New Antimicrobial Treatments Are Enhancing Food Safety in the Plant

Chemical treatments that sound innocuous or don’t have to be listed on labels are becoming common, but precision application is a must for effectiveness and cost control.

By Kevin T. Higgins, Managing Editor

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Last month, Riemer was issued a U.S. patent for an ultrasonic atomizing nozzle that gives processors greater control in high-speed dosing of antimicrobials than nozzles powered by hydraulic pressure. Piezoelectric transducers create mechanical motion in the nozzle’s atomizing section, producing droplets in the 5-50 micron diameter range, compared to up to 500 microns with hydraulic nozzles. The larger droplets “create a small swimming pool” on the surface of food, he contends.

Customer expectations

USDA has strict requirements for combating listeria monocytogenes in ready-to-eat meat and poultry, but some customers are beginning to go beyond those standards. According to Riemer, Sysco began requiring a validated post-lethality treatment with a listeria reduction treatment late last year, as well as an inhibiting antimicrobial in the formulation.

Many processors are opting for HPP treatment to satisfy the requirement, but Reimer maintains surface treatment at packaging is a simpler, less costly alternative -- provided consistent dosing can be validated.

No antimicrobial can deliver both bacteristatic and bactericidal protection, allows Roger Maehler, senior director-seasoning R&D at Newly Weds Foods. But if an additive can both inhibit growth and lower the temperature at which surviving pathogens are killed, food safety is enhanced. That was the goal of researchers in Chicago-based Newly Weds’ IsoState products group when developing DefenStat, a clean-label additive introduced at IPPE.

Designed for raw meat and poultry, the ingredient was developed over three years to address the problem of inadequate refrigeration temperatures during distribution and storage. Refrigeration is the primary defense against bacterial growth, yet 40 percent of raw products experience higher than acceptable temperatures, according to Maehler.

DefenStat inhibits microbial growth in that event and as a result of cross contamination. It also makes remaining pathogens susceptible to thermal destruction at temperatures about 12°F lower than the recommended critical control point. For example, steak should be cooked to 145° and poultry 165°. With DefenStat, a 133° steak or 153° chicken most likely wouldn’t pose a health risk.

Maehler characterizes the ingredient as imparting a “savory flavor to products. “We are flavor people,” he points out. “If anything, it’s preferred over meat or poultry with no added ingredient.”

Listing such an ingredient as vinegar or lactate on a label might pass muster with consumers, but listing nano silver would give many people pause. Residual levels of silver dihydrogen citrate (SDC) of up to 30ppm on poultry and produce, on the other hand, are deemed acceptable processing aids by FDA, exempting SDC from label disclosure, according to Hank Lambert, CEO of Pure Bioscience Inc. And he has a letter of no objection (LNO) from FDA to prove it.

El Cajon, Calif.-based Pure attained EPA registration for its food-contact surface sanitizer and environmental disinfectant several years ago, but last year it petitioned FDA for use of SDC in direct contact with food. Approvals recently were received for both poultry and produce, and FDA issued a LNO for raw fruits and vegetables in February. Lambert expects a similar letter for poultry in the spring.

Toxicity of SDC is extremely low, he says, and it kills bacteria faster than peracetic acid and acidified sodium chlorite, with “no organoleptic impact, no off odors, no discoloration, no negative impact on nutritional value.” Moreover, it doesn’t reduce yield: “Peracetic acid cauterizes fat,” Lambert says. “If a 10-lb. bird goes into an immersion chiller, it might come out as a 9.8-lb. bird. With SDC, it remains 10 lbs.”

Unlike most chemicals, SDC’s effectiveness in killing bacteria, mold and viruses is not impacted by temperature. However, rigor in mixing and blending silver ions in citrus acid and water to achieve the correct suspension must be followed. Pure worked with Spraying Systems and an engineering firm to develop a skid-mounted system to ensure correct procedures are followed before the fluid reaches the nozzle and beyond.

Human beings are a sometimes overlooked source of cross-contamination, along with the air itself in a plant. Vendors are beginning to upgrade hand-washing stations. The humble towel dispenser is the initial focus of SCA Americas, the Philadelphia-based subsidiary of the Swedish firm Svenska Cellulosa Aktiebolaget. SCA is segueing from foodservice to industrial food production, beginning with a high-capacity towel dispenser that’s been certified by HACCP International. Fewer roll changes is a convenience, but hygienic design is the more important benefit, thanks to the elimination of harborage points and contours that tolerate high-pressure washdown.

“We are going to continue to innovate, and there are a number of wash-station improvements we’re going to introduce,” says Tom Bergen, market director-health care & industrial. “With the towel dispenser, we’re making sure we have the right system before entering the market in a big way.”

Hand washing seems prosaic, but the devil is in the details when combating invisible threats to food safety. In today’s environment, a button-down approach is the order of the day.

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