Multiple Hurdles Minimize Pathogens
Progress reports released by USDA's Food Safety & Inspection Service (FSIS) in March and October 1999, show that meat and poultry plants are substantially reducing the incidence of Salmonella on raw products.
Beyond promulgating Sanitation Standard Operating Procedures (SSOPs) and the Hazard Analysis & Critical Control Points (HACCP) system, the agency's final rule on Pathogen Reduction and HACCP (the MegaReg) of July 25, 1996, requires that slaughter plants test for generic E. coli to verify that they are preventing fecal contamination. FSIS inspectors monitor the results.
Meanwhile, to verify that HACCP systems are effectively controlling contamination of raw products, FSIS analyzes samples from slaughter plants and ground-meat plants for Salmonella, and measures results against performance standards developed from nationwide microbial baseline surveys conducted before the MegaReg took effect. FSIS plans to adjust these standards as new data become available.
In the pre-HACCP baseline studies, Salmonella was found on 20 percent of all young chicken carcasses, 8.7 percent of all hog carcasses, 7.5 percent of all ground-beef samples and 49.9 percent of all ground-turkey samples.
The MegaReg's HACCP and microbial-testing requirements took effect at large meat and poultry plants (500 or more employees) on January 26, 1998. These plants account for about 75 percent of all slaughter production. After the first year of compliance, as shown on the table on page 76, large plants substantially reduced the incidence of Salmonella on their products. Results for the first six months of 1999 show continuing reductions in large plants.
Small plants (10 to 500 employees) were required to comply with HACCP and microbial testing starting January 26, 1999. Results for the first six months, shown on the table on page 77, indicate that these plants too are off to a good start in reducing Salmonella.
Very small plants, those with fewer than 10 employees or annual sales of less than $2.5 million, must start complying next month -- January 25, 2000.
Beef interventions
Multiple interventions or "hurdles" to reduce pathogens on meat carcasses include sanitary plant design and good manufacturing practices (GMPs) as well as HACCP, said Dr. Jerry Leising, vice president and R&D director of Cargill's Red Meat Group (which includes Excel beef and pork products) at a food safety conference sponsored by Ecolab September 9-10 in St. Paul, MN. Future interventions will include chemical treatment of carcasses and -- imminently as this story went to press -- irradiation of ground beef, he added.Excel, the nation's second largest beef packer, operates seven beef-slaughter plants, two hog-slaughter plants and four further-processed red-meat plants in the U.S. Cargill further operates four turkey plants in the U.S., as well as meat and poultry plants in Canada, the U.K., Australia, Honduras, France and Thailand.
Sanitary plant design includes air filtration in high-risk areas and overpressure flowing outward from "clean" areas toward "dirty" areas, said Leising. Water must meet EPA potability standards and is chlorinated at 0.2 ppm. Process flow minimizes the possibility of cross-contamination by segregating slaughter operations from fabrication, including the people involved in these two areas. A properly designed plant will also reduce the time, labor and chemical costs of sanitation, Leising pointed out.
In addition to air and water controls such as scheduled filter replacements, monitoring airborne particulates and chlorination of water, GMPs include proactive pest control, scheduled cleaning operations in addition to the daily sanitation shift, and personal hygiene rules. Process GMPs include slowing linespeeds "on-the-fly" to allow time for cleaning dirtier animals; disinfecting knives between skinning cuts; frequent rinsing of gloves, aprons and other equipment; isolating organs which could cause cross-contamination; and job procedures designed to prevent cross-contamination.
Cargill has implemented HACCP at its meat, poultry and egg plants since 1991, Leising continued. HACCP at Excel beef-slaughtering plants incorporates three Critical Control Points (CCPs):
- Final carcass inspection (after washing) for zero fecal material;
- Steam pasteurization of split carcasses (sides) to a minimum surface temperature of 180° F;
- Carcass chilling to a maximum surface temperature of 40° F and maximum deep-muscle temperature of 48° F.
Microbiological testing validates HACCP through trend analysis of indicator organisms including total plate counts, coliforms and generic E. coli, Liesing continued. Excel focuses on carcass and ground beef counts. For example: Before HACCP implementation in 1990, aerobic plate counts on ground beef averaged 48,000 cfu/gm. Since HACCP implementation, average aerobic plate counts have steadily declined from 15,000 in 1991 to 5,000 in 1999. Microbiological testing is also used to determine product shelf life, for environmental analyses (air and water), and to monitor equipment sanitation. Pre-operational sanitation of Excel plants is validated with a computerized sanitation program.
Future chemical interventions include sanitizing solutions such as peroxyacetic acid (Ecolab's tsunami) and octanoic acid, both effective over a broad pH range and less affected by organic matter than other sanitizers. Unlike chlorine, which leaves residual by-products in the water, peroxyacetic acid (POAA) decomposes to water, oxygen and acetic acid. Octanoic acid is synergistic with POAA in microbial reduction by reducing the surface tension on carcass application. A solution of POAA and octanoic acid at 63 ppm, for example, reduces Listeria monocytogenes on meat surfaces by more than 5 logs in 30 seconds, while POAA alone at 116 ppm requires two minutes to achieves the same reduction. POAA alone at 116 ppm, however, matches POAA with octanoic acid at 63 ppm to reduce E. coli by more than 5 logs in 30 seconds.
Cargill has partnered with TitanScan to irradiate packaged ground beef at Titan's Sioux City, IA electron-beam facility as soon as FSIS issues its final rule on irradiation, Leising concluded. Excel expects to start test-marketing these products in January.
According to Mike Gangel, president of Chad Co. (Olathe, KS), "there is a misconception by some in the meat industry that everyone uses steam pasteurization. This is not correct." Chad's hot-water carcass-pasteurization system is currently installed in 16 meat-packing plants and -- at this writing -- was about to be installed in two more. The Chad system incorporates two antimicrobial treatments: pasteurization with hot water at 185° F for a minimum of 5 seconds, followed by organic acid pasteurization. According to Texas A&M University research, carcass surfaces treated with hot water at 203° F for 5 seconds and a 2 percent lactic-acid solution at 131° F reduced positive samples of S. typhimurium, generic E. coli and E. coli O157:H7 to zero (outside inoculated areas) following either wash-water/sanitizer or trim/sanitizer treatments.
Poultry interventions
Dr. Michael Benson, R&D director at turkey processor Jennie-O Foods (a unit of Hormel), reviewed multiple poultry-process interventions at the Ecolab conference.Jennie-O's Willmar and Melrose, MN plants volunteered for the FSIS HACCP-based inspection models project, designed to test new FSIS inspection procedures along with revised plant HACCP and process controls. As part of the models project, FSIS contracted with Research Triangle Institute (RTI) to collect baseline data. The Jennie-O plants are also testing various interventions as part of this study. As reported earlier by Food Engineering (October '99), FSIS approves experimental protocols on a case-by-case basis.
As of early September, RTI had collected turkey microbiological baseline data on six pathogens, Benson reported. This data will be used by FSIS to develop microbiological performance standards for plants. Although RTI data show that Salmonella was found industry-wide on 18.6 percent of whole turkey carcasses, Salmonella was found on only 9 percent of Jennie-O carcasses. Benson attributes this to farm interventions practiced by Jennie-O suppliers such as the Willmar Poultry Co., which has reduced the number of hatched birds carrying Salmonella from 90 percent in 1996 to 20 percent in 1999.
Process interventions at Jennie-O include pH adjustments to scald water; rectal plugs; scrubbers and washers such as inside/outside bird washers (IOBWs) and acid cabinets; vacuum steam pasteurization; the BOC Macron Loop; and alternative chemical treatments including chlorine, chlorine dioxide, POAA and ozone. These interventions have reduced total plate counts on carcasses from 550,000 pre-evisceration to 2,700 post chilling, and generic E. coli counts from 8,900 pre-evis to 150 post-chill.
The Macron Loop chill-water filtration and disinfection system (FE March '98; March '99) provides continuous process water at 800 gpm per chilller, filters-out organic particles larger than 25 microns (half the diameter of human hair), ozonates the filtered water to kill bacteria, and recyles the cleaned water back into the bath. The Loop improves the effectiveness of any antimicrobial treatment in the bath, said Benson, and is being used with chlorine, chlorine dioxide and POAA as well as ozone. Chlorine dioxide, like POAA, breaks down into oxygen and acetic acid. Tests to date show that chlorine dioxide reduces E. coli by 5 percent and total plate counts by 20-25 percent as compared to control in the chill water. POAA, however, seems more effective. As of early September, POAA had not yet been cleared by FSIS for use in poultry chill water, so Jennie-O was testing it off-line in a mini-chiller. At 25 ppm, POAA reduced E. coli by 85 percent, total plate count by 65 percent, and Campylobacter by 10 percent. At 100 ppm, PPOA reduced E. coli by 99 percent, TPC and Campylobacter to zero. Since FSIS' October 20 final rule on meat/poultry plant sanitation waives prior approval by USDA of chemicals approved by FDA and EPA, Jennie-O hopes for "little or no objection" from FDA to POAA, said Benson. "Our long-term objective is to have a chlorine-free process."
Another intervention which recycles process water is the Cascade system, developed specifically for poultry kill plants by Zentox Corp. in partnership with Praxair (FE October, '99). The system utilizes ozone to kill microorganisms in used water from other intervention points such as IOBWs and rinse cabinets, then returns the water to reuse points such as the evisceration line, chiller makeup and scalder. Available in several sizes ranging from 200 gpm to 1,000 gpm, the system first removes particulates through flotation and filtration, then injects ozone and returns water to the process. Zentox furnishes turnkey installation, engineering and on-site management; Praxair supplies the ozone generators and bulk oxygen.
According to Steve Moore, commercial development manager at Praxair, a Cascade system started-up September 17th at a major Georgia poultry plant.
Processors can realize savings in three ways, says Moore: the cost difference between reused water and single-use fresh water; reduced capital expenditure for wastewater treatment to meet increased flow rates; and increased production. He cited a water-restricted plant which can't get enough water for two shifts so it operates only 14 hours per day. "We're proposing a system that will get them back up to 16 hours yet save water," said Moore.
HACCP software
Food processors are applying software designed to help them monitor and control their HACCP programs. Example: Zartic, Inc., a four-plant processor of meat and poultry products based in Rome, GA, last October installed the HACCP and Quality data-monitoring and control systems developed by Bradley Ward Systems, Inc. (Atlanta). Bradley Ward supplies enterprise-wide and plant-floor automation software with its Key2Success integrated suite of modules designed specifically for food manufacturers.The Key2HACCP-Plan module helps the user perform hazard analyses; identify hazards and critical control points; create, archive and modify a printed HACCP plan. The Key2HACCP-Execute module collects and stores CCP monitoring and corrective-action data in a database for easy retrieval of HACCP records.
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