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S T A T I S T I C A L Q U A L I T Y CONTROL A P P L I C A T f O N S FOR PROCESSED M E A T S

D O N A L D PAUL

O S C A R M A Y E R & Co. MAD I S O N , W I S C O N S I N ________ .___________- - - - - . . - - - . - - - - - - - - - - - - - - - - - - - - - - - - - - . - - - - - - - - - - - . - -

I would like to express my appreciation for the invitation to appear before this distinguished group and I hope that this material will be of interest to you despite the relatively elementary nature of the sub- ject matter.

I have been asked to discuss with you the present status of the application of statistical quality control techniques in the meat industry, with particular emphasis on the relationship of these applications to pro- duction, packaging, merchandising, and regulatory activities. This is a very broad subject and you will be relieved to know that the presentation is to be limited to 20 minutes. Therefore, it is my intentioc to present a brief discussion of the various statistical quality control applications in the meat industry of which I am aware, and if additional information re- garding any particular application is desired, I will be happy to discuss these with you in greater detail during the question and answer period.

In order to define the scope of the problem I thought you might be interested in some yearly industry production figures for the meat in- dustry. I should add that the figures that I will give represent only the federally inspected production. The percentages of the various types of meat product which are produced under federal inspection vary from an esti- mated 85% to 90% for fresh meat to 60% to 65% for sausage products.

During 1964, there were 25 million head of cattle and 72 million head of hogs slaughtered in federally inspected establishments. These animals produced 15 billion pounds of beef and le billion pounds of pork, 3 billion pounds of lard and rendered pork fat, $ billion pounds of tallow and 1 billion pounds of margarine and cooking compounds.

The processed meat industry used these raw materials to produce:

2,577,000,000 lbs . of Smoked Cured Pork 1,152,000,000 lbs. of Sliced Bacon 2,698,000,000 lbs. of Sausage 2,037,000,000 lbs. of Canned Meats

As a matter of additional interest the total sausage category breaks down to 295,000,000 lbs. of fresh sausage, 149,000,000 lbs. of dried and semi-dried sausage, 774,000,000 lbs. of wieners and frankfurters, 776,000,000 lbs. of other cooked sausage, 234,000,000 lbs. of loaves and 470,000,000 lbs. of sliced and packaged sausage and loaves.

As you can see from the foregoing data the meat industry produces a tremendous volume of inherently variable, extremely perishable and

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r e l a t i v e l y expensive products. t ions , types, c l a s s i f i ca t ions and q u a l i t i e s of meat products. It i s not unusual f o r a l a rge meat processor t o produce several hundred o r more d i f - ferent meat products.

In addition, there i s a vas t a r ray of var ia-

It i s obvious from the above t h a t anyone so foo l i sh as t o g e t i n to the meat processing i n the f irst place must have control of his operations i f he i s to have a successful business. It is equally apparent t h a t the combination of la rge volume and small package s i zes provides a ready appl i - cat ion f o r s t a t i s t i c a l sampling and control pr inc ip les . Fortunately, the s t a t i s t i c a l p r inc ip les and techniques used need not be complicated. Only an understanding of control char t theory and f a m i l i a r i t y w i t h the meaning of simple such terms as normal curve, variance, standard deviation, prob- a b i l i t y and the l i k e i s necessary. Actually, a thorough understanding of the cha rac t e r i s t i c s of the normal curve is a l l t h a t is required t o make many prof i tab le appl icat ions i n the meat industry.

The most common appl icat ion of s t a t i s t i c a l qua l i t y control tech- niques i n the meat processing industry is their use i n quant i ty control of packaged products. In t h i s connection it may again be of i n t e r e s t t o note the vas t quant i ty of these types of products produced. From the information presented e a r l i e r I have estimated t h a t the federa l ly inspected packers produce i n excess of th ree b i l l i o n consumer s i z e packages year ly .

These packages must comply w i t h the various s t a t e and f ede ra l regulations. For example, M.1 .D . requires :

(1) The average n e t weight of the product checked should equal a t l e a s t the s t a t ed ne t weight.

(2) There should be a s many overweight packages a s under- weight packages.

In addi t ion, M.I.D. ins t ruc t ions t o t h e i r inspectors state, "systematic controls s h a l l be maintained a t a l l times t o check the quant i ty of contents. It is not p r a c t i c a l t o s t a t e d e f i n i t e l y how many u n i t s per hour o r per carton should be weighed o r measured, owing t o many var iable f a c t o r s . Inspectors, however, must assume the respons ib i l i ty of t h i s labe l ing t o the f u l l e s t extent , making such tests a s a r e necessary." is in te res ted only i n assuring that the product is a t marked weight a t the t i m e it leaves a f ede ra l ly inspected establishment.

M.I.D.

O f g rea te r concern t o an interstate packer are the s t a t e weights and measures laws. Fortunately, the National Conference of Weights and Measures i s making considerable progress i n obtaining uniformity among the various states both i n t h e i r s t a t u t e s and i n the regulations promulgated t o implement these s t a tu t e s .

A typ ica l s t a t e l a w would read i n pa r t a s follows:

"It is unlawful t o keep f o r the purpose of sa le , o f f e r o r expose f o r sale, o r sell , any commodity i n package form unless the n e t quant i ty of the contents be p l a in ly and conspicuously marked on the outs ide of the package,

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i n terms of weight, measure o r numerical count; provided, however, t h a t reasonable var ia t ions or tolerances shal l be permitted, and t h a t these reasonable var ia t ions o r tolerances and exemptions s h a l l be establ ished by ru les and regulations made and promulgated by the Department of Agriculture .I'

The National Bureau of Standards has developed model regulations f o r checking pre-packaged commodities which define the method by which packaged products a r e t o be checked t o determine compliance with the law. Again, many s t a t e s have adopted these model regulations and it i s hoped t h a t a l l w i l l do so i n the near fu ture . The model regulation presents a method of control of pre-packaged commodities f o r use by s t a t e and l o c a l weights and measures o f f i c i a l s which is based on two concepts:

"(1) Variations i n quant i t ies of packages a re not 2ermitted t o such extent t h a t the averages of the quant i t ies i n the packages comprising a l o t shipment o r del ivery is below the quant i ty s t a t ed and an unreasonable shortage i n any individual package i s not acceptable even though overages i n o ther packages i n the same l o t shipment o r del ivery compensate f o r such shortages."

" (2 ) Perfection i n e i t h e r mechanical devices o r human beings has not ye t been a t t a ined : thus the existence of imper- f ec t ion must be recognized and allowances f o r such i m - perfect ion must be made. i n t h e average concept."

These allowances a r e recognized

The majority of the weights and measures regulations then require t h a t the average weight of a sample of product obtained i n the r e t a i l s t o r e must equal the marked ne t weight and t h a t there should be no unreasonable underweights. as defined i n the model regulation. However, f o r purposes of i l l u s t r a t i o n an unreasonable underweight on a one lb. package i s one which i s more than 1/4 o z . l e s s than marked weight.

An unreasonable underweight i s proportional t o package weight

I n s e t t i n g up a s t a t i s t i c a l quant i ty control system it is f irst necessary t o determine the inherent v a r i a b i l i t y of the process before estab- l i s h i n g the average o v e r f i l l . However, there a r e other important f a c t o r s which must be considered i n designing the system. know the shrink o r loss i n weight which the product w i l l experience between the time of packaging and the t i m e of sa le , and o v e r f i l l an addi t ional amount t o compensate f o r it. age of the product, the shelf-life of the product and the average age a t which the product i s sold are addi t iona l f ac to r s t o be considered.

For example, one must

Since shrink i s normally proportional t o the

Invest igat ion of these f ac to r s of ten leads t o the development of improved packages t o reduce the quant i ty of shrink f o r which it i s necessary t o o v e r f i l l . s u l t s . For example, a t Oscar Mayer & Co., w e were ab le over a period of time t o reduce the shr ink charac te r i s t ics , and therefore the o v e r f i l l , of our former " t r ay s tyle" bacon carton t o an acceptable leve l , but w e a n t i c i - pated a f u r t h e r reduction i n o v e r f i l l upon conversion t o the new saranpac

However, package changes may be accompanied by unforeseen re-

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vacuum package. tween the film and the bacon, as a result of the vacuum employed, caused a film of bacon fat to cling to the film when the package was opened. The amount of product adhering to the package more than offset the savings in reduced shrink, and we actually had to increase our overfill slightly over our standard for the previous package.

We were surprised to learn that the intimate contact be-

In addition to the moral and legal obligations of providing f u l l stated weight to our customers, there are also important economic considera- tions. For example, if because of lack of control, the meat processing in- dustry were to include 1/32nd 02. (.06 of a pound) extra in the 3,000,000,000 lbs. of processed meats produced annually, it would cost the industry 24,000,000 lbs. o r an estimated $9,500,000 yearly.

In an individual company the installation of a statistical quantity control program invariably provides substantial savings as well as increased protection. sult of the application of S.Q.C.tO pre-packaged product weights approxi- mately 15 years ago, were sufficient to pay f o r the additional help required to perform the statistical quality control, and the entire quality control program as well.

In the case of my own company, the savings obtained as the re-

In addition to quantity control, statistical procedures are used in quality control as well. we are dealing with techniques which relate to attributes. systems are very important in the quality control field as they provide the opportunity to express subjective product characteristics in numerical terms. Usually these are in terms of defects, percent defective or demerits. The demerit systems are cormally employed when defects of different degrees of seriousness are being considered. For example, the defects which normally occur in a given product are often classified as critical, major or minor, and are assigned appropriate demerit weights.

Similar principles apply except in this case Attribute

In setting up a quality control system based on attributes it is necessary for the sales o r marketing divisions to interpret the relative seriousness of the known defects in terms of their possible effect on the sale of product. limits. These defects are associated with such factors as quality character- istics of the meat product itself, workmanship factors in assembling the package and packaging characteristics.

Standard levels are then drawn up with appropriate control

The following slides illustrate how meat quality, workmanship and packaging defects are defined in cooperation with the sales department. first slide demonstrates the maximum amount of internal fat which is per- missible on the cut surface of a boneless half ham. The next slide shows the maximum amount of smearing of pork sausage which is allowable. third slide illustrates a workmanship defect - in this case a critical shingling defect on sliced bacon.

The

The

In addition to assuring the production of a uniform product at the desired quality level, the employment of statistical quality control techniques can also provide valuable information for in-process control by identifying factors which require corrective action, and by providing a measure of the effectiveness of the action taken. An example of this type of application would be the analysis of packaging rejects to determine the

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frequency of the various causes. each cause and control l i m i t s calculated.

A standard frequency can then s e t up on

S t a t i s t i c a l qua l i t y control data of ten provides a bas is f o r making improvements i n the qua l i t y of the product when designing new equipment. In my own company, the design of new continuous wiener processing equipment is a case i n point . Conventionally produced wieners a r e subject t o an un- des i rab le degree of weight, color, length and diameter var ia t ion . Also, a ce r t a in number of the wieners have marks where they hang over the smoke s t i c k s and we a r e not always ab le t o ge t our production workers t o place these wieners i n the package with the s t i c k marks down.

In t h e new continuous processing u n i t the product uniformity has been much improved t o the point t h a t the weight i s controlled exclusively by sampling and s t a t i s t i c a l qua l i t y control, and it i s not necessary t o have a s ing le sca l e i n the production l i n e . Color var ia t ion has been eliminated, as has s i z e var ia t ion , and there a re no s t i c k marks.

S t a t i s t i c a l qua l i t y control techniques can a l so be usefu l ly applied i n the slaughtering, cu t t ing and boning operations. These systems may be based on e i t h e r var iables o r a t t r i b u t e s depending on the pa r t i cu la r appl icat ion. t o be measured o r compared, and then set up the frequency of the sampling i n order t o gain the degree of control required.

A l l t h a t is required is t o f irst define the f ac to r s which are

Typical examples of the appl icat ion of s t a t i s t i c a l qua l i t y con- t r o l on the k i l l i n g f l o o r might include checks f o r effect iveness of immo- b i l i z a t i o n , accuracy of s t icking, s p l i t t i n g of carcasses, head trimming, e t c .

On the cu t t ing f loo r , S.Q.C. techniques have been used t o control the point of divis ion of the carcass between the shoulder and the remainder of the carcass, between the ham and the remainder of the carcass and be- tween the be l ly and l o i n fatback portion. accurately, s ince there is ce r t a in l a t i t u d e i n the posi t ion a t which the cut can be made, and of ten the difference i n value between the primal cuts on e i t h e r s ide of the l i n e of divis ion makes it advantageous to favor one port ion over another.

It is desirable t o make cuts

T h i s point is i l l u s t r a t e d by the following s l i d e :

Here you see a 200/ZlO No. 1 hog w i t h a value of $22.50/cwt. l i v e . On the market that was i n e f f e c t a t the t i m e t h i s slide was pre- pared, the various primal cu ts had the values shown. You w i l l note t h a t there i s considerable difference between the value of the l o i n and the ham which l i e on e i t h e r s ide of the l i n e separating D and G. There i s an even grea te r difference between the value of the Boston b u t t and the l o i n which l i e on either side of the l i n e separating B and D. by these l i n e s can be var ied within ce r t a in qua l i t y l imi ta t ions and it is economically desirable t o ca lcu la te the cu t t ing procedure which w i l l achieve m a x i m m value and then control the d iv is ion at the desired points . S.Q.C. procedures can be used very nicely t o control t h i s s o r t of opera- t i on . In t he i l l u s t r a t i o n shown the ham would be favored over the l o i n inasmuch a s the ham sect ion coverts t o ham a t approximately 90 percent

The cuts represented

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whereas the y i e ld of l o i n from the l o i n sect ion is about 50 percent. the l o i n would be favored over the Boston b u t t . Therefore, i n t h i s case we would cut a so-called long ham and shor t shoulder.

Further,

Other u se fu l appl icat ions of S.Q.C. a re i n the control of ham trimming, ham shank lengths , l o i n trimming, b e l l y trimming and weight grad- ing.

b v i n g through the slaughtering operation t o boning and defa t t ing , S.Q.C. p r inc ip les have been used t o control such things a s cleaning of bones, presence of small bone fragments o r other undesirable materials i n sausage trimmings and trimming of primal cu ts f o r such f ac to r s as depth of f a t , beveling of the f a t , percent of co l l a r , e t c .

S.Q.C . pr inc ip les a r e a l s o used i n the meat industry t o a s s i s t i n purchasing decisions and t o control processes on the basis of laboratory and ana ly t i ca l r e s u l t s . Applications of t h i s type include control of the composition of trimmings by blending, and periodic sampling and analysis , with the use of appropriate control l i m i t s . used i n checking the purchases of trimmings from other suppl iers . case random samples a r e drawn from purchased loads and a s t a t i s t i c a l accept- ance sampling plan employed t o determine whether the purchased l o t i s acceptable o r re jec tab le . of non-meat ingredients and supplies such a s cans, packaging mater ia ls and the l i k e .

Analysis of trimmings i s a l so In t h i s

Similar plans a r e i n use t o control the purchase

The meat inspection divis ion is a l so increasing t h e i r use of ana ly t i ca l controls and they are pa r t i cu la r ly interested i n cases where o f f - premises analyses can be made t o check the effect iveness of t h e i r on s i te inspection. A s the M.I.D. moves i n t h i s d i rec t ion , industry i s i n many cases cooperating t o help develop the necessary ana ly t i ca l re la t ionships , but is i n s i s t i n g t h a t M.I.D. take f u l l recognition of the v a r i a b i l i t y of many of the meat products and employ appropriate s t a t i s t i c a l l i m i t s . For example, a system t o control added water i n sausage products was worked out j o i n t l y by industry and M.I.D. several years ago. This control procedure has worked very wel l w i t h a minimum of d i f f i c u l t y on e i t h e r side because the s t a t i s t i c a l limits employed allow f o r the unavoidable var ia t ion inherent i n sampling and analysis of the product.

On the o ther hand, the control procedures i n e f f e c t f o r cured and smoked pork products have been i n almost a constant s t a t e of flux and have been a source of i r r i t a t i o n t o both the M.I.D. and industry because of dis- sa t i s f ac t ion with the system on the p a r t of both groups. s a t i s f a c t i o n stems from the f a c t that M.I.D. was l o a t h t o permit the proper s t a t i s t i c a l l i m i t s - mainly because these products vary much more widely than sausage products, and, hence, the l i m i t s appeared t o be too wide t o the

Industry's d i s -

M.1.D.

I have a s l i d e which shows the system present ly i n e f f e c t f o r canned hams and which represents t he type of controls employed f o r a l l cured and smoked pork products. I n t h i s case, a ham analyzing between + 4.0% added substance may move f r e e l y whereas r e s u l t s of 4 . 1 t o 5.1 re- qu i re t h a t t he process be immediately corrected t o reduce the added sub- stance.

- If t h e analysis i s over 5.1 added substance the product is

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re ta ined . If the average does not exceed 1.8 added substance the product may move f r ee ly ; if it f a l l s between 1 . 9 and 2.3 the process must be corrected, and if it exceeds 2.3 the product i s retained.

Similar l i m i t s a r e i n e f f e c t f o r a running average of 5 samples.

This system i s based on a study conducted j o i n t l y by industry and the M.I.D. from which a within l o t standard deviation of 3.5 was calculated. A comparison of t h i s value with the out-of-control point of 5.1 i l l u s t r a t e s the reason f o r industry's d i s sa t i s f ac t ion with t h i s control procedure.

I n summary, I would l i k e t o emphasize t h a t while s t a t i s t i c a l qua l i t y control procedures a r e important i n control l ing the operations t o which they a r e applied, they are perhaps even more valuable because of the information which they provide f o r management decision. word "management" implies control . t i o n unless he has accurate knowledge of the output of h i s operation and the a b i l i t y , by decision, to a l t e r h i s output by a predetemined amount. S t a t i s t i c a l qua l i t y control techniques readi ly provide t h i s type of control a t a minimum of expense.

I bel ieve t h a t the No manager i s t r u l y managing h i s opera-

DR. ROBERT SAFFLE: Thank you, Don, I think t h a t a l l of us now have a much b e t t e r understanding of many of the appl icat ions of S t a t i s t i c a l Control and you have stimulated our thinking along t h i s l i n e i n t o addi- t i o n a l areas. I th ink one of the things t h a t come i n t o s t a t i s t i c a l control i s t h a t we must have means of measuring, which Don has indicated, and our next speaker i s t o cover some of the methods of measuring the chemical analysis of products considering the var ia t ions . Dr. W. A. Landmann w a s t o cover t h i s , he w a s with the A.M.I.F. and now i s Keat Chemist a t Texas A & M and, unfortunately, due t o a death i n the family, could not be here with us. However, Professor Robert Hostetler from Texas A & M i s here t o give h i s paper. Robert Hostet ler received h i s M. S. degree a t Purdue University and he i s now on the s t a f f of Texas A & M. The subject t o be covered i s "Methods of Sampling Various Neat Ingredients with Respect t o Accuracy, Precision and Limitations of Rapid Methods t o Determine Moisture, Fat and Protein". Obviously, t h i s i s a broad subject and could not be covered f u l l y i n the t i m e period. In our correspondence, w e agreed t o t r y t o cover as much as possible but t o only emphasize one or two spec i f ic examples. Professor Hostet ler .