Sensory attributes of chicken meat in relation to microbial and physicochemical characteristics

Abstract

In line with global trends, chicken meat is the most consumed source of animal protein in South Africa. Raw chicken meat is frequently contaminated with Salmonella spp. and Campylobacter spp., and is highly susceptible to bacterial spoilage if improperly handled. Although the chicken industry is primarily responsible for the quality and safety of chicken meat, consumers have an active role to play as they represent the final line of defence against the occurrence of foodborne illnesses and food waste. This study was undertaken to investigate and assess the practices, knowledge and perceptions of a group of South African consumers with respect to handling raw chicken meat, and to identify the associated risks to meat safety and quality. Subsequently, the odour and appearance attributes of raw chicken meat during refrigerated storage under aerobic packaging were characterised and the relationship with microbial and physicochemical quality changes was established. Finally, the link between consumers’ perceptions, handling practices and sensory, microbial and physicochemical characteristics of chicken meat was elucidated. A web-based cross-sectional consumer survey (n = 863) was conducted using convenience sampling. The survey questionnaire collected information on consumers’ handling practices, knowledge of temperature related factors affecting the safety and quality of chicken meat and perceptions on intrinsic and extrinsic attributes as indicators of the safety and quality of chicken meat. Furthermore, raw chicken legs obtained from a commercial poultry processing plant were stored at 4 °C and microbiological (total viable counts, Pseudomonas spp., Enterobacteriaceae and lactic acid bacteria), physicochemical (pH and instrumental colour) and descriptive sensory analyses (odour and appearance) were conducted during storage for 14 days. Overall, only 38% of the surveyed respondents were rated as following good practices and 28% as having good knowledge about temperature related factors affecting the safety and quality of chicken meat. Gaps in handling practices and knowledge that potentially result in breaking of the chicken meat cold chain, the transmission of pathogenic bacteria and cross-contamination were identified. Moreover, smell, use-by date, sell-by date and colour were perceived by a large majority of respondents as highly important attributes when judging chicken safety and quality at point of purchase and the home. Smell was considered significantly more important than colour. Extrinsic attributes such as absence of brine use and growth-promoting hormones in chicken feed were also considered as relatively important. The storage study revealed that odour attributes of chicken meat (fresh chicken, bloody, pungent, fishy, rotten egg, ammonia-like and intense overall odour) changed at a faster rate than colour (L* and saturation) and appearance attributes (creamy skin, pink flesh, green/blue colouration and slimy). Odour attributes were also highly correlated (r > 0.8) with microbial growth. On the other hand, no correlations were found between colour and appearance attributes and microbial growth in chicken meat. Consumers’ handling practices and knowledge levels suggest that there is potential for unacceptable growth of spoilage and pathogenic bacteria in chicken meat. Additionally, the smell of chicken meat is perceived as a more important attribute than colour probably due to the significant differences in the rate of deterioration and relation with microbial growth during storage. The results from this study reflect a need for educational interventions focused on microbial risks in chicken meat and the consequences of mishandling on safety and quality, guidelines to prevent temperature abuse, the transmission of bacteria and cross-contamination.