The food safety watchdog delivered its verdict following a request from the European Commission to assess “the safety and efficacy of lactic acid when used to reduce microbial surface contamination on beef hides, carcasses, cuts and trimmings”.
Brussels specifically asked EFSA’s experts to consider the toxicological safety of the substance but also whether widespread adoption had the potential to lead to an upswing in bacterial resistance to biocides and therapeutic antimicrobials.
The Parma body was also tasked to evaluate risk related to the release of lactic-acid containing effluents from slaughterhouses and processing plants.
No toxicological concerns
After assessing 25 studies that met its criteria, EFSA confirmed that it broadly believed lactic acid was effective in killing bacteria in beef compared to use of water rinses, while dismissing concerns over increased antimicrobial resistance and a potential environmental threat from processing wastewater containing the substance.
There were no concerns expressed about possible human toxicological effects because of “the expected low level of exposure deriving from the use of lactic acid on carcasses, cuts and trimmings, and the fact that it is an endogenous substance”, said experts from the CEF and BIOHAZ panels.
They stressed however, that treatments should have a lactic acid content of between two and five percent at temperatures of up to 55°C applied either by spraying or misting.
No assessment on the efficacy of processes involving lactic acid followed by water rinsing was made as no studies were submitted, said EFSA.
The panels did not attempt to assess the efficacy of every process presented in the more than two dozen studies it examined – but acknowledged that factors such as lactic acid concentration, method of application, time and temperatures were all factors that would impact on performance.
However, EFSA said: “It was concluded that, although variable, microbial reductions achieved by lactic acid treatment of beef are generally significant compared to untreated or water treated controls.”
High, medium and low
Based on the nature of the processes, EFSA classified them into providing high, medium or low strength of evidence for microbial reduction. For example, studies on industrial scale and pilot scale which were representative of industrial scale with naturally contaminated products were considered as providing high strength of evidence.
Based on high strength evidence' studies the experts said that while lactic acid reduced counts of naturally occurring Enterobacteriaceae on beef to “a variable' degree”, these reductions “were usually significantly higher compared to untreated or water treated controls”.
Studies demonstrating high or medium strength evidence showed the substance cut the prevalence of Salmonella and/or Shigatoxin-producing/Verotoxin-producing Escherichia coli (STEC/VTEC) on carcasses, beef cuts and trimmings to varying degrees depending on study design and contamination level.
Based on studies classified as 'medium strength evidence', it “was shown to reduce counts of inoculated pathogens (Salmonella and/or STEC/VTEC) on beef carcasses, cuts and trimmings to a variable degree”. These reductions were usually higher on carcasses compared to meat cuts and trimmings, said the panel.
EFSA also concluded that the development of enzymatic resistance to therapeutic antimicrobials as a result of exposure to lactic acid was unlikely – even though no data was provided.
The possibility of mutational change resulting in the development of resistance to therapeutic antimicrobials is also unlikely to be a significant issue because lactic acid is so naturally prevalent.
Risks from lactic-acid containing waste presenting an environmental threat were “considered negligible” and the panel said a risk assessment was unnecessary.