Food Safety Happens in a Vacuum

While dissecting and evaluating the product safety and process control measures in question, he realized that one of the weakest links in the chain was surface sampling and the pathogen-extraction process from the food product itself, along with surfaces the food may touch during the manufacturing process. Dr. Bradley then narrowed his focus to the area of surface sampling—and the Microbial-Vac System was born.

The Microbial-Vac System, or M-Vac, is a wet vacuum surface sampling system that shares several characteristics with a carpet cleaner. Imagine the hand-held attachment used to clean a piece of furniture: Omit the rotating brushes and add in the fact that the M-Vac is sterile and smaller, and the idea is the same.

The sampling hose enables the user to reach difficult areas with the sampling head.

Just as a carpet cleaner sprays down a solution to get the deep dirt out of the fibers, cracks, and crevices of a carpet or couch, the M-Vac System sprays down a solution and at the same time vacuums the pathogens out of a food surface. Especially compared with the sponge and swab sampling methods, the M-Vac System is significantly more effective.

The M-Vac has shown consistently greater recoveries than most other sampling methods and, due to its scalability in covering larger surface areas, is essentially unlimited in its sensitivity (see Table 1). These capabilities and more are exactly what one would expect when closely evaluating the wet vacuum concept.

The secret to the M-Vac System’s effectiveness is that the pressurized, sterile liquid is applied at the same time as the vacuum. That combination creates what Dr. Bradley called the LAMDAC principle: liquid-assisted microbial detachment and capture. It’s what enables the M-Vac to effectively extract pathogens, viruses, drug residue, and virtually any other type of microscopic particle from a surface, including those that are embedded and/or attached.

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Table 1. Recovery of Common Food Pathogen Simulants from Representative Food Processing Environmental Surfaces

The M-Vac is a much more aggressive form of sampling, bringing to bear multiple elements to extract every possible particle from a surface. This is critical when dealing with bacteria such as E. coli, Listeria, Salmonella, or the many other foodborne illness-causing adulterants. Even one cell that is missed can quickly multiply into billions and wreak terrible havoc on the populace. The most dangerous scenario is when the QA sampling is done at the right place and at the right time, and the sampling method fails to extract the contamination, giving the producer a false negative reading and a false sense of security.

Meaty Motive

The M-Vac System was originally designed for the meat industry, to sample carcasses shortly after slaughter. Dr. Bradley knew that the vast majority of pathogens enter a meat-processing facility on the hide, getting onto the meat during the removal of the hide, and that it would be best to detect those pathogens as early as possible after the hide is removed.

Dr. Bradley believed sampling product post-production is almost worthless, because by that point it is too late in the process to really do anything about the contamination other than destroy or cook the contaminated product, which is, at best, a small percentage of the overall product volume. Most importantly, it tells the plant little about the upstream process and nothing about where the contamination came from. The higher up the chain the sampling is focused, the more it can be used as a process control tool, giving the plant actionable information.