The impact of frequent load-shedding on milk quality in KwaZulu-Natal, South Africa: A review

Abstract

Frequent power outages in South Africa, particularly in KwaZulu-Natal (KZN), disrupt critical dairy operations such as milking, cooling, feeding, and pasteurisation, thereby compromising the microbial, physical, and chemical quality of raw milk. This review evaluates the impact of load-shedding on milk quality in KZN, focusing on microbial growth dynamics, temperature fluctuations, and changes in milk composition. Cow’s milk is highly sensitive to handling and storage conditions, and an unstable electricity supply accelerates spoilage and reduces the effectiveness of pasteurisation. This review also considers the structure of the regional dairy industry and highlights challenges such as high electricity costs, narrow profit margins, and competition from subsidised imports. Temperature and pH are identified as key indicators of spoilage during power interruptions. Evidence shows that load-shedding events are associated with elevated microbial counts, reduced pH, and altered sensory attributes, ultimately threatening milk safety and farmer profitability. Effective mitigation strategies are emerging, including the use of backup generators, solar power, adjusted milking schedules, and improved pasteurisation practices to reduce microbial risks under unstable power conditions. By integrating technical, economic, and management perspectives, this review provides insights into the resilience of KZN’s dairy sector. It emphasises the need for on-farm interventions and supportive policy frameworks to safeguard milk quality and strengthen food security in South Africa. (Submitted 10 July 2025; Accepted 27 October 2025; Published 27 April 2026)