Liking, salt taste perception and use of table salt when consuming reduced-salt chicken stews in light of South Africa's new salt regulations.

This study investigated the impact of salt reduction on liking, salt taste perception, and use of table salt when consuming chicken stew in light of South Africa's new salt recommendations. In total, 432 South-African consumers (aged 35.2 ± 12.3 years) consumed a full portion of a chicken stew meal once at a central location. Four stock cube powders varying in salt content were used to prepare chicken stews: 1) no reduction - 2013 Na level; regular salt level as currently available on the South African market (24473 mg Na/100 g), 2) salt reduction smaller than 2016 level, i.e. 10%-reduced (22025 mg Na/100 g), 3) 2016 salt level, as per regulatory prescriptions (18000 mg Na/100 g), 4) 2019 salt level, as per regulatory prescriptions (13000 mg Na/100 g). Consumers were randomly allocated to consume one of the four meals. Liking, salt taste perception, and use of table salt and pepper were measured. Chicken stews prepared with reduced-salt stock powders were equally well-liked as chicken stews with the current salt level. Moreover, a gradual reduction of the salt in the chicken stews resulted in a reduced salt intake, up to an average of 19% for the total group compared to the benchmark 2013 Na level stew. However, 19% of consumers compensated by adding salt back to full compensation in some cases. More salt was added with increased reductions of salt in the meals, even to the point of full compensation. Further investigation into the impacts of nutrition communication and education about salt reduction on salt taste perception and use is needed. This research provides new consumer insights on salt use and emphasises the need for consumer-focused behaviour change approaches, in addition to reformulation of products.

Effect of dietary conjugated linoleic acid supplementation on the technological quality of backfat of pigs.

Pigs were fed diets containing 0, 0.25, 0.5 and 1% conjugated linoleic acid (CLA). Compared to controls, backfat from CLA fed pigs was firmer and extracted lipid contained increasing amounts of CLA, but a ±11% overall decrease in unsaturated fatty acids and a ±5% overall increase in each of C16:0 and C18:0 saturated fatty acids were noted. This resulted in a change in the melting properties of fat. The onset setting temperature increased from ±14°C to ±18°C for lipid of backfat of pigs from the 0.25 and 0.5% CLA supplementation groups, and to ±26°C for lipid from the 1% CLA supplementation group. The final melting temperatures increased from ±37°C to ±43°C and ±45°C, respectively. The presence of ß'-crystals of C18:0-C16:0-C18:1c9 triacylglycerides in fat from CLA fed pigs and ß-crystals in fat from 1% CLA fed pigs was observed. Fatty acid and melting point results explained the improvement in the technological quality of backfat as a result of dietary CLA supplementation.

Survival of Escherichia coli o157:h7 co-cultured with different levels of pseudomonas fluorescens and lactobacillus plantarum on fresh beef.

The purpose of this study was to investigate the effect of different levels of Pseudomonas fluorescens (10(2) and 10(6) log10 cfu/ml) and Lactobacillus plantarum (10(2) and 10(4) log10 cfu/ml) on the growth of Escherichia coli O157:H7 on beef loins. Beef loins inoculated with E. coli O157:H7 and P. fluorescens were aerobically stored for 7 days at 4 ºC, while those inoculated with E. coli O157:H7 and L. plantarum were vacuum packaged and stored for 8 weeks at 4 ºC. Aerobic Plate Counts (APC), E. coli O157:H7 and either P. fluorescens or L. plantarum counts were determined at different storage intervals. For the aerobically packaged beef loins, E. coli O157:H7 was detected throughout the 7 day storage period regardless of the P. fluorescens level in the inoculum. For the vacuum packaged beef loins, similar inoculum levels of E. coli O157:H7 and L. plantarum allowed E. coli O157:H7 to survive until week 5 of storage, while a higher inoculum level of L. plantarum inhibited E. coli O157:H7 from week 3. Once fresh beef has been contaminated with E. coli O157:H7, the level of P. fluorescens in the background flora does not inhibit its survival and growth. However, under vacuum storage, the application of L. plantarum as a biopreservative inhibits the survival of E. coli O157:H7 on beef. The higher the level of L. plantarum in the system, the earlier the onset of the inhibition. Farmers and abattoirs have to strengthen preventive strategies to eliminate contamination of beef carcasses with E. coli O157:H7.

Meat quality of designated South African indigenous goat and sheep breeds.

Carcass composition, proximate meat composition, fatty acid composition and sensory characteristics of two breeds of goats, Indigenous (n=12) and Boer goats (n=12), and two breeds of sheep, Damara (n=12) and Dorper (n=12), on extensive pasture-grazing, were analysed. The right side of each carcass was processed into wholesale cuts and dissected into subcutaneous fat, meat and bone. Meat and fat were minced together and sampled for proximate analysis as well as fatty acid profiles. The remaining minced meat was formed into meat patties, which were cooked for descriptive sensory evaluation of aroma, tenderness, juiciness and flavour characteristics by a trained panel. Goat and sheep breeds had different meat qualities. The composition and properties of subcutaneous and intramuscular fat contributed to the differences in meat quality observed within and between the species studied. Goats had proportionally smaller carcasses. Sheep yielded more dissectable fat and lean and less bone as a percentage of carcass weight than goat breeds, although the proportional lean content per cut of Boer goats was comparable to that of sheep. The percentage of bone was highest for Indigenous goats. Concentrations of saturated fatty acids were higher in goats compared to sheep. Sheep patties were more tender, juicy, greasy and less chewy compared to goat patties. The species related goaty and muttony flavour were clearly distinguishable. It is recommended that goats should be valued as a different species compared to sheep.

Consumer acceptability of dark, firm and dry (DFD) and normal pH beef steaks.

The sensory attributes of dark, firm and dry (DFD) and normal pH beef, both raw and fried, were evaluated and compared by a consumer panel (n=64). Consumer sensory evaluations indicated that the general appearance (P<0.05), colour (P<0.001) and acceptability (P<0.01) of raw normal pH steaks were preferred to those of raw DFD steaks. Twice as many panellists preferred the raw normal pH than raw DFD steaks because of the more attractive red colour, compared to the almost black colour of raw DFD steaks. No significant differences were found between the hedonic ratings of the sensory attributes of fried normal pH and fried DFD steaks. It was expected but not confirmed that consumers would find the tenderness of the DFD steaks more acceptable compared to the normal pH steaks. However, when forced to choose, female consumers significantly preferred fried normal pH steaks to fried DFD steaks, presumably because of a better flavour and more acceptable colour.

Temporal aspects related to the perception of skatole and androstenone, the major boar odour compounds.

Pork fat samples from 50 boars slaughtered at a commercial abattoir were analysed for skatole and androstenone concentrations and grouped within a 3×3 matrix representing low, medium and high levels of the odour compounds. A 10 member sensory panel, screened and trained to recognise and quantify skatole and androstenone odour intensities, was used to verify the human perception of boar odour in these pork fat samples immediately after heating (±65°C) and following a cooling period of ten minutes (±25°C). Principal component analysis revealed that the sensory panel differentiated the pork fat samples first and foremost on the basis of the presence or absence of androstenone and/or skatole odours and secondly on the character of the androstenone or skatole odour. Evidence of adaptation towards the odour of skatole was shown by a decreased sensitivity over replicates. Sensory perception of boar odour seems to have a temporal character which can be explained by differences in volatilisation (involving both odourant release and retention) of skatole and androstenone, odour synergism and possibly differences in the properties of the fat matrix of different samples. The results suggest that factors influencing volatilisation of skatole and androstenone should also be considered when predicting sensory responses of boar odour.

Reaction to boar odour by different South African consumer groups.

A consumer sensory study of South African pork consumers (n=300) including equal numbers of males and females and consumers from three ethnic groupings (black, white and coloured consumers) was conducted to determine the effects of gender and ethnicity on consumer reactions towards boar odour compounds. Samples consisted of boar fat with varying concentrations of skatole and androstenone. Each consumer evaluated the odour of seven fat samples. Consumers' liking of pork meat in general had a significant effect on the hedonic rating of the boar odour. The majority of consumers represented in this study would be dissatisfied with pork meat exhibiting detectable levels of skatole. In general, more females compared with males, will also respond more negatively towards samples with detectable levels of androstenone. An apparent liking for samples with medium levels of androstenone (0.5-1 µg/g) was found for some consumers, especially males, and can be partly attributed to the inability of some consumers to smell this compound at these levels or a genuine liking for the odour of androstenone. Significant differences in the sensitivity of consumers from different ethnic groups were found with white females responding more negatively than white males and blacks. Although it was not possible to compare responses directly with the white and black groups, it was found that a higher percentage of coloureds responded negatively to boar odour compounds. Coloured males responded particularly negatively towards samples with detectable skatole, while black males, in general, were found to be more critical than black females. Based on these results it is predicted that the majority of consumers would be less willing to consume pork meat exhibiting detectable levels of boar odour.