A study warns of the risks of cross-contamination during the production of unpasteurized juices

• Gloves and cutting boards are the surfaces with the highest risk of bacterial transfer 

• The work evaluates the transfer of pathogens in the production of fresh strawberry, apple and beetroot juices 

A team of researchers from Agrotecnio and the University of Lleida has published a pioneering study that analyzes how certain pathogens can contaminate unpasteurized juices made with fruits and vegetables, through contaminated handling surfaces.  The research has shown that three bacteria of high health risk —Salmonella enterica, Escherichia coli O157:H7 and Listeria monocytogenes— can be transferred from gloves, knives and cutting boards to fruits and vegetables and, subsequently, to the final juice obtained.  The study focused on the production stages of fresh strawberry, apple and beetroot juices, reproducing common situations in domestic environments or small workshops, such as the consecutive preparation of several batches with the same equipment without properly cleaning it.  The results show a real risk of cross-contamination: after a first batch of juice made with contaminated products, the bacteria can persist in the subsequent batches of juice, even when using non-contaminated fruit.  Regarding the use of surfaces, contaminated cutting boards and gloves are those that promote a higher bacterial transfer, while knives represent a lower risk.  As for the raw material, the survival of pathogens in the juice varies according to the fruit or vegetable. Strawberry juice reduces bacterial presence more quickly, while beetroot juice allows for a longer survival, probably due to the effect of its higher pH and some natural compounds present in this vegetable. Apple juice shows an intermediate behavior.  “This work gives us very valuable information for the industry, but also for local producers and consumers who make fresh juices. We demonstrate that, in the absence of thermal treatments such as pasteurization, very strict hygiene protocols are needed to minimize risks, especially in processes where fruits and vegetables are mixed,” explains Isma Neggazi, researcher at Agrotecnio and the University of Lleida.  The researchers recommend exploring alternative technologies to ensure the safety of these products, such as the application of high pressure or the use of natural antimicrobial compounds. In addition, they insist that controlling contamination in the early stages of processing is key to protecting consumer health.  The study is part of the QUALISAFEJUICE project, funded by the Ministry of Science and Innovation, which seeks to improve the quality and microbiological safety of fresh juices. This work by the Postharvest Biology and Technology group of Agrotecnio – University of Lleida is one of the first to systematically analyze the transfer of pathogens during juice production under real handling conditions. The research has been led by Isma Neggazi, Pilar Colás-Modá, Immaculada Viñas and Isabel Alegre.  More information:  Cross-Contamination of Foodborne Pathogens During Juice Processing (https://www.mdpi.com/2079-7737/14/8/932)