Alicyclobacillus. What Is It and Is Your Product at Risk?
Alicyclobacillus is a non-pathogenic spoilage bacteria that silently sours fruit juice products causing economic losses in the fruit juice industry. With the ability to survive commercial pasteurization, Alicyclobacillus causes unpleasant odors in food products that make the products undesirable to consumers. Since Alicyclobacillus in fruit juice does not produce gas or package swelling, it is unnoticeable in products until consumption. (Sourri et al., 2022).
Alicyclobacillus requires considerable attention in the fruit juice industry because of its potential to impact financial losses. According to the Market Data Forecast, the North American Fruit and Vegetable Juice Market size stands at USD 31.1 billion in 2021 with a CAGR of 4.4%, with expectations to reach USD 40.2 billion by 2026. To maintain this growth trajectory, however, the industry must address the challenges of Alicyclobacilius.
What Is Alicyclobacillus and How Does It Grow?
Alicyclobacillus is a type of bacterium with 22 known species. These spore-forming bacteria survive thermal treatment, including pasteurization. They also grow and germinate in low pH or acidic conditions, which allows them to spoil fruit juices with low pH.
The predominant species identified in Alicyclobacillus spoilage is A. acidoterrestris, an aerobic, rod-shaped, endospore-forming, Gram-positive microorganism. Capable of enduring a wide range of pH levels from 2.0 to 7.0 pH, its optimum growth occurs between 3.5 and 4.0 pH. While its prime growing temperature is between 40° and 45°C, it is very heat tolerant and can grow in temperatures ranging from 25° to 60°C. (Sourri et al., 2022)
A. acidoterrestris, is regarded as a primary threat to the fruit juice industry. These bacteria are identified in soil, on the surface of fruits, throughout points in the supply chain, and at several steps of fruit juice processing which results in Alicyclobacillus in fruit juice. Moreover, A. acidoterrestris is known to colonize materials used in food processing, including stainless steel, nylon, glass, PVC, and polystyrene, where it can form biofilms whose elimination is challenging. (Kunicka-Styczyńska et. al., 2020)
What Is the Impact of Alicyclobacillus on the Food Industry?
Alicyclobacillus is non-pathogenic and is therefore not a threat to human health. However, the difficulties associated with detecting Alicyclobacillus in food, the lack of visible deterioration customarily associated with spoilage, and the malodourous condition of contaminated fruit juices pose significant challenges for the fruit juice industry. Incidents of Alicyclobacillus spoilage in fruit juices have been found in fruit juices including orange, apple, mango, pear, grapefruit, banana, blueberry, passion fruit, watermelon, cherry, pineapple, pomegranate, and lemon juice. (Sourri et al., 2022).
Fruit juices undergo preservation methods to prevent spoilage while aiming to retain taste, quality, and nutritional value. They are made available freshly squeezed, chilled, frozen, pasteurized, and concentrated.
Control of Alicyclobacillus is a challenge for the food industry, most notably in fruit juice, because contamination of Alicyclobacillus in fruit juice has multiple entry points. It is the combination of Alicyclobacillus presence in soil, on fruit surfaces, contamination during harvesting, and the favorable environment during processing and packaging for Alicyclobacillus germination, growth, and spoilage. (Ciuffreda et al., 2015)
Alicyclobacillus spoilage in fruit juice is not visible during storage because there is no gas production. Alicyclobacillus in fruit juice causes a flat-sour type of spoilage, so there is no swelling of the juice containers. Control of Alicyclobacillus is similarly difficult as the bacteria survive conventional fruit juice processing protocols, including pasteurization, aimed at safe, high-quality fruit juices. Control methods such as physical, chemical, and biological treatments have been developed. Current research indicates that certain chemical or natural compounds may potentially prevent Alicyclobacillus spoilage. Cinnamic acid and dehydroacetic acid as fruit juice additives are examples of this type of control. (Cai et al., 2015)
Ensuring quality raw material and vigilant hygiene throughout the supply chain and processing will help control contamination of Alicyclobacillus in fruit juice. (Sourri et al., 2022)
Detection for Alicyclobacillus Spoilage Prevention
Detection of Alicyclobacillus is challenging due to the lack of visible evidence in fruit juice products. Therefore rapid testing for Alicyclobacillus in food, throughout the supply chain, processing, and packaging can safeguard the fruit juice industry from losses due to Alicyclobacillus spoilage.
Eurofins' network of ISO 17025 accredited laboratories offers an extensive selection of industry-standard methods for indicator and spoilage organisms, including Alicyclobacillus. We can offer traditional and rapid methods to evaluate Alicyclobacillus presence or absence on environmental surfaces, raw materials, and finished products, providing timely assurance that your product will stay fresh before and after production.
