Microbiological and Chemical Quality of Dips - July-September 1997
July - September 1997
To determine the microbiological status of dairy and non-dairy dips available in the ACT market.
To determine the compliance of dairy and non-dairy dips available in the ACT market to their standard requirements.
Dips are perishable refrigerated products and therefore considered high risk foods. This survey was undertaken to determine the microbiological quality of dips as this product type had not been adequately surveyed in the ACT for the past 5 years and new products have entered the market during this time. Dips were analysed for Standard Plate Count (SPC), Escherichia coli (E.coli) and Coagulase positive Staphylococcus.
Both benzoic acid and sorbic acid are permitted to be used as chemical preservative in these products dependent upon the nature of the product.
Benzoic acid is permitted for use in non-dairy dips where the pH is 4.5 or less. This pH is the most suitable for preserving foods and beverages (Ref 3,4), but such a narrow pH range limits applications in food preservation. Despite this, benzoic acid effectively inhibits the growth of a wide range of fungi and many bacteria. The food additive code numbers for benzoic acid and its associated salts are 210 - 213.
Sorbic acid and its salts are permitted in dairy dips. As a preservative, it inhibits the growth of yeasts, fungi and bacteria over a much wider pH range than benzoic acid and is effective up to a pH of 6.5. In general, sorbic acid and its salts are considered to be one of the safest anti-microbial agents used in food (Ref 3,4). Their food additive code numbers are 200 - 203.
There are no prescribed standards in the Code applicable to dips. Table 1 shows the assigned criteria used by Health officials for this type of product.
|E. coli||< 10||>10|
|Coag +ve Staphylococcus||< 100||>100|
#Units expressed in terms of colony forming units per gram (cfu/gm).
In Standard A3 of the Code - Food Additives, the scheduled permissions for dips includes:
|Food||Additive and Limits|
|Dips containing more than 700 g/kg of dairy products||Sorbic acid in proportion not exceeding 500 mg/kg.|
|Non-dairy dips with a pH of less than 4.5||Benzoic acid in proportion not exceeding 700 mg/kg.|
There were 77 dips collected for this survey during the period July to September 1997. The dairy dips (dips containing more than 700 g/kg of dairy products) were identified by inspecting their ingredients list. Where milk, cheese, or milk solids were listed as primary ingredients they were categorised as "dairy dips". If not, the dips were categorised as "non-dairy dips with a pH of less than 4.5".
Dips are available in many flavors and varieties including French Onion, Sun Dried Tomato, Chick Pea, Corn Relish, Smoked Salmon, Eggplant and Avocado. Some of the less familiar variety samples included Satay & Fruit, Russian Style Caviar Spread, Olive Tapenade with Pesto, Hot Tapenade and Salvio.
Some of the manufacturers of prepackaged dips include Dairy Farmers, Delico Food Products, Kraft Foods Ltd, QUF Industries, Copperpot Pate, Josephines La Gourmet, Poseidon Tarama and Alfresco Providores.
The non-prepackaged dips are mostly locally produced and sold through various supermarkets and delicatessens.
All samples were tested for preservatives. The graph above indicates the usage of preservative for both dairy and non-dairy dips and as indicated, the use of preservatives is more common in dairy dips.
"PRESERVATIVE FREE" labeling is becoming common for these product types. This is non-mandatory, additional labeling being used by manufacturers for market segmentation purposes. For this survey, analytical results show that such labeling can be misleading. Three dairy dips carrying this "preservative free" label were found, upon testing, to in fact contain preservatives. As all were produced by one manufacturer, indications are either a breakdown in production processes or intentional false labeling. Consequently, further investigation is required. For non-dairy dips, 7 samples carried this labeling claim and all were found to comply.
Of the dairy dips tested, 83 % (35/42) were prepackaged and readily available through supermarkets. Twenty one of these samples were listed as containing sorbic acid preservative. Upon testing, 12 were found to have levels above the standard requirement, and the remaining 9 were satisfactory.
The results for the non-dairy dips are also variable. Of the 20 prepackaged dips, the pH was found to be acceptable for all samples except one. This was at pH 4.6, slightly above the standard requirement of pH 4.0. On account of the preservative results, 25% of these samples failed to comply: 3 samples failed to declare preservative use, 1 had used sorbic acid (not benzoic), and 1 was found with excessive amounts of both preservatives - in the order of 800 mg/kg total amount. The remaining 75 % of these samples were acceptable. From the 15 non-prepackaged dips, 14 were preservative free and 1 contained sorbic acid, not benzoic acid as permitted.
The Standard Plate Count (SPC) was performed on 76 samples. Of these, 16 tests could not be included due to atypical bacteria masking the counting. From the remaining samples, 18 % (11/60) had counts above 1 million which is considered unacceptable. This includes 8 non-dairy dips (3 prepackaged and 5 non- prepackaged).
Coag +ve Staphylococcus
All 76 samples tested negative for Coag + Staph. The detection level used is <50 colony forming units per gram (cfu/g).
Of the 76 samples tested, 3 (4%) samples were positive, with counts of 5, 11 and 4 colony forming units/gram (cfu/g). These results are from different samples and different manufacturers and so can be regarded as low and acceptable. All three samples were non-prepackaged dips which strongly indicates that contamination is occurring during production and/or handling and storage of the product.
The SPC gives an overall indication of the initial cleanliness of manufacturing and subsequent storage (temperature) conditions for the life of the product. It is difficult to separate the influence of these two elements on the final SPC level as each will have contributed in its own way to the final SPC.
The majority of samples complied with the standard requirements of preservative use in dips. However, there were some samples with excessively high levels of preservatives and in some instances, the use of inappropriate preservative. This may be explained by manufacturers lack of understanding or knowledge of the food code requirements. Should this be the case, there would seem a need to educate and inform them of the standard requirements.
A feature of this survey was the use of "Preservative Free" labeling on packaged dips. This type of labeling is not mandatory for the manufacturer, however it appears to have become increasingly popular, assumingly to aid consumer choice. From this survey, one manufacturer seems to be using this labeling claim falsely. Three different varieties of dips from this manufacturer tested positive for sorbic acid preservative while clearly indicating a "PRESERVATIVE FREE" claim. Such misinformation clouds a consumers judgment, who may base their selection on such labeling. As a consumer issue, it should be followed up and corrected.
Dips are a popular food item with many manufacturers offering a wide variety of choice to consumers. From the testing undertaken, the microbiological acceptability is generally good with only a few samples having unacceptable SPC levels, while indicating acceptable results for Coag +ve Staphylococcus and E.coli.
Sorbic and benzoic acid preservatives are commonly used in the manufacturing process, and on average, are found in about half the products. Their use is more predominant in dairy dips at approximately 76%, compared to non-dairy dips at 20%. There is generally good compliance to the standard requirements with a few samples identified as not complying due to no labeling, use of excessive levels and/or use of incorrect preservatives. This survey has also highlighted "PRESERVATIVE FREE" labeling claims, and in some cases, these claims are not always accurate.
Refer to recommendations document.
Australia and New Zealand Food Authority, Food Standards Code, incorporating amendments up to and including Amendment 38, April 1998.
Food Act 1992 (ACT), reprinted as at 31 January 1996.
Sofos, JN, Antimicrobial Agents, in: Maga, JA and Tu, AT (eds) Food Additive Toxicology, Marcel Dekker Inc., New York, 1994.
Deshpande SS, Deshpande US, and Salunkhe DK, Food Acidulants, in Maga JA & Tu AT (eds), Food Additive Toxicology, Marcel Dekker Inc, 1994.
Sampling Officers: James Edis, Craig Davies and Susan Payne
Sample analysis: Helen Kivela, Rachel Kennedy, Andrew Rigg, Fiona Wojtas
Report: Simon Christen, Simon Rockliff and Geoff Millard