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  1. The National Antimicrobial Resistance Monitoring System

Retail Meat Sampling

by Dr. Terry Proescholdt

DR. PROESCHOLDT: Thank you. Actually, I am going to start with the Iowa Study, because that is where we did start, and then work up to today.


Our pilot in Iowa was a statewide collection. We collected the same meats as the retail arm is right now. One difference was we collected fresh or frozen product. Fresh if available. Frozen if not. The retail arm now, I think, collecting only fresh is an improvement.

In our pre-pilot we tried collecting all ground meats, and this kind of speaks to your question, Dr. Vogel. We found that all ground meats, even though they would be easier to work with in the lab, didn’t work to collect. There was no ground chicken at all. And in the smaller grocery stores, about half of them did not have ground pork. They had ground sausage, but the extra spices and whatever would just complicate the bacterial picture.

I almost expected somebody would ask about the turkey, and I tried to look it up. The closest I could find was the National Turkey Federation web pages. They said the number one product was whole turkey, which is impractical, both budgetarily and it is very difficult to put a whole turkey in a Whirl Pak bag and shake it up.

The other thing they said, but there were no numbers involved, is that the ground product is the most rapidly growing in popularity. But I cannot find whether it is number two or number 10 as far as total volume. I couldn’t find it from Ag Marketing or the Economic Research arms of USDA either. I could tell you what per capita is and this sort of thing. So, I don’t know.

Anyway, this was laid out to be a 50-week sampling, but it was not 50 consecutive weeks because we had major holidays, like Thanksgiving, Christmas and 9/11 and that sort of thing that got in the way.


Bacteria of interest. The first three are being done now. The fourth one we looked, instead of generic E. coli, for extended spectrum beta-lactam resistant Enterobacteriaceae.


We bought a list of all the chain and single store groceries in the state. From that we took a random sample of 300 grocery stores. Let me backup a half step. From that list I went through it manually to remove any obviously inappropriate stores, because the listing then was a little less exact than it is now.

I will come back to that, but there were some convenience stores, nutrition stores and that sort of thing that crept onto the list. Those were easy to remove.

We took a random sample of 300 stores. From those 300 stores we divided the state into five quadrants of 60 stores each just grouping it by latitude and longitude. Then we grouped again by latitude and longitude six stores into a route. The quadrants were sampled sequentially to help with the seasonality. The routes within the quadrants were done randomly.

We also had a list of randomly chosen backup stores, which became very useful because convenience stores still were on our list here.

The meat was shipped on ice overnight to CVM for work up. Until 9/11 it was shipped as checked luggage in a cooler on an airplane.


That is how the store layout looked like. You can see where the major population centers are. That is Des Moines, Waterloo, Cedar Rapids, Iowa City.


For the retail meat of NARMS for the first three years it was convenience sampling. The FoodNet labs were asked to sample at least one store per month, to purchase as many different brands of meat as possible and not to revisit the same store for at least two months. Again, they bought 10 samples of each meat type each month.


What we are doing this year instead is a stratified random sampling. The FoodNet labs were contacted. They were asked, how big an area are you willing to collect from? From that area, again, we bought store listings for everything within the zip codes or counties that they specified.

We ended up with between 30 to 300 stores per state, depending on the areas given us. The listings now are much more sophisticated, at least visually, in eliminating the convenience stores. I did again visually inspect and remove inappropriate stores. There were a couple of wine stores. One smoke shop. The Aldi chain had to go because it has nothing but frozen meat.

The stores then were sorted into four quadrants by latitude and longitude, except for California. They are sampling three full counties. So we used them as quadrants.


Then I randomized the order that the quadrants would be sampled and that sequence is repeated sequentially. Again, for the seasonality. The stores within the quadrants were randomized, and for each month the FoodNet people got a list of five primary stores and three backup stores.

Any stores that weren’t put on those two lists were put on an ultimate remainder list just for a second set of backups.


If there were more than 60 stores in a state, the primary store was only sampled once a year. If there were less than 60, obviously it had to be seen again. But I made sure it wasn’t sampled twice in the same month. When there are greater than 96 stores, the backup stores were only sampled once a year.


In the store the FoodNet people were asked to collect two samples of each meat type in every primary store if they could, and also, if they could, try for two different brands or lots of each meat types. And then those samples that they could not collect in the five primary stores they were asked to collect in the backup stores.


This isn’t perfect yet. We found out that all of our listings missed the big discount stores, like Super Target, Wal-Mart, Sam’s Club and Costco. Tennessee pointed out to us that there were a number of small mom and pop grocery stores that are also missed.

I think this came in because the chain store guide only picks up single stores that sell a $1 million or more a year and chain stores $2 million. It is probably one of their ways of eliminating convenience stores.

From a quick talk with them I think we can add the discount stores in for next year. I don’t know if we can add the small ones in, but I will follow up on that. I want to try to encourage the states with the smaller number of stores to increase their collection areas so we can have some more stores to work with.

They have been quite good working with the system. Initially there was more than hesitation. Tom did a wonderful job with selling them into agreeing to this and looking at the log sheets that have come in they appear to have done a good job of staying with the list.

And again, I will keep getting rid of the inappropriate stores so they don’t have to be bothered by going to something they can’t get their samples from. But that is it in a nutshell. I hope I helped you catch up a bit.


DR. YOUNGMAN: Are there any questions for

Dr. Proescholdt?

(No response.)

DR. YOUNGMAN: Okay. Thank you, Terry.

Our next speaker is Dr. Elvira Hall-Robinson, and she is going to be talking about how the data is reported and collected.

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