Controlling Factors

The manufacturing of ambient shelf stable and refrigerated sauces, flavoured oils and salad dressings

Public Protection and Business Support Commercial Food and Safety Tel: 0300 1234 212 Email: [email protected]

Version 3, 2015 Introduction

These guidance notes have been produced to provide informal, best practice advice to manufacturers of refrigerated and shelf stable sauces, flavoured oils and salad dressings etc. to aid them in determining if their product has sufficient safety measures (controlling factors) in place.

This guidance differs from the Food Standards Agency (FSA) vacuum packaging guidance detailed in the useful links section, as it primarily concentrates on the controlling factors and also covers factors to be considered when producing ambient shelf stable products.

Manufacturing of these products commonly involves preparation such as washing, peeling, slicing/chopping, blending; the process may furthermore involve cooking, drying or soaking in brine or acid etc.

With the majority of these products containing some form of fruit, vegetable, herbs or spices, there’s a potential risk of bacteria, including spore formers such as Clostridium botulinum. This guide principally looks at the safety measures to control C. botulinum, as it is a microbiological hazard known to be associated with these products.

C. botulinum

This bacterium is primarily found in soil and has the potential to be present in spore form on vegetables, herbs and spices, which is well established (ACMSF 2003). These products are contaminated during growing and harvesting although good agricultural practices may help to reduce the level of contamination, they cannot prevent it (ACMSF 2003).

The significance of C. botulinum is that it produces a very powerful toxin in food under anaerobic conditions (absence of oxygen) which causes the serious illness botulism, a potentially fatal form of food poisoning. Botulinum toxin is the most potent biological toxin known (Food Standards Agency 2008).

Various outbreaks have been associated with C. botulinum and these types of products (B. A. Nummer et. al 2011):

- 1999, a botulism outbreak in Florida was linked to homemade garlic-infused oil, ingredients included cloves of garlic, rosemary, thyme, and olive oil. - 1998, a case of botulism in the U.S, which was due to home-prepared mushrooms covered in oil. - Between 1994 and 1998, more than 100 cases of botulism reported in Italy have been traced to home-prepared vegetables stored in oil or water.

Controls

Since spores of C. botulinum are widely distributed in the environment, it should be assumed that any ingredient/food might be contaminated.

Washing is unlikely to lower numbers significantly and the cooking process sometimes applied is generally mild and not aimed at destroying C. botulinum spores (ACMSF 2003).

New South Wales (NSW) Food Authority (2008) details two major misconceptions when considering products detailed within this guide:

- The addition of oil has a preservative effect -The only function of the oil is to prevent oxidation from air in the container which can lead to discolouration of some foods. - That some herbs and spices, and especially garlic, have significant anti- microbial properties. These materials possess some preservative effects, however this is relatively low.

Sauces, oils and dressings etc. can be produced safely if they are formulated to ensure that C. botulinum growth is prevented and that any spores present on the vegetables, herbs or spices when added to the oil/placed under anaerobic conditions cannot go on to germinate and produce toxin (ACMSF 2003).

The main controls to prevent the above involve the use of salt, pH, water availability (aW), heat treatment, refrigeration below 3°C or a combination of these (Food Standards Agency 2008). However, as domestic refrigerators cannot guarantee a temperature below this, and the likelihood that storage advice of products may be ignored, refrigeration cannot be considered an adequate control (ACMSF 2003).

This guide therefore concentrates on the following controls, which vary depending on the storage conditions: - pH - Water availability (aW) - Heat treatment - Salt %

Please note this information is for guidance only and manufacturers should initially validate this prior to production, and then verify their product through suitable laboratory tests for: product safety and stability (including yeasts and moulds) and the controlling factor(s) at the given shelf life.

This guide may serve as a starting point to assist in determining if an adequate controlling factor(s) is/are in place, and whether sufficient.

Refer to figure.1 for refrigerated products being kept at or below 8˚C and figure.2 for ambient shelf stable products being stored above 8˚C.

Refrigerated Products (≤8˚C) - Figure.1

Ambient shelf stable products (>8˚C) – Figure.2

Useful links

Food Standards Agency (FSA) vacuum packing guidance https://www.food.gov.uk/business-industry/manufacturers/shelf-life-storage/vacpac

Food Standards Agency (FSA) vacuum packing and modified atmosphere packing food training course http://vacuumpackingtraining.food.gov.uk/introduction/

Public Health England (PHE), formally Health Protection Agency (HPA), Guidelines for assessing the microbiological safety of ready to eat foods on the market https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/3631 46/Guidelines_for_assessing_the_microbiological_safety_of_ready-to- eat_foods_on_the_market.pdf

World Health Organisation (WHO) Botulism fact sheet http://www.who.int/mediacentre/factsheets/fs270/en/

References

1. Advisory Committee on the Microbiological Safety of Food (ACMSF). (2000). Evaluation of the risk of growth and toxin production by Clostridium botulinum in selected new products of concern. Available from: http://acmsf.food.gov.uk/sites/default/files/mnt/drupal_data/sources/files/multim edia/pdfs/acm479.pdf 2. Advisory Committee on the Microbiological Safety of Food (ACMSF). (2003). Home and Commercial Bottling of Vegetables in Oil. Available from: http://acmsf.food.gov.uk/sites/default/files/mnt/drupal_data/sources/files/multim edia/pdfs/Acm636.pdf 3. B. A. Nummer, D. W. Schaffner, A. M. Fraser and E. L. Andress. (2011). Current Food Safety Issues of Home-prepared Vegetables and Herbs Stored in Oil. Food Protection Trends. Vol. 31 (Vol. 31, No. 6,), Pages 336–342. 4. Food Standards Agency. (2008). Food Standards Agency guidance on the safety and shelf-life of vacuum and modified atmosphere packed chilled foods with respect to non-proteolytic Clostridium botulinum. Available at: http://www.food.gov.uk/sites/default/files/multimedia/pdfs/publication/vacpacguid e.pdf 5. Lund, Barbara, Baird-Parker, Anthony C., Gould, Grahame W. (2000). Microbiological Safety and Quality of Food. 6. New South Wales (NSW) Food Authority. (2008). Shelf stable acid preserved foods. Factors affecting the shelf stability of acid foods, condiments, sauces and salad dressings. Available from: http://www.foodauthority.nsw.gov.au/_Documents/science/shelf-stable-acid- preserved-foods.pdf

Glossary < Less than

≤ Less than or equal to

> Greater than

≥ Greater than or equal to aW Water activity, aW represents the ratio of the water vapour pressure of the food to the water vapour pressure of pure water under the same conditions and it is expressed as a fraction

Acknowledgment

Andy Elliot, Public Health England is acknowledged for providing guidance, support and for reviewing the information given above.

If you would like this information in another format please contact:

Cornwall Council Offices, Unit 6, Threemilestone Industrial Estate, Truro, TR4 9LD Telephone: 0300 1234 212 www.cornwall.gov.uk

ProducedEmail: [email protected] by Steven Gorniak, Environmental Health Officer www.cornwall.gov.uk