Street Pork Vendors' Hygiene and Safety Practices and Their Determinants in the Cape Metropole District, South Africa

South Africa's rapid urbanization and high unemployment rates pushed people into street food vending as an alternative source of livelihood. Hygiene and food safety have become a concern under these circumstances owing to foodborne illnesses and associated deaths. A survey tool with 38 structured questions was administered to 172 to assess pork vendors' hygiene and safety practices and identify their determinants in five low-income high-density suburbs of the Cape Metropole District, South Africa. Overall, vendors washed their hands before and after handling meat (66% of respondents) and cleaned the working area daily (51%), pork storage area daily (60%), and utensils and equipment before and after use (36%) with most of them using detergents as the main cleaning agent (70%). A quarter of the interviewed vendors experienced meat spoilage during storage, and 80% had no training in hygiene and safe food handling. The marginal effects of logistic regression findings showed that vending income increased the vendor's probability to wash hands, and clean vending stalls, storage areas, utensils, and equipment. The likelihood of vendors cleaning pork storage areas, utensils, and equipment increased with the increase in female participants. The likelihood of hand washing and vending stall cleaning increased by 1% for each extra year of schooling. Strategies aimed at improving meat hygiene and safety practices of vendors in the surveyed areas should target vulnerable groups, especially less educated females depending solely on vending income.

Effect of sex (ram or wether) and short duration, high volt electrical stimulation on tenderisation of Longissimus thoracis et lumborum and Semimembranosus muscles derived from Boer Goat and large frame Indigenous Veld Goat

This study determined whether castration and electrical stimulation (ES) influenced chevon tenderness and related physiological characteristics in Boer Goat (BG; n = 36; 21 bucks and 15 wethers) and large frame Indigenous Veld Goat (IVG; n = 41; 21 bucks and 20 wethers). Half of buck and wether carcasses were ES (20s, 400 Volts peak, 5 ms pulses at 15 pulses/s) 10 min post-mortem. Dressed carcasses were chilled (4 °C within 1-h post-mortem). pH and temperature decline, % drip loss, sarcomere length (SL), myofibril fragmentation length (MFL; 1- and 4-days post-mortem), Calpain-1, -2 and calpastatin activities (1- and 24-h), Warner-Bratzler shear force (WBSF; 1-day post-mortem) and sensory attributes (tenderness and juiciness; 4-days post-mortem) were measured on Longissimus thoracis et lumborum (LTL) and Semimembranosus (SM) muscles. ES carcasses had significantly lower pH irrespective of sex or breed. Buck LTL and SM were less tender (P ≤ 0.05) supported by longer MFL and higher calpastatin activity (P < 0.05), than wether muscles. ES LTL were more tender (WBSF and sensory) (P ≤ 0.001) while ES SM were less affected (P = 0.055). ES caused lower Calpain-1 activity in the LTL. SL do not support cold shortening and calpastatin played a major role in the tenderisation of chevon early post-mortem. A longer ageing period is recommended for goat meat in general to achieve acceptable levels of tenderness.

Quality and safety of pork sold in the informal urban street markets of the Cape Metropole, South Africa

Pork in the informal market significantly contributes to food, nutrition and income security in low-income countries' urban areas but is a safety concern to value chain actors and public authorities due to potential contamination by pathogens. To evaluate the physicochemical quality, microbial and oxidative profiles of pork sold from the informal urban street market, 50 samples were collected from 40 street vendors and 10 supermarkets in five different low-income, high-density suburbs in the Cape Metropole District, South Africa. Results showed no differences (P > 0.05) in pH, colour, proximate attributes (except for lipid content), antioxidant activity, lipid oxidation, and Escherichia coli counts in pork collected from the formal and informal markets, and open-air and enclosed market stalls. Lipid content, Enterobacteriaceae, and total bacterial counts of pork collected from the informal market were higher (P ≤ 0.05) than those from the formal market. Positive cases of Listeria monocytogenes (6-8%) and Salmonella spp. (4%) were reported for pork sampled in the informal market, especially in open-air stalls. It was concluded that higher levels of microbial contamination in the informal market, particularly in open-air stalls compared to the formal market require constant monitoring, provision of appropriate market infrastructure, and hygiene behaviour change of vendors to ensure pork safety.

Fatty acid and oxidative shelf-life profiles of meat from lambs fed finisher diets containing Acacia mearnsii leaf-meal

Five diets containing Acacia mearnsii leaf-meal (AMLM; 0, 50, 100, 150 and 200 g/kg DM) substituted for Triticum aestivum bran were fed to lambs for 42 days. The effect of diet and retail display period on meat fatty acid (FA) composition (day 1); colour, antioxidant activity, myoglobin and lipid oxidation (day 1, 3, 5, 7 and 9); protein oxidation (1, 3 and 7 d) and instrumental tenderness (day 1, 5 and 10) were evaluated. Dietary AMLM linearly decreased (P ≤ 0.05) individual (14:0, 16:0, 18:0) and total saturated FA and increased (P ≤ 0.05) trans(t)-monounsaturated FA (MUFA) mainly t10/t11-18:1, individual and total conjugated linoleic acids, n-3 and n-6 polyunsaturated FA (PUFA) contents. The contents of cis(c)-MUFA, mainly c9-18:1, exhibited a quadratic response reaching a minimum at 50 g/kg AMLM (P ≤ 0.05). Meat antioxidant on day 9 was higher (P ≤ 0.05) for diets containing ≥100 g/kg DM AMLM compared to the other diet × retail display period interactions. Relative to the other interactions, meat redness values were lowest on day 7 and 9 for AMLM diets containing ≥150 g/kg DM (P ≤ 0.05). Dietary addition of AMLM increased (P ≤ 0.05) meat lightness and oxymyoglobin, and reduced (P ≤ 0.05) TBARS and instrumental tenderness values. However, oxymyoglobin values declined (P ≤ 0.05) over the retail display period, while lightness, metmyoglobin, TBARS and carbonyls increased (P ≤ 0.05). Results indicate that AMLM up to 200 g/kg DM in lamb finisher diets, improves meat fatty acid composition, tenderness, and lipid shelf-life.

A South African beef quality survey

In this study a survey of various meat quality characteristics of beef loin cuts was conducted in the City of Tshwane Metropolitan Municipality (Gauteng Province of South Africa) to determine the variation and consistency of beef quality of products purchased over time. Four hundred and twenty beef loin samples were collected on 20 occasions over 308 days from 13 outlets of 2 supplier types (butcher and supermarket). Packaging type, label information and price were considered for the evaluation of meat tenderness, colour, cooking loss, tissue composition and steak thickness. The results demonstrate that large variation in characteristics relevant to consumers' choice and satisfaction among and within different products sold as porterhouse steak in South Africa. In particular, muscle tenderness varied (P < 0.0001) across the 20 products and also showed significant inconsistency over the 20 purchasing events for certain products.

An Exploratory Study into the Influence of Sex on Body Measurements, Carcass Weights and Meat Yields of Giraffe (Giraffa camelopardalis angolensis)

Various body measurements and commercial carcass yields of relatively young (2½–6 yrs old) giraffe (Giraffa camelopardalis angolensis) were investigated to quantify the effect of sex there upon. Eight male and eight female giraffe were culled by standard practice in Namibia, where body and horn measurements were taken, before the carcasses were dressed. There were no significant differences between the mean dead weights of the two sexes (bulls = 691.1 kg; cows = 636.5 kg; p = 0.096), the only body measurements found to differ significantly were those of the forelegs, with the shoulder to hoof (p = 0.046) and the knee to hoof (p = 0.025) both being significantly longer in the bulls. The horn measurements were all found to be significantly larger in the bulls than the cows even at this young age. The neck weight as a percentage of the carcass weight was found to be significantly heavier for the bulls compared to the cows, however, the back percentage values were significantly heavier in the cows than the bulls. There was a strong positive correlation between the body weight and most of the body lengths, as well as between most of the individual body measurements. The giraffe used had an average age of 3.7 years old, and had therefore not yet reached their growth plateau, which may be why sex had no influence on most of the body measurements recorded.

Nutrient retention values and cooking yield factors for three South African lamb and mutton cuts

BACKGROUND

Nutrient content of raw and cooked foods is important for formulation of healthy diets. The retention of nutrients during cooking can be influenced by various factors, including animal age, carcass characteristics and cooking method, and these factors are often unique to specific countries. Here the effects of animal age (lamb and mutton) and carcass cut (shoulder, loin and leg) combined with cooking method (moist heat and dry heat) on yield and nutrient retention of selected nutrients of South African sheep carcasses were studied.

RESULTS

Cooking yields and moisture retention were lower for lamb loin but higher for lamb leg. Energy and fat retention were higher for all cuts of mutton compared with lamb, while higher retention values for cholesterol were recorded for lamb. Mutton retained more iron (P = 0.10) and zinc and also more vitamin B₂ , B₆ and B₁₂ than lamb. Shoulder cooked according to moist heat cooking method retained more magnesium, potassium and sodium.

CONCLUSION

Incorporating these retention and yield values into the South African Medical Research Council's Food Composition Tables provides a reliable reference to all concerned with nutrient content of food. It will also guide practitioners and primary industry to adjust animal production aimed at optimum nutrient content to specific diets. © 2017 Society of Chemical Industry.

The effects of animal age, feeding regime and a dietary beta-agonist on tenderness of three beef muscles

BACKGROUND

Animal age as determined by number of permanent incisors (p. i.) is used in classification of beef carcasses to describe expected meat tenderness. However, animals differing in age are reared under different production systems (pasture or feedlot). In addition to age, other factors associated with particular production systems may also influence the palatability of meat. Therefore, the effects of age combined with feeding regime and the supplementation of a beta-agonist (zilpaterol) on the tenderness of M. longissimus lumborum (LL), M. semitendinosus (ST) and M. biceps femoris (BF) muscles were investigated.

RESULTS

Tenderness of LL cuts was least affected by age but zilpaterol significantly decreased tenderness and ageing potential. Tenderness of high-collagen cuts (BF and ST) was negatively affected by age due to reduced collagen solubility. The effect of zilpaterol on these cuts was less significant and BF and ST cuts of the grain-fed A-age animals (0 p. i.) supplemented with zilpaterol (AZ) were more tender than the same cuts of grass-fed animals with 1-2 p. i. (AB-age) and grass-fed animals with 3-6 p. i. (B-age) according to Warner-Bratzler shear force (WBSF) and sensory analysis for tenderness.

CONCLUSION

This study indicates that beta-agonists may influence variation in tenderness within an age class more than age or feeding regime. © 2016 Society of Chemical Industry.

Growth performance, hematology, and meat quality characteristics of Mutton Merino lambs fed canola-based diets

A 56-day feeding trial was carried out to evaluate the effect of feeding canola meal (CM) on growth performance, hematology, and meat quality parameters of lambs. Twenty lambs with an average body weight of 23 ± 2.64 kg were randomly assigned to five dietary treatments and fed in individual cages for 56 days. The soya bean meal (SBM) in the control ration was replaced with canola meal at 0 (CM0), 25 (CM25), 50 (CM50), 75 (CM75), and 100 % (CM100) inclusion levels. Average daily weight gain (ADWG) and average daily feed intake (ADFI) were significantly higher in the CM25 and CM50, respectively. Feed conversion ratio (FCR) (3.09-3.41) and slaughter weight (SLW) (33.2-34.7 kg) were, however, similar among the treatment groups. Diet had no effect on carcass length (78.7-83.7 cm) and ultimate meat pH (pHu) (5.70-5.81). Nevertheless, hot carcass weight (HCW) (16.5-18.7 kg) and cold carcass weight (CCW) (16.2-18.2 kg) were higher (P < 0.05) in the CM0 and CM50 treatment groups. The shear force measurements (1.67-2.17 kg) differed (P < 0.05) across treatments. There was no dietary effect on the lightness (L*) (33.5-35.8), redness (a*) (11.35-12.7), and yellowness (b*) (13.4-14.8) of meat. In conclusion, CM can completely replace SBM in lamb diets without any negative effects on growth performance, general health, and meat quality of Mutton Merino lambs.

Minimal electrical stimulation is effective in low stressed and well fed cattle

Four groups of carcasses of eighty grain fed low stressed steers (~12 months old, 240 kg carcass weight) received no stimulation or had low voltage stimulation for 15, 45 and 90 s. M. longissimus was aged for 2 and 14 days at 2 °C. Shear force, sarcomere length, water holding capacity, purge, muscle fibre detachment, sarcomere breaks and colour shelf life over 7 days was measured. Both 45 s and 90 s stimulated samples completed rigor above 35 °C and 15s stimulated and non-stimulated samples below 35 °C. The greatest muscle fibre detachment occurred for 15s stimulated samples which were the most tender at all times with non-stimulated samples toughest at 2 days of ageing and all samples being tender at 14 days of ageing. The 45 and 90 s stimulated samples consistently exhibited a brighter red colour at 2 days of ageing with no differences in colour intensity for the samples aged 14 days.

Effect of South African beef production systems on post-mortem muscle energy status and meat quality

Post-slaughter muscle energy metabolism meat colour of South African production systems were compared; steers (n=182) of Nguni, Simmental Brahman crossbreds were reared on pasture until A-, AB-, or B-age, in feedlot until A-AB-age. After exsanguination carcasses were electrically stimulated (400 V for 15 s). M. longissimus dorsi muscle energy samples were taken at 1, 2, 4 and 20 h. Post-mortem samples for meat quality studies were taken at 1, 7 and 14 days post-mortem. Production systems affected muscle glycogen, glucose, glucose-6-P, lactic acid, ATP, creatine-P glycolytic potential (P<0.05), with the muscles of feedlot carcasses having a faster glycolysis rate than pasture carcasses. Energy metabolites correlated (0.4<r<0.9) with meat colour (CIE, L*a*b*), (0.3<r>0.5) water holding capacity, drip loss, and Warner Bratzler shear force. Muscle energy only affected muscle contraction of the A-age-pasture system (shortest sarcomere length of 1.66 μm vs 1.75 μm highest WBS of 6 kg vs 5 kg 7 days post-mortem).

Effect of age and cut on cooking loss, juiciness and flavour of South African beef

The juiciness and flavour characteristics of 15 aged primal beef cuts of electrically stimulated carcasses, from three different age groups, were assessed (n=61). Cooking losses were determined and proximate analyses (moisture, fat, nitrogen and ash) were performed. Tender cuts were cooked by a dry heat method, and less tender cuts were cooked by moist heat methods. A trained panel (n=10) evaluated sensory quality characteristics including initial and sustained juiciness, aroma and flavour. Flavour intensity was the biggest discriminant between the three age groups and declined with an increase in age. Initial impression of juiciness decreased with increased age of the animal and cooking losses increased nonlinearly with age, irrespective of the muscle. In contrast sustained juiciness increased with increased age. Cuts cooked according to a dry heat cooking method were reported juicier (both initial and sustained) than those cooked by moist heat methods.

Meat quality of Nguni steers supplemented with Acacia karroo leaf-meal

The objective of the study was to determine the meat quality of Nguni steers supplemented with Acacia karroo leaf-meal. Thirty 19-month old steers were randomly assigned to A. karroo leaf-meal (AK), sunflower cake (SF) and a control (CN) diets. Steers on the AK and SF diets were given an additional 150 g of protein per day for 60 days. The steers were slaughtered at 21 months and the m.longissimus thoracis et lumborum was sampled for meat quality measurements. Steers that received SF diet had lighter-coloured (L*) (P<0.05) meat than those on AK and CN diets. The highest redness (a*) (17.3+/-0.29) values were recorded in steers supplemented with AK compared to those that received SF and CN diets. Diet had no effect on pH, drip loss, water holding capacity, sarcomere length, muscle bundle areas, myofibrillar fragment length, Warner-Bratzler shear force and cholesterol values. Steers supplemented with AK (22.4+/-0.08%) and SF (22.5+/-0.08%) had higher (P<0.05) meat protein content than those on the CN (20.2+/-0.08%) diet. Highest muscle fibre area (3472.6+/-119.51 microm(2)), fat content (1.2+/-0.11%) and cooking loss (25.2+/-0.73%) of meat aged for 2 days were recorded in steers given the SF diet compared to those on the AK and CN diets. Supplementing Nguni cattle with A. karroo leaf-meal produced beef of comparable quality to natural pasture alone but with a fresher appearance and higher protein content.

The beef tenderness model

In Phase1 of this study, three breed types (Simmentaler-, Brahman- and Nguni bulls; n = 60 each) were grain-fed and slaughtered at 12 months of age (A-age, fat-class 2). Feed was withdrawn for either three hours or 24 hours pre-slaughter. Within each feed withdrawal group, three electrical stimulation (ES) treatments were applied, viz. ES for 15 seconds, 120 seconds or no stimulation. In Phase 2, the effects of animal age and feeding regime were investigated using of A-age (feedlot and pasture), AB-age (feedlot and pasture) and B-age (pasture) animals. All carcasses were electrically stimulated for 15 seconds. Longer feed withdrawal increased dark-firm-dry (DFD) meat occurrence (pHu >6) in the Nguni and Simmentaler-cross. Brahman-cross longissimus (LL) tended to be more tender with paler colour and higher drip loss when 120 ES was applied. Longer feed withdrawal recorded higher Warner Bratzler shear force (WBSF) than three hour feed withdrawal. However, ES neutralized the effect of stress on tenderness. On average the AB-age feedlot animals produced the most tender LL followed by the B-age pasture and A-age feedlot which was similar to the AB-age pasture. A-age pasture animals produced the least tender LL steaks. The calpain proteolytic system played a pivotal role in determining the ultimate meat tenderness and although connective tissue becomes less soluble in older animals it did not play the determinant role in tenderness in this study. The intramuscular fat (< 3%) played an important role in the tenderness outcome of Nguni LL which marbled well at AB-age.Keywords: Meat tenderness, pH and temperature decline profile, pre- and post-slaughter conditions, production systems

Visual evaluation of beef tenderness by using surface structural observations and its relationship to meat colour

The study describes the relationship between visual and instrumental measurements for colour and tenderness between five South African beef breeds: Bos indicus (Brahman), Sanga type (Nguni), British Bos taurus (Angus), European Bos taurus (Charolais) and the composite (Bonsmara). Ten animals per genotype were used (total = 50). The carcasses were split and the right sides were electrically stimulated, while the left sides were not stimulated. Steaks were aged until three days post mortem on polystyrene plates and until 9, 14 and 20 days post mortem in vacuum bags. The steaks were evaluated by visual analysis for colour, marbling, fibre separation, surface texture and structure integrity by a 10-member trained panel. Colour was also measured by the CIE L*, a*, b* system using a Minolta meter, and tenderness was measured by means of Warner-Bratzler shear force. High negative correlations were observed between the visual colour and L* (r = −0.809), b* (r = −0.698) and high positive correlations were observed between the visual colour and hue (r = 0.797). There were also negative correlations between shear force and structure integrity (r = −0.410) and fibre separation (r = −0.401). Very low negative correlations were observed between colour and shear force (r = −0.242). Therefore, although it may be possible to judge meat colour by visual analysis, it does not appear possible to predict tenderness by colour judgment. There is potential for an experienced eye to predict tenderness by observing visual structural properties such as fibre separation and structural integrity.Keywords: Meat colour and tenderness, tenderness prediction, trained visual panel, visual analysis

Proteomics approach as a new way to predict tenderness as compared to the classical South African Beef Carcass Classification System

The current South African Beef Carcass Classification System classifies carcasses using physical attributes such as age, fatness code and the conformation of the carcass as the only indicator of tenderness, implying that optimal tender meat is obtained from carcasses from animals with no permanent teeth. Research shows that if we take modern technologies (use of beta-agonists, growth hormones and electrical stimulation amongst others) into account, this is not necessarily true. In this study m. longissimus lumborum samples were collected from Nguni breed animals, snap frozen and stored at −80 ºC for further use in search of protein markers that can be used to predict tenderness in a non-invasive manner. Proteins were extracted in 1 mL TES buffer, isoelectrically focused on strips (pH 5 - 7) and separated by 2D SDS PAGE, stained with coomassie brilliant blue G250) and imaged by a Chemi-doc Mp imager. The results showed differences in protein expression, e.g. some proteins are present at 1 hour post mortem (Day 0) but absent at 3 days post mortem (Day 3). Other proteins showed an increase in expression as ageing progresses. These proteins correlated with myofibril fragments and Warner Bratzler changes which were measured. There are several factors that may be responsible for these changes in differential expression during ageing such as proteolytic action (i.e. calpains and calpastatin system, cathepsins) or maybe apoptosis. The proteins in the profiles of Nguni breed animals which showed differential expression in response to ageing are still to be determined.Keywords: Nguni breed, protein markers for tenderness, two dimensional gel electrophoresis (2D SDS PAGE)

Sources of variation in quality of South African beef: Case studies in relation to the red meat classification system

The South African classification system describes beef carcasses in regard to visual fat cover, conformation and age by dentition. Animal age provides a fairly accurate description of expected eating quality in regard to tenderness in an industry where other sources of variation in tenderness are limited. Since deregulation in the beef industry in the 90s many changes have occurred in all parts of the value chain. This paper presents a number of case studies that focussed on the sources of variation in meat quality, but in particular on sources of changes in meat tenderness over the past two decades. These sources include feeding regime, the use of beta agonists, post mortem ageing and electrical stimulation. In some studies these factors are integrated with age or interactions among two or more of these factors are investigated.Keywords: Age, beef, classification, dentition, grading