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USDA Appendices Updates, Straight from AAMP

  • Post By: Ray Humienny

When the USDA says that they’re moving toward a science-based approach for Appendices A&B revisions, you might think to yourself, “well, what the heck were we doing all this time?”

The American Association of Meat Processors (AAMP) highlighted these monumental changes at its 80th annual convention and suppliers’ exhibition in Mobile, AL. During the event’s opening ceremony, Food Safety and Inspection Service deputy administrator Paul Kiecker noted that USDA modernization efforts are beginning to tackle issues greater than line speed alone.

Simply put, USDA Appendix A&B revisions will provide guidance for small and “very small” processing facilities in the cooking and cooling of various beef and poultry products.

Specifically, the notable revisions are:

  • Appendix A:
    • “When heating meat or poultry products of any size when the cooking time is less than 1 hour to any internal temperature and time combinations in Appendix A, the Poultry Time-Temperature Tables, and the 5-log table, the Relative humidity of the oven is maintained at 90 percent for the entire cooking time.”
    • However, “relative humidity requirements (are) only applicable to semi-permeable or impermeable casings.”
  • Appendix B:
    • Revision of Option 2 Cooling Times: “120°F to 80°F in less than one hour, and 80°F to 40°F in less than 5.0 hours”
      • “Eliminated 120°F to 55°F in less than 6.0 hours option.” This was “thermodynamically impossible to achieve for many products thicker than 4.5 inches.”
    • “Partially cooked products must be cooled using Option 1: 130°F to 80°F in less than 1.5 hours, and 80°F to 40°F in less than 4.0 hours”
    • New concern regarding Bacillus cereus

Getting the industry involved

What makes these revisions specifically “science-based” comes from a long chain of USDA FSIS modernization efforts.

The history of USDA Appendices A&B began in the 1970s primarily as a how-to for cooking beef in smokehouses. After an era of command-and-control style regulations, the USDA’s FSIS amended these types of guidelines in 1996 and moved toward HACCP-based performance standards, so long as they had scientific backing on pathogen reduction.

However, they could not provide the “how” when it came to eliminating pathogens.

“We need to be able to demonstrate that the product is safe,” said Scott Updike, Ph.D., from the American Meat Science Association (AMSA). Updike emphasized the importance of empirical testing—rather than anecdotal evidence—on how to eliminate infectious bacteria while cooking meat.

The 1999 edition of Appendices A&B provided easy support for processors on how to combat pathogens, yet the lack of empirical evidence behind these cooking methods in the years to follow resulted in what Updike referred to as a scientific gap. This gap is defined as a process used in industry without the scientific data and literature to support it.

Although these processes are not inherently negative, the lack of valid and reliable research on such processes reveals limited conclusions on how they work. In the case of Appendices A&B for smaller processors, this means that the approach to cooking beef has fallen more and more under the scrutiny of FSIS researchers.

Understandably, plant owners have not been silent about it.

Unlike other guidance documents from the USDA, the 2018 revised Appendices A&B underwent a public comment period to compensate for the scientific gap in cooking procedures. To give an idea of what participation has yielded in the past, a recent FSIS modernization received approximately 83,000 comments regarding the inspection of swine slaughtering and butchering.

So far, researchers have been keen to respond to public comments. For instance, Jeff Sindelar, Ph.D., from the University of Wisconsin-Madison, summarized a working group’s efforts on what the revised Appendices mean for industry leaders at AAMP 2019.

The scientific approach

Sindelar explained that much of the Appendices’ scientific backing originates from a study conducted in 1978 titled “Fate of Salmonella Inoculated into Beef for Cooking” by the American Bacteriological and Chemical Research Corporation. This document was supported and contracted by the meat industry, and it is accepted by the government as a utilized, “USDA-approved” protocol.

Its researchers, S.J. Goodfellow and W.L. Brown, first injected 1-gram, cooked meat samples of different internal temperatures into test tubes submersed in water. This technique enabled them to calculate D-values for each sample, or the time it takes to destroy 90 percent of pathogens (i.e. a 1 log reduction).

Goodfellow and Brown then validated their findings by building thermal profiles via a dialysis tubing technique. This procedure offered a time-temperature table of processing times necessary to kill Salmonella with a D-value of 7 at various temperatures.

Finally, a surface lethality test was performed to examine how a mixed steam injected/dry roasting method would eliminate pathogens along the surface of beef within a single truck batch oven. Here, a breakthrough was uncovered: a lack of humidity resulted in no elimination of pathogen along the product surface.

Accompanied by his working group, Sindelar studied the effects of humidity in an impingement oven on a variety of meat products to eliminate pathogens. This research accordingly focused on the revisions made to Appendix A. Following his experimentation, two requirements were proposed to ensure surface lethality:

  1. The surface heat would reach an approved time-temperature combination, and
  2. The surface would be hydrated during this time:
  • Surface wetting conditions occur when the wet bulb temperature of the oven is greater than the surface temperature of the product. Drying conditions take place when the opposite is true.

Although humidity works to ensure surface lethality, there has yet to be an identifiable mechanism (e.g. cooking time, relative humidity, product weight, etc.) that is measurable to support “humidity parameters.” Additionally, Sindelar will continue to conduct similar tests with products including BBQ and jerky.

Regarding Appendix B, Sindelar and his working group observed various cooling times for an uncured turkey product (73% moisture) and discovered that a 1 log reduction in pathogens did not occur until a 1.5 to 2 hour phase cooldown from 120°F to 80°F. Similar to his results on Appendix A, Sindelar anticipates a continued effort on formulating an extended cooling standard.

Anticipate a verbal announcement from FSIS later in 2019. In the meanwhile, FSIS is more than willing to listen to your comments and concerns regarding any upcoming research on Appendices A&B. Let them know your process, no matter how small or customized. A science-based approach requires a collaborative effort to better the meat industry.