Posts Tagged ‘contamination control’

Restaurant News: Salmonella Is More Resistant to Disinfectants than Ever

February 27, 2014

Food safety is top priority to those in the restaurant industry; food-borne illness is no joking matter. Salmonella is one of the more common bacterium lurking in the corners that restaurant business operators must attempt to guard against. It is most commonly found in raw meat and can typically be killed by thoroughly cooking food through. Unfortunately, a recent study published in Applied and Environmental Microbiology has demonstrated that salmonella has now become resistant to disinfectants to the point where, if it is allowed to form a biofilm on surfaces, it can be difficult, if not impossible, to kill.

The Food-Borne Illness Outbreak that Prompted a New Look at Salmonella

The study into salmonella’s new resistance to disinfectants was conducted by researchers from the National University of Ireland, Galway, when 160 people in 10 European countries got sick from the Agona serotype of salmonella. After some investigation, it was discovered that the source of the outbreak was meat from a food processing facility with a wide distribution range. It was further discovered that the biofilm that salmonella can create on hard surfaces, such as those found in just such a food processing facility, is nearly indestructible once it gets established.

Only One Disinfectant Tested Could Kill Salmonella, and Only in its Early Stages

The biofilm of salmonella forms on hard surfaces and gets denser and more securely attached as time passes. The researchers tested three common disinfectants on a variety of hard surfaces: sodium hypochlorite, sodium hydroxide and benzalkonium chloride, in two stages of salmonella biofilm development; early (48 hours) and relatively mature (168 hours). While all three disinfectants did lower the counts of salmonella, sodium hydroxide was the only one to effectively eradicate the biofilm in its early development stage. Worse, not a single one of the agents could kill the mature biofilm, even after being soaked for 90 minutes!

Is This Resistance to Disinfectants Found in All Types of Salmonella?

The researchers of this study were curious to know if there was anything special about this particular strain of salmonella that allowed it to survive so successfully on the hard surfaces of the food processing facility. The answer is, unfortunately, no. In fact, the study found that every single type of salmonella they examined was able to adapt to the specialized biofilm lifestyle, on every single surface they tested. This includes glass, stainless steel, glazed tile and plastic.

Obviously, this is troubling news for food-service businesses. Letting a salmonella biofilm develop that can’t be killed is equivalent to going out of business. While there’s not much that can be done about salmonella’s growing resistance to disinfectants, restaurant operators should continue to take the precautionary measures against food-borne illnesses that they always have taken.  This includes being mindful of cross-contamination, especially on hard surfaces prone to the development of salmonella, and serving foods that are thoroughly cooked. This study only underscores the necessity for continued and improved vigilance on the part of restaurant operators as science works to neutralize these nasty bacteria.