Controlling Biofilms

Posted on 15 May 2017 by Valerie

Tags:

what_is_a_biofilm_fig_4.PNG

15/05/2017

 

 

“One of the real problems with biofilms is that they develop and grow in out-of-the-way places, behind gaskets and in screw threads.”

A quote from the article below is exactly what can happen with Biofilms causing many problems, especially in nurseries.

Biofilms also effect your watering by blocking drippers and sprinklers having devastating consequences on your crops and plants.

That is where Grayson Australia can help!

Vibrex is the perfect product that can help eliminate these problems.

 

Getting under the skin of pathogens

By Steve Bjerklie

 

Unfortunately, a biofilm is not a movie about the life of a celebrity. It is the stubborn skin-like substance exuded by pathogenic cells for self-protection., and can be devilishly difficult to remove. But controlling biofilms is the best way to prevent colonies of pathogens from barricading themselves and thus surviving.

 

A biofilm is essentially a polysaccharide. “Chemically, it’s very resistant, almost an adhesive,” says Terry McAninch, who heads the R&D department at Birko Corp., Henderson, Colo. “They’re hard to penetrate. There’s not a quick way to do it.”

 

“One of the real problems with biofilms is that they develop and grow in out-of-the way places, behind gaskets and in screw threads,” points out Dr Dale Fredell, manager of educational services for the food and beverage division of Ecolab, St. Paul, Minn.

 

In a recent study of 41 meat plants, Listeria monocytogenes, one of the meat industry’s most tenacious pathogenic enemies, was found living on 39 percent of the floors, 39 percent of the floor drains, 34 percent of the cleaning equipment (such as brooms, mops, and brushes), 24 percent of the wash areas, and 20 percent of the food-contact surfaces. Every one of these sites is prime territory for biofilm growth.

 

Biofilms are common in homes as well as in meat plants. That slime down around the drain in your shower? That’s a biofilm. The dark gunk at the corner of the moulding on your sink or around the base of your kitchen faucet? Biofilm is in there. “What it is, it’s slime, basically,” notes Fredell. Given the right bacteria, biofilms can grow in refrigerators, under toaster ovens, in the crevices of windowsills, and along the runners of sliding glass doors. They grow quite well on glass, in fact — and on stainless steel.

 

“One of the real problems with biofilms is that they develop and grow in out-of-the-way places, behind gaskets and in screw threads.”

 

Biofilms are, in their own way, an acid test for the true efficacy of a plant’s sanitation and disinfection program — for the true cleanliness, that is, of the operation. Unlike controlling the movements and vectors of Listeria monocytogenes, which involves, more or less, heading the bad guys off at the pass, controlling biofilms is about hunting down the sites where the films have established themselves and making the spot as clean as a food-contact surface can be.

 

The consequences of not doing the job right are serious, say both McAninch and Fredell. Behind the protective wall created by a biolfilm, pathogens multiply quickly, and can spread. Biofilm sites become like base camps from which Listeria and other highly mobile

Pathogens will venture out into the plant — or on to products. Trying to control these pathogens without killing biofilm sites is like treating symptoms but never curing the disease. And a meat plant dotted by biofilms is indeed microbiologically “sick.”

 

Biofilms are common in homes as well as in meat plants. That slime down around the drain in your shower? That’s a biofilm.

With the right chemicals — “oxidizing chemicals, such as chlorine bleach and hydrogen peroxide,” advises McAninch — getting rid of biofilms is difficult but not impossible, once they’re located. “It’s important to take apart equipment completely and really clean it,” says Fredell. “It’s the only way to get under the gaskets and down to the threads of bolts and screws, which are favourite biofilm hiding places. I advise a frequent thorough cleaning using a high-pressure spray nozzle and an effective disinfectant or sanitising cleaner.”

 

“Remember, biofilms are exuded by bacteria for defense. They’re designed to protect the bacteria from outside attack, including streams of water and chemicals,” says McAninch. “You’ve got to really scrub. Just because it seems you’ve washed away the film doesn’t mean that you’ve made that surface food-safe. It’s important to test the surface to make sure.”

 

Pre-rinse water should be at least 120° (140°F is better), hot enough to melt fat but not so hot as to parboil any biological material, and the pressure at a 3/16-inch nozzle should be at least 200 psi, but avoid aerosols that will spread pathogens and biofilms rather than eliminate them.

 

Pre-rinse water should be at least 120°F (140°F is better), hot enough to melt fat but no so hot as to parboil any biological material.

 

During the soaping and scouring stage, do not let soap or detergent dry, as this will create another protection for biofilms. Equipment must be hand-scrubbed, not just hosed down, to ensure thorough cleaning.

 

“Bio-luminescence doesn’t kill pathogens, it shows that kind of bacteria of all kinds you’ve got on a surface. That’s why it’s such a good tool for training.”

 

Remove cleaning chemicals with a flood rinse. Rinse walls, floors, and equipment in the reverse order the detergent was applied: Walls, then floors, then the equipment. Don not spray floor again after equipment has been rinsed.

 

When disassembling equipment, make sure there’s no standing water on any surface, as this will prevent sanitising cleaners from reaching the surface. After cleaning and reassembly, operate the equipment prior to inspection, and complete the formal pre-op procedure described in the plant’s Standard Sanitation Operating Procedures.

 

Swab-testing will show if any pathogens remain after a sanitising cleaning. Both McAninch and Fredell like bio-luminescence for a couple of reasons: one, the technology will show whether a machine is truly clean, and two, it’s great tool for training the sanitation crew.

 

You can have your sanitation trainees go to work on a piece of equipment and then use bio-luminescence to show them the spots they missed.

 

“Bio-luminescence doesn’t kill pathogens, it shows what kind of bacteria of all kinds you’ve got on a surface,” notes Fredell. “That’s why it’s such a good tool for training. You can have your sanitation trainees go to work on a piece of equipment and then use bio-luminescence to show them the spots they missed. It’s really effective for that. It’s amazing how often someone thinks they’ve cleaned something very thoroughly, and then a bio-luminescence tests shows all kinds of microbiological dirt still on the machine. As you know, with bacteria it’s not what you see, because you can’t see it. It’s how thoroughly you clean.”

 

Behind the protective wall, created by a biofilm, pathogens multiply quickly, and can spread. Biofilm sites become like base camps from which Listeria and other highly mobile pathogens will venture out in the plant — or on to products.

 

Floors — especially cracked or otherwise damaged tiles, grout, concrete, and mortar — and drains also need to be high-pressure sanitized and then tested for any residual biofilm growth. Walls, too. Employee welfare areas, especially restrooms, must be sanitised and disinfected as thoroughly as processing areas to rid a facility of biofilms.

 

Older equipment, with exposed bolts and threads, unsealed riverts, hollow conveyor belting, and other exceptionally good growth sites for biofilms, can be a special problem. Again, Fredell says the best way to deal with it is to subject the equipment to frequent every-square-inch super-cleanings.

 

“Remember, biofilms are exuded by bacteria for defense. They’re designed to protect the bacteria from outside attack, including streams of water and chemicals. You’ve got to really scrub.”

 

In an effort to improve the situation with regard to equipment, the American Meat Institute established the Sanitary Equipment Design Task Force in late 2001 to develop guidelines for the design and manufacture of meat-processing equipment that will resist contamination by pathogens and biofilms. The task force, chartered in direct response to some serious product recalls resulting from Listeria contamination of ready-to-eat foods, evaluated existing sanitary design standards, developed new principles of sanitary design, and also developed a model of application of the new principles. The task force also wrote and recommended a certification scheme for new equipment meeting the group’s SED criteria. The task force initially focused on processing equipment common in plants manufacturing ready-to-eat products, including slicers, dicers, sausage-casing peelers, conveyors, loaders, brine-chill systems, and horizontal form-fill-seal machine, but in time the SED program will expand to include all food-contact processing equipment found in a meat or poultry plant.

 

With the co-operation of several major processors, including Kraft-Oscar Mayer, Bar-S Foods, Hormel Foods, Sara Lee Corp., Tyson Foods, Excel, Minot, ConAgra, and Hatfield Quality Meats, the task force came up with several SED guidelines that, collectively, could revolutionise meat-processing equipment design from a food-safety standpoint.

 

 

For example, SED guidelines include no metal-to-metal contact (to prevent filings and to prevent potential sites for biofilm growth), no lap joints, completely smooth and polished wells (to avoid pits and uneven seams that can harbour (biofilms), sealed rollers and tubes on all conveyors, no fastener penetration of sealed tubes and rollers, no exposed screw and bolt threads, and no unsealed holes or crevices. The task force developed 10 SED criteria in all.

 

“Overall, I think the industry is doing a much better job controlling pathogens and biofilms,” says Ecolab’s Dale Fredell. “There’s been tremendous improvement, and much better monitoring. The problem won’t ever be licked completely — controlling pathogens and biofilms is about constant vigilance. But from what I see in the industry today, processors really understand that.”