Bacterial Quality of some Dessert Toppings

Materials and MethodsOne hundred and twenty-five imitation dairy des­

sert toppings and forty real dairy dessert toppings,purchased in retail markets in Guelph, Ontario, Ca­nada, during the summer Inonths of 1970 were ana­lyzed. The samples represented nine separate brandsof product and consisted of powdered dessert toppingbases, frozen pre-whipped imitation dairy dessert top-

185

One hundred and twenty-five imitation dairy toppings andforty real dairy toppings \vere examined for total place psychro­trophic, colifonn and enterococci counts, and for the incidence ofstaphylococci and salmonellae. All samples were free of salmonel­lae and coagulase positive stalPhylococci. Five (3.03%) of the165 samples had a total plate count of > 1000/g. The psychro­trophic count for all samples averaged < 10/g. Twelve percentof the samples were contaminated with coliforms and 11.5% withenterocooci. A comparison of aerosol containers of imitation dairytopping revealed that 5.0% of the imitation dairy topping sampleswere coliform positive as opposed to 0.0% of the real dairy top­pings. In addition 30% of the imitation samples contained en­terococci as compared to 7.5% of the samples of real dairy top­ping. The total plate counts and psychrotrophic counts for theseproducts were similar.

Cent vingt cinq garnitures artificielles et quarante garnituresfaites de produits laitieis naturels furent examinees bacteriolo­giquement quant au comptage total, au comptage de psychro­trophes, des colibacilles et des enterocoques en plus de l'incidencedes staphylocoques et des salmonelles.

Les echantillons etaient tous libres de salmonelles et destaphylocoques a coagulase positive. Cinq (3.03%) des 165, echan­tillons avaient un nombre de bacteries total au dessus de 1000/g.Le nombre de psychrotrophes pour tous les echantillons montraitune moyenne de moins de 10/g. 12% des echantillons contenaientdes colibacilles et 11.5% contenaient des enterocoques.

5% des garnitures artificielles en bocal aerosol contenaientdes colibacilles alors qu'aucune des garnitures faites de produitslaitiers n'en contenait. 30% des garnitures artificielles contenaientdes entereocoques en comtparaison de 7.5% des garnitures faitesde produits laitiers. L'enumeration totale et Ie nombre de psy­chrotrophes etaient identiques pour les deux genres de garnitures.

Imitation dairy dessert toppings have becomea popular item on the consumer market in recent years.However, published information regarding the bac­terial qualities of these products is difficult to find.Smutz et ale (1969) have reported on the microbiologyof similar products that are available on the UnitedStates market. The present paper report.s on the mi­crobiological quality of imitation dairy dessert top­pings. Aerosol packed whipped cream was includedin the analyses to allow comparison of the real dairyproduct with the imitations. As there were no frozenpre-whipped dairy products nor powdered whippedcream bases available to the consumer, the comparisoncould not be extended to these areas.

Can. Inst. Food Technol. J. Vol. 4, No.4, 1971

Results and DiscussionSalmonellae or coagulase positive staphylococci

were not found in any of the 165 samples analyzed.Coagulase negative staphylococci were isolated fromonly 2 samples of powdered product (10jg and 15/g,respectively). The ranges and average total platecounts and psychrotrophic counts are shown in Table1. Five samples had total plate counts of > 1000/g.The remainder of the samples showed counts ,vhichwere considered to fall within acceptable limits. Thecoliform and enterococci counts are presented in Table2. Twelve per cent of the samples were contaminatedwith coliforms and 11.5% with enterococci. The ratherhigh incidence of contamination with these organismswas disturbing as this is generally accepted as evi­dence of unsanitary conditions during processing.

The sampling of real dairy dessert toppings in

C. L. Duitschaever, D. R. Arnottand D. H. Bullock

Department of Food ScienceUniversity of Guelph

Guelph, Ontario

pings and real dairy toppings. All products weretransported from the retail markets to the labora~orywithout refrigeration to simulate consumer handlIng.Frozen products were allowed to thaw.at 4°0 for 24hours,prior to sampling. Aerosol contaIners and pow­dered preparations ,vere maintained at 4°0 and atroom temperature, re.spectively, and were examinedwithin 24 hours of purchase. Eleven grams of eachproduct were ,veighed into a sterile waring blendorand mixed with 99 ml of buffered sterile water (pH7.2). From this dilution further dilutions of 10-2 and10-3 were prepared. Aseptic sampling and mixing werecarried out on a "Pure Aire" clean bench. Standardmethods (1967) were followed for the total plate countand for the enumeration of the psychrotrophic bacteria.Violet Red Bile Agar (Difco) was used for the de-tection of coliform organisms. Incubation was carriedout at 37°0 for 24 hours. Enterococci were enumeratedon Reinbold's (1953) Blue Tetra~olium-OitrateAzidemedium. Baird-Parker medium wa.s used for the iso­lation of staphylococci. Plates were incubated for 24hours at 37°C. Colonies, if present, were streaked onplate count agar and further examined by gram stainand for coagulase by the slide method (Baker, 1962)with the use of lyophylized bacto-coagulase plasma.(Difeo)

Isolation of salmonellae ,vas attempted by trans­ferring 10 g of sample to 100 ml of Selenite OystineBroth and to 100 ml of Tetrathionate Broth. Follow­ing incubation at 37°0 for 48 hours, a loopful of eachenrichment broth culture was .spread on Brilliant­Green Sulfapyridine and Salmonella-Shigella Agar.The plates were incubated at 37°C and examined forthe presence of typical colonies after 24 and 48 hours.Since no typical Salmonella colonies were found, fur­ther verification by use of determinative biochemicaltests was not carried out.

Resume

Abstract

Introduction

Table 2. Colifonn and enterococci counts of various dessert top pings

Products

Frozen pre-whip­pedPowdered desserttoppingAerosol imitationdairyAerosol real

No. No. Coliforms/g No. Enterococci/gsamples coliforms enterococci

positive Range Average positive Range Average

42 6 <2-43 17 0

63 13 <2-2300 (a) 10 <10-45 16

20 1 4 4 6 <10-25 13

40 0 <2 3 160-1800 721

<10

<10

<10

AverageRange

<10

<10-10

<10-25

No. Total count/g Psychrotrophs/gsamples

<10 <10

One real dairy topping had a total count of > 100,OOO/gWithout this sample, the average was 271.

(a)

References

Products

Range Average

Frozen pre-whipped 42 < 10-1100 197Powered desserttopping 63 15-2600 312Aerosol imitationtopping 20 55-370 162Aerosol realdairy topping 40 <10->105 (a)

American Public Health Association, 1967.Standard methods for the examination of dairy products. 12thedition American Public Health Association, New York.

Baker, F. J. 1962.Handbook of Bacteriological Technique. Butterworth and Co.(Publishers) Ltd. London: 88 Kingsway, W.C.2.

Reinbold, G. W., Swern, M. and Hussong, R. V. 1953.A plating medium for the isolation and enumeration of entero­cocci. J. Dairy Sci. 36:1.

Smutz, Cynthia A., Foltz, V. D. and Mickelsen, Ross. 1969.Microbiology of inlitation and filled dairy products and theircomponents. J. Milk Food Techno!. 32 :446.

Received Apr. 15, 1971.

Two samples contained 2200 and 2300 coliforms/g, the remainder ranging from 10 to 62/g with an average of 14/g. --..~"

Table 1. Total and psychrotrophic counts of pre-whipped aerosolpacked and powdered dessert toppings

(a)

aerosol containers as a comparative study gave a gen­eral indication that the sanitation procedures in pro­cessing the real dairy products were superior to thoseused in preparing the imitation products. The realdairy products contained no coliforms, while 5% ofthe imitation products were contaminated. The entero­cocci counts were of a similar nature, with the realdairy products showing 7.5% of the samples beingpositive as opp'osed to 30.0% for the' imitation dairyproducts.

The total count (Table 1) for aerosol packedimitation products and the real dairy products "Jassimilar. The counts ,vere generally low. The p-sychro­trophic counts for both types of products averaged< lO/g (Table 1).

Although the products analyzed in this studywere generally of good bacteriological quality, furthersurveillance of imitation dairy dessert toppings is de­sirable. Particular emphasis should be placed onthe detection of coliforms and enterococci as a methodof evaluating" sanitary processing procedures.FIGURE LEGENDS

AcknowledgementsThis work was funded by the Department of Agri­

culture and Food of Ontario. The authors wish tothank Mr. Henk Tenoever for carrying out the ana­lyses.

J. lnst. Can. Techno!. Aliment. Vo!. 4, No 4, 1971 186