosine in plasma at 35 d only (P = 0.004). Anserine was increased in plasma and muscle of older birds (P = 0.003), whereas carnosine was reduced in muscle tissue (P < 0.001). The main impact on meat quality parameters was seen for the age of the birds and storage time of the fillets. In conclusion, the supplementation of histidine increased carnosine in breast muscle but both supplements showed only minor effects on meat quality.

Potential of the polymer poly-[2-(tert-butylamino) methylstyrene] as antimicrobial packaging material for meat products

AIMS

The objective of the study was to investigate the antimicrobial potential of a new SAM(®) polymer poly(TBAMS) as packaging material for meat products.

METHODS AND RESULTS

The influence of temperature, time and product factors on the antimicrobial activity of poly(TBAMS) against different bacteria was determined using a modified test method based on the Japanese Industrial Standard 2801:2000. Results showed a significant reduction in bacterial counts on poly(TBAMS) compared with the reference material of several meat-specific micro-organisms after 24 h at 7°C. Bacterial counts of Staphylococcus aureus, Listeria monocytogenes, Lactobacillus spp., Brochothrix thermosphacta and Escherichia coli were reduced by >4·0 log10  units. Pseudomonas fluorescens was less sensitive to poly(TBAMS) within 24 h between 2 and 7°C. Prolonging the storage time to 48 h, however, resulted in an increased reduction rate. Furthermore, antimicrobial activity was also observed if meat components in the form of meat extract, meat juice or bovine serum albumin protein were present. Antimicrobial activity was also achieved if inoculated with mixed cultures.

CONCLUSIONS

Poly(TBAMS) showed antimicrobial properties under conditions typical for meat supply chains.

SIGNIFICANCE AND IMPACT OF THE STUDY

Poly(TBAMS) bears a high potential to increase safety and shelf life of meat products.

Ainsliaolide D: a new sesquiterpene lactone from Ainsliaea pertyoides

Ainsliaolide D, a new guaiane-type sesquiterpene lactone, was isolated from the roots of Ainsliaea pertyoides Fr. var. albotomentosa Beauverd. Its structure was determined based on spectral data.

Study on the antimicrobial effect of silver-containing inner liners in refrigerators

AIMS

To investigate the effect of silver-based antimicrobial material incorporated in the inner liners of refrigerators on food safety and quality.

METHODS AND RESULTS

In the first stage, the bactericidal effect was tested in the laboratory. Silver-containing samples and control plates were inoculated with different bacterial suspensions and stored at various temperatures. After defined storage periods the bacterial reduction was calculated by comparing viable cell count on reference plates and on silver-containing plates. The reduction caused by the silver-containing material varied between 1.0 and 5.9 log(10) units, depending on bacterial strain, incubation time and temperature. In the second stage, food storage experiments have been carried out. Thus, perishable foods were stored in coated and untreated refrigerators. After certain time periods the products were analysed for their sensorial and microbiological characteristics. A clear drop in viable counts both on the refrigerator wall and on the food was demonstrated using the silver-based antimicrobial material.

CONCLUSIONS

Silver prevents refrigerators from being a hot spot for contaminants that could be transferred upon contact with food.

SIGNIFICANCE AND IMPACT OF THE STUDY

This study provides original results regarding the antimicrobial activity of silver-containing refrigerator surfaces.