RALPH W. JOHNSTON of Agriculture

Transcription

1 I MICROBIOLOGICAL CRITERIA I N PROCESSED MEATS* U S RALPH W JOHNSTON of Agriculture Department The s u b j e c t matter which I w i l l b r i e f l y d i s c u s s today i s f a r from being new Microbiological c r i t e r i a have been used f o r q u a l i t y c m t r o l purposes f o r years by many meat processing firms Additionally, t h e s a f e t y of many meat processing procedures has been e s t a b l i s h e d through microbiological r e s e a r c h Federal, S t a t e and l o c a l food r e g u l a t o r y agencies have h i s t o r i c a l l y taken a c t i o n on those microbiological f i n d i n g s which i n d i c a t e a c l e a r hazard t o h e a l t h For example, food products containing b o t u l i n a l t o x i n, staphyloccal enterotoxin o r salmonellae have r e s u l t e d i n s e i z u r e s, i n d u s t r y r e c a l l s and even public r e c a l l s I n v e s t i g a t i o n s of t h e causes of t h e s e i n c i d e n t s i n e v i t a b l y p o i n t t o a breakdown i n handling c o n t r o l s a t t h e food s e r v i c e l e v e l o r f a u l t y d i s t r i b u t i o n p r a c t i c e s 3r improper processing a t t h e p l a n t l e v e l The g o a l of a l l food processors, food microbiologists and food s c i e n t i s t s i s t o prevent these i n c i d e n t s F a u l t y p r a c t i c e s i n t h e home are n o t regulated, thus improvement i n t h i s a r e a i s an educational problem Improper p r a c t i c e s i n t h e d i s t r i b u t i o n and r e t a i l i n g a r e a a r e p a r t i a l l y regulated by a myriad of agencies;again, however, educational e f f o r t s t o e s t a b l i s h and enforce food handling codes appear t o be t h e most e f f e c t i v e c o r r e c t i v e a c t i o n A t the fodd processing l e v e l, t h e use of microbial c r i t e r i a appear t o be an e f f e c t i v e means of improving t h e microbial q u a l i t y of a product and thereby decreasing t h e p o s s i b i l i t y of h e a l t h hazard i n c i d e n t s This includes t h e determination of t h e so-called s a n i t a r y i n d i c a t o r b a c t e r i a as an adjunct t o v i s u a l inspection of f a c i l i t i e s and s a n i t a r y p r a c t i c e s A t t h e food processing l e v e l, it i s more important t o analyse f o r t h e so-called s a n i t a r y i n d i c a t o r s than f o r pathogenic o r toxigenic b a c t e r i a The l a t t e r are normally not p r e s e n t, thus a g r e a t amount of negative d a t a c m l d mislead t h e q u a l i t y c o n t r o l s u p e r v i s o r S a n i t a r y i n d i c a t o r s are o f t e n present and provide p o s i t i v e f i n d i n g s t h a t change on a day t o day b a s i s These f i n d i n g s a l s o can be used t o compare d i f f e r e n t processors, d i f f e r e n t geographical problems, and d i f f e r e n t l e v e l s of i n s p e c t i o n a l activity For most meat products, t h e s a n i t a r y i n d i c a t o r b a c t e r i a include determinations f o r t h e l e v e l s of aerobic p l a t e count, coliform g r m p, E c o l i and S aureus Microbiological c r i t e r i a d e f i n e t h e l e v e l s D f t h e s e organi&s t h a t a r e associated with a s p e c i f i c product o r c l a s s of products produced under good manufacturing conditions I n order t o e s t a b l i s h such c r i t e r i a, a g r e a t amount of l a b o r a t o r y work must be done on t h e s p e c i f i c commodity i n question I t is impossible t o use t h e same m i c r o b i o h g i c a l c r i t e r i a f o r both d r y fermented sausage and cooked bologna * Presented a t t h e 26th Annual Reciprocal Meat Conference of t h e American Meat Science Association, 1973

2 257 The processes and t h e normal b a c t e r i a l e v e l s of t h e s e two products d i f f e r s i g n i f i c a n t l y It i s a l s o hpossibh3 t o apply t h e same microbiological c r i t e r i a t o f r e s h l y prepared luncheon meat and t h e same product held i n t h e r e f r i g e r a t o r f o r s e v e r a l weeks I n t h i s case, we a r e measuring t h e growth of psychropilic b a c t e r i a during t h e r e f r i g e r a t i o n period r a t h e r than t h e s a n i t a r y conditions under which t h e product was prepared For t h e s e reasons, most of our microbiological q u a l i t y work has been done on meat products a t t h e point of production I n newer terminology, t h i s i s a microbial evaluation a t a very important c r i t i c a l c o n t r o l p o i n t Recently, we have been surveying t h e production of cooked meat and gravy products The r e s u l t s of t h i s study i n d i c a t e how background i n f o r mation i s obtained and t h e v a r i a t i o n s i n b a c t e r i a l l e v e l s t h a t were found The products sampled included s l i c e d o r diced meat and gravy, s l i c e d o r diced p o u l t r y and gravy, and meat p a t t i e s and gravy; s l i g h t l y more than 5 6 of t h e samples were s l i c e d beef and gravy I n some cases, t h e meat and gravy was t h e m a i n course portion of frozen prepared dinners I n a l l cases, t h e meat and t h e gravy were cooked separately, c h i l l e d separately, and then combined along a filling-packaging l i n e p r i o r t o f r e e z i n g This survey does not include those meat and gravy products which a r e cooked i n combination, packaged h o t, and t r a n s f e r r e d t o a f r e e z e r while s t i l l h o t T h i r t y four high volume producers were v i s i t e d The firms were located throughout t h e country A t o t a l of 541 production l i n e samples and 535 f i n i s h e d, frozen product samples were c o l l e c t e d and analyzed Each s e t of samples included samples of a l l ingredients used in t h e product, samples a t each s t a g e of processing, and u n i t s of t h e f i n i s h e d frozen product r e l a t e d t o t h e production l i n e samples I n most cases, 1 f i n i s h e d product u n i t s per s e t were c o l l e c t e d Each s e t of samples w a s placed promptly i n a f r e e z e r o r under dry i c e and shipped frozen t o t h e laboratory f o r microbiological a n a l y s i s Generally, t h e a n a l y s i s w a s begun two t o f o u r weeks a f t e r collection During t h e v i s i t s t o t h e firms, s a n i t a r y p r a c t i c e s were evaluated visually Observations were made w i t h respect t o : 1 The personal hygiene of t h e food handlers 2 The cleaning and s a n i t i z a t i o n regimen of food contact surfaces including i n t e r i o r areas such a s gravy l i n e s 3 The times and temperatures t o which t h e products had been exposed prior t o freezing The laboratory r e s u l t s of t h e survey a r e shown i n t a b l e 1

3 TABLIE 1 MEAT AND GRAVY INDICATOR ORGANISMS, GOOD PRACTICE Analysed Number of samples Posit i v e ~ 8 positive ~ Coliform group E c o l i S - -aureus Salmonella 375 O f t h e 375 f i n i s h e d product u n i t s produced under good commercial p r a c t i c e s, 288 (77%)were coliform negative, 359 (96%)were E c o l i negative, 349 (93%)were S aureus negative and a l l were negative f o r salmonellae When p r e s e n t, these i n d i c a t o r organisms were a t l o w l e v e l s Coliforms were recovered only i n 1 g p o r t i o n s from 7 of t h e 87 coliform coli positive positive units; E - -c o l i only i n 1 g p o r t i o n s from t h e 16 E u n i t s ; and S aureus only i n 1 g p o r t i o n s from 22 of t h e 56 S aureus p o s i t i v e u n i t s Only one u n i t each was p o s i t i v e f o r c o l i f o r m s a n d S - aureus a t the 1 g p o r t i o n TABLE 2 MEAT AND GRAVY INDICATOR ORGANISMS, MARGINAL PRACTICE Analysed Number o f samples Positive Coliform group E c o l i S aweus Sa h o n e 1l a 16 % positive

4 259 O f the 16 finished product units produced under marginal commercial p r a c t i c e s, t h e percent p o s i t i v e u n i t s increased, 74$ were coliform p o s i t i v e, 42$ were E, c o l i p o s i t i v e and 13%were 2 aureus p o s i t i v e These r e s u l t s represent t h e production fran 9 firms a s opposed t o t h e previous f i g u r e s which represented 32 firms A l l finished product u n i t s (535) were salmonellae negative i n 25 g portions Only 2 of t h e 541 ingredient and production l i n e samples were salmonellae positive; one sample was cooked beef llscrapsll collected from under t h e blade of a s l i c i n g machine, t h e other was a hand trimmed raw beef round which had been bagged with g e l a t i n and spices f o r cooking TABLE 3 MEAT AM) GRAVY m R O B I C PLATE COUNTS, GOOD PRACTICE Number of sets analysed < Number of s e t s with APC 1,-5, i,ooo-io,ooo 1, 5,-1, 33 O f t h e 33 s e t s of finished product u n i t s produced under good commercial p r a c t i c e s, t h e geometric means of t h e aerobic p l a t e counts of 27 s e t s (828) were l e s s than lo,ooo/g Only 1 set ( a t 79,OOO/g) was over 5O,OOO/g TABLE 4 MEAT AND GRAVY AEROBIC PLATE COUNTS, MAEEGINAL PRACTICE Number of sets analysed 13 io4-15 K (368) Number of sets with APC (31%) 5%) 2 > 17

5 i / 26 O f t h e 13 s e t s of f i n i s h e d product u n i t s produced under marginal commercial p r a c t i c e s, t h e geometric means of t h e aerobic p l a t e counts of 8 sets (62%) w e r e in excese of 1, 5 TABB Organism MEAT AND GRAVY Good p r a c t i c e $ p o s i t i v e samples Marginal p r a c t i c e E coli S Coliforms aureus Sa lmonel l a This table shows the e f f e c t of manufacturing p r a c t i c e s on t h e incidence of i n d i c a t o r srganisms i n frozen cooked meat and gravy products The f r e s h l y cooked meat and gravy i n g r e d i e n t s do not contain t h e s e organisms and t h e i r presence i n t h e f i n a l product i s a function of t h e degree of recontamination It i s apparent t h a t c l o s e a t t e n t i o n t o s a n i t a r y c o l i, coliforms and p r a c t i c e s limits t h e number of samples containing -S aureus i n t h a t o r d e r E TABLE Level 6 MICAT AND GRAVY Number of sets w i t h APC s i n Marginal p r a c t i c e Good p r a c t i c e 7 1 6

6 261 Table 6 shows the e f f e c t of manufacturing practices on t h e aerobic p l a t e counts i n frozen cooked meat and gravy products The f r e s h l y cooked meat and gravy ingredients contain only very low b a c t e r i a l counts Here again, close a t t e n t i o n t o s a n i t a r y p r a c t i c e s limits t h e contribution of b a c t e r i a from equipment or from time-temperature abuses This survey demonstrates t h a t more than 7@ of t h e s e t s of frozen cooked meat and gravy u n i t s (1 u n i t s / s e t ) produced under good commercial p r a c t i c e had : 1 Four o r fewer c o l i f om-positive u n i t s 2 Two or fewer E - -c o l i - p o s i t i v e u n i t s 3 Three o r fewer S - aureus-positive u n i t s 4 APC (geometric mean o f 1 u n i t s ) of l e s s than 5,OO/g Corrections have been made i n those firms l i s t e d as marginal and a d d i t i o n a l plant v i s i t s a r e underway It appears t h a t corrective compliance i s not t o o d i f f i c u l t t o a t t a i n Further, t h e use of comparative microbiological data, such as t h a t presented today, is an invaluable a i d t o Meat and Poultry Inspection Bacteriological analysis of products samples objectively Program inspectors a t p l a n t l e v e l may d e t e c t t h e need f o r correction of p l a n t p r a c t i c e s t h a t contribute b a c t e r i a t o foodstuffs The d a t a presented today, along with our follow up data, a r e being evaluated by our S t a t i s t i c a l Staff f o r e s t a b l i s h i n g appropriate c r i t e r i a The approach under study, a s developed by t h e I n t e r n a t i o n a l Commission on Microbiological Specifications f o r Foods, has been described by R Paul E l l i o t t i n t h e 1972 Proceedings of t h e Meat Industry Research Conference

7 262 S SIMON: Thank you, Ralph We have time f o r questions or comments Please give name and a f f i l i a t i o n OSTOVAR, PENNSYLVANIA STATE: Since Clostridium perfringens I s the number two organism causing food poisoning i n the U S, I was wondering why you didn't look a t Clostridium perfringens since there has been quite a f e w reports l a t e l y that t h i s organism has been i s o h t e d from gravy7 RALPH W JOHNSTON: A very good point One of t h e reasons i s t h a t t h e organism does not survive well e i t h e r under r e f r i g e r a t i o n or under frozen conditions I f you r e f r i g e r a t e t h e product, it does not grow Another very important aspect of Clostridium perfringens is t h a t i n cooked food products you don't get r i d of t h e organism The spore is heat s t a b l e and survives; therefore, i t ' s meaning as a sanitary indicator i s n ' t quite as c l e a r a s other organisms t h a t a r e more heat s e n s i t i v e OSTOVAR, PENN STATE: Well, here a t Penn S t a t e, we've been looking a t t h e frozen dinners f o r the p a s t year and a half and we've been looking a t Staphylococcus aureus growth and toxin production as w e l l as Clostridium p r f r b g e n s, and we have come across some Clostridium p e r f r i w e n s strains which w e have isolated from gravy R W JOHNSTON: Yes, one problem here i s where d i d they come from Did the organisms came from t h e spices, improper sanitary practices, t h e meat, or equipnent in t h e p l a n t The f a c t is when you have a heat r e s i s t a n t spore a s Clostridium p e r f r i w e n s, unless you determine t h e h i s t o r y of these samples, you have no idea where they came from; therefore, t h e i r association as a s a n i t a r y indicator is of a lower order than non-heat r e s i s t a n t indicator organisms OSTOVAR, PE" STATE: B u t, s t i l l you f i n d them i n t h e f i n a l product? R W JOHNSTON: O h, y o u ' l l f i n d them i n many kinds of products As a matter of f a c t, we have done work which I didn't present here showing that ground crops such a s celery, l e t t u c e and spices frequently contribute Clostridium perfringens Thus, when found i n a cooked i t e m, it i s d i f f i c u l t t o determine whether o r not they were incorporated by the meat, vegetables, o r processing equipment OSTOVAR, PENN STATE: May I have one more question, M r Chairman? I n our studies on Staphylococcus aureus from frozen food items, our counts were much higher t h a n yours I w a s wondering what method you used f o r isolation? R W JOKNSTON: We a r e using b a s i c a l l y t h e AOAC procedure OSTOVAR, P E " STATE: Voge 1-Johnson? R W JOHNSTON: Which medium a r e you using? bird-parker Baird-Parker or

8 V R CAHILL, OHIO STATE: Do you have information regarding the extent of food contamination and l e v e l of t h e human body defense mechanism? R W JOHNSTON: We have sone information with regard t o t h e extent of food contamination o r recontamination P a r t of that was presented today I have no conments and don't w i s h t o get involved with t h e s i t u a t i o n regarding the immune response of t h e human, r e l a t i v e t o these p a r t i c u l a r l e v e l s of b a c t e r i a Basically, we consider those organisms that w e presented today, a t t h e l e v e l s that we presented them t o be q u a l i t y c r i t e r i a, not health hazard c r i t e r i a Throughout t h e study, I m i g h t add t h a t I did not see any single food product t h a t I would consider a n Imminent food hazard S SIMON: Thank you, Ralph Before returning t h e podium t o John Sink, I want t o thank again the speakers f o r their e f f o r t s and t h e contributions they made t h i s morning, and i n addition t o t h e committee, I want t o express our appreciation t o Warren Tauber f o r h i s part i n coordinating t h e a c t i v i t i e s of the processed mats committee with the d e s i r e s of the executive committee JOHN SINK: Thank you, very much, Sy, f o r a f i n e committee report

9 264 JOHN SINK: This morning t h e Continuing Education Committee chaired by D r W C S t r i n g e r w i l l give i t s report B i l l received h i s P h D from Missouri and is currently Associate Professor of Food Science and N u t r i t i o n a t t h a t institution W C STRINGER: Thank you, John I would l i k e t o thank t h e Continuing Education Committee--Dick Epley, Bob Terrell, John Miller, Dixon Hubbard and Dave Schafer f o r t h e i r h e l p and suggestions i n planning t h e program Our first speaker t h i s morning is Mr L e w i s F Norwood, Jr, of USDA Lew has been very a c t i v e i n food marketing and d i s t r i b u t i o n i n t h e Extension Service arld c u r r e n t l y serves as "Leader, Food D i s t r i b u t i o n Program" Lew w i l l now speak on t h e subject, "The Challenge f o r Meat S c i e n t i s t s i n Adult Education "