10 Food Hygiene and Safety at the Retail–Consumer Phase After processing, foods may have numerous stages to go through before reaching the consumer, with the possibility of the food becoming contaminated at any of these stages, e.g. packaging, storage, transport, retail display, and cooking within restaurants and cafes. Food producers, retailers and caterers have a responsibility to supply safe food of good quality to the consumer. However, it is also the responsibility of the consumers themselves to ensure that foods continue to be handled, prepared and cooked in a safe manner. This chapter summarizes the responsibilities of the retailer – and ultimately the consumer – in ensuring food quality and safety. The retail industry covers a wide range of different types of outlets dealing with different types of foods, including butchers, grocers, greengrocers and bakers, supermarkets and catering establishments. In the UK, all those involved in the production of foods – including retail and catering establishments – are governed by The Food Safety Act, 1990. Other pieces of food regulations also exist, related to food-handling establishments excluding abattoirs (Food Safety, General Food Hygiene, Regulations, 1995). In addition, other guidelines are also available, such as various Codes of Practice, the use of Good Manufacturing Practice (GMP) and the use of Hazard Analysis and Critical Control Point (HACCP). However, all the individual food regulations are to be superseded on 1 January 2006, by the new EU Hygiene Regulations (H1–3). These cover regulations for the hygiene of all foods (H1), additional rules for foods of animal origin (H2) and official controls including the tasks of the Official Veterinary Surgeon (H3). These are responsible for providing a wide range of products directly to the consumer, from a wide range of sources. In order to ensure the highest degree of safety and quality, only food items from reputable suppliers should be bought. The food must be properly labelled and packaged, with all packaging intact (particularly tin cans). The temperature of the food upon arrival should be checked to ensure it has not passed an acceptable level, i.e. chilled food <10°C, frozen food <−12°C. If foods have surpassed these temperatures, they should not be accepted onto the premises. Upon arrival at the retail outlet, all foods should be stored at the correct temperature and handled appropriately throughout. During storage, food products will start to lose their quality, as they all have an inherent life-span (meats and dairy being shorter than dry goods), known as the shelf life. The shelf life of a food product can be affected by changes in the environment in which it is stored, the packaging in which it is wrapped, and by internal changes in the food product itself. Environmental factors that can alter the life of food products include: light, oxygen, temperature, moisture levels, pests and chemicals stored near to food products that may cause flavour exchanges. In terms of packaging, there could be certain interactions between the product and the packaging material, with chemicals form the packaging leaching into the food product. The food product itself will undergo various changes over time, such as physical, chemical and biochemical, that can alter food quality. Possibly the most important factor that affects the shelf life of a product is the growth of any microbes present, which can result in spoilage of the food, but also more importantly, a reduction in the safety of the food by the growth of pathogenic bacteria. In order to ensure that the food that reaches the customer is safe and of good quality, in terms of microorganisms, each new product is tested and given a maximum shelf life by the retailer. Batches of samples are tested for bacterial numbers at various stages of storage under controlled environmental conditions. When the food starts to become unacceptable in terms of quality, this is termed the maximum shelf life of the product. If any modifications are made to a food product, the maximum shelf life must be recalculated. Predictive modelling is one tool that can be used to predict maximum shelf life by the retailer. Once the maximum shelf life of a product is known, this has to be displayed on the product in order to alert the consumer – and indeed the retailer – as to when the product should be consumed in order to retain maximum quality and safety. This is known as date-marking, and there are several which can be displayed on a product. The ‘sell-by’ date is for the retailer’s reference only, and enables the vendor to carry out proper stock control. This gives information on the display life of the product. The ‘best-before’ date must be displayed on a product for retail sale. This is the date up to which the product should retain its particular properties when stored under the correct conditions, and is required by UK legislation. The ‘use-by’ date has been determined by the manufacturer of the product and is the last recommended day on which the food should be consumed in order to be of good quality. This date must be used for foods which are highly perishable and likely to pose a risk to human health, e.g. for meats and dairy products. Foods must not be sold once the use-by date has elapsed. When wrapped foods for retail sale are stored under chilled or frozen conditions, they must be solely foods and food products that were delivered to the retail outlet under these conditions. These types of food will be displayed for sale in lit cabinets which should be properly temperature controlled to ensure they do not rise above an unacceptable temperature, i.e. chilled units should operate at <7°C and frozen units at <−18°C, due to customers opening the doors to remove food items. Cabinets should also be placed away from direct sunlight, high-intensity lights and heating units within the retail outlet. The display cabinet should not be overstocked with products and should be stocked only with items at the correct temperature, i.e. frozen or chilled temperatures. The air inlets should not be blocked, and foods that have the shortest shelf life should be placed at the front, i.e. first in, first out. In some retail outlets, such as butcher shops or butcher counters within supermarkets, raw and cooked meats can be displayed and sold together. The biggest risk factor from these types of foods is the cross-contamination of microorganisms between the raw and cooked products. In order to minimize this, a number of good hygienic practices should be observed. The same utensils, knifes and cutting boards should not be used for both raw and cooked products – colour-coded chopping boards can be used to handle raw and cooked products separately. The meat should be displayed in properly chilled cabinets that should be temperature-checked regularly throughout the day. There should be a physical separation between raw and cooked products during display. Staff handling the products should be properly trained in basic food safety and hygiene, and should observe proper hygienic practices throughout. However, the most important practice is to thoroughly wash one’s hands with soap and water after handling raw foods, or after handling money from the customer. Staff can spread microorganisms onto foods due to poor personal hygiene, especially when showing signs of illness. Therefore, staff should not handle foods if they have sickness or diarrhoea or have had those symptoms in the previous 48 h. Food handlers should be free of symptoms for at least 48 h before their return to work. Delicatessen counters sell a wide range of unpackaged, ready-to-eat foods which have a short shelf life – usually 1 working day, such as cooked meats, pies, cheeses and salads. These will be displayed in a chilled cabinet in the same way as the raw and cooked meats above, and hence the same precautions as above should be taken. Again cross-contamination is the biggest risk factor with these foods, and so to reduce this risk separate tongs should be used for each food type, disposable gloves should be worn by the staff and a separate piece of paper should be used on the scales when weighing out each item of food. When replacing food products that have been sold, all of that particular food should be used and then completely replaced – not just topped up. Staff working on this counter should be trained in food hygiene and safety, and should follow the same guidelines as written in the ‘raw and cooked meats’ section. This type of retail outlet is responsible for selling food that has been prepared and cooked on the premises. Some of the points outlined above in the previous retail sections are also relevant here. Only foods of good quality and from reputable sources should be purchased, stored at the correct temperatures and handled correctly throughout. Steps should be put in place to avoid the risk of cross-contamination of raw and cooked products, both during storage and preparation. Staff should carry out all procedures hygienically as described above and be properly trained in food hygiene and safety. However, additional precautions are required as the food is to be prepared and served immediately to the consumer – any improper practices could result in large-scale food poisoning. Hand towels and tea towels are known to harbour microorganisms which can be transferred to the food, and so those should be used appropriately in the kitchen and changed regularly. Once the food item has been purchased from the retail outlet, it is then the responsibility of the consumer to transport, store and prepare the item in an appropriate manner in order to avoid the risk of food poisoning. The home is the only food preparation area where food is not governed by legislation, and consumers handle raw foods that harbour microorganisms without any formal training or education of the dangers. The home is the source for 50–80% of food-borne outbreaks within Europe, and most of the outbreaks of salmonellosis in the UK are attributed to the home. The foods most associated with outbreaks of food-borne disease in the home, according to data from the UK Health Protection Agency, are indicated in Fig. 10.1. The main causes of food-borne outbreaks in the home have been identified as inadequate storage, inadequate cooking and cross-contamination. Food bought by the consumer can be subjected to temperature abuse due to incorrect storage. As discussed earlier, a rise in temperature allows growth of microorganisms, which can result in implications for food safety. In order to minimize this, it is recommended that the consumer pick up chilled or frozen foods last when shopping, and should transport these foods home using a cool bag. A survey of 252 households in the south-west of England showed that only 12.7% of people transport chilled or frozen foods home using a cool bag (Evans et al., 1991). In the same study, the effects of not storing food in a cool box were demonstrated: the temperature reached within an hour by the foods not stored in a cool box (raw chicken, cooked chicken, prawns) reached values (24–37°C) – more than sufficient to support the growth of microorganisms. Fig. 10.1. Food-borne outbreaks from foods consumed at home 1992–1999 (the UK HPA data). Once the chilled food has been transported home it should be placed in the refrigerator as soon as possible, to reduce the likelihood of temperature increase and the time at which the food spends at an increased temperature. In the same survey conducted by Evans et al., the operational temperature of 252 household refrigerators was measured. The range was between 0.9°C and 11.4°C, with an average temperature of 6°C – only 1.6% of the refrigerators operated below 5°C. Nearly all the participants in the study were unaware that the correct operational temperature of a refrigerator is <8°C. The temperature variation within the refrigerators was also measured. The warmest place in 69.9% of refrigerators was the top, and the coolest place was the middle shelf of 45.1% of the refrigerators in the study. Therefore, food will be subjected to varying temperatures depending on which part of the refrigerator it is stored in. This can be due to several factors, such as misreading cooking times and temperatures, food not reaching the core temperature of 70°C, etc., but is increasingly becoming a problem due to the increased use of microwaves. Microwave ovens cook food rapidly, but also unevenly, leaving ‘cold spots’ in the food where bacteria may be able to survive. Food should ideally be stirred half way through cooking to dissipate the heat throughout the product. Another important factor is the standing time of the product, which should be observed, as this is required to complete cooking. Microwave ovens may also be used to defrost foods prior to cooking. If this is the case, the food should be defrosted thoroughly and should then be cooked immediately. In addition to those factors previously discussed in the retail and catering sections, other factors that contribute to cross-contamination within the consumer environment are dishcloths, sponges and tea/hand towels. The same sponge/cloth can be used to wipe several different surfaces, utensils and the refrigerator, within the kitchen as well as to wash dishes. Dishcloths and sponges are then left wet in a warm environment that is ideal for the growth of bacteria. Studies have shown that the bacteria present on dishcloths can increase from 102 to 106 (100–1,000,000) CFU after only 3 days of normal use. Dishcloths do not seem to be changed very regularly and so any bacteria present will increase to large numbers, but can also be spread round the kitchen environment time and time again. A recent study found that 60% of people change them at least once a month, 14% of consumers change their dishcloths every 1–3 months, and 5% of consumers change their dishcloths every 6–12 months. Bacteria such as E. coli, Salmonella spp. and Listeria monocytogenes have all been isolated from dishcloths in previous studies. These organisms will usually be picked up initially from raw food and can then be spread around the kitchen environment. Pathogenic bacteria have been often isolated from kitchen refrigerators. Data from the National Food Centre (Ireland) showed the presence of S. aureus in 40% of domestic refrigerators, Salmonella spp. 7%, L. monocytogenes 6%, E. coli 6% and Y. enterocolitica 2%. Another area of potential cross-contamination in the kitchen is from domestic pets. These animals, particularly cats and dogs, can carry Campylobacter spp., Salmonella spp., E. coli O157, Helicobacter pylori, Toxicara, etc., which can be passed to man (see Chapter 10.5). Pets can spread these organisms by jumping on to food preparation areas, eating from containers used for human food, using utensils used to prepare human food and defaecating within the kitchen area. Hands should be thoroughly washed after handling animals and prior to preparing food, and litter trays should not be kept in the kitchen. Bolton, D.J. and Maunsell, B. (2004) Guidelines for Food Safety Control in European Restaurants. Teagasc – The National Food Centre, Dublin. Evans, G.I., Stanton, J.L., Russell, S.L. and James, S.J. (1991) Consumer Handling of Chilled Foods: A Survey of Time and Temperature Conditions. MAFF, London. The level of microbiological safety of a food portion at the time of consumption is a consequence of several factors. These include occurrence of microbes at the different steps of production, mixing and dividing of lots, contamination, growth and inactivation of microbes, as well as temperatures and time during processing and storage. In addition to the contamination frequency and level, the serving size, method of serving, frequency of consumption, dose–response and the susceptibility of the consumer all affect the microbiological risk caused by food at the time of consumption. Due to this complexity, the safety of a food at the time of consumption is based on multiple events and decisions made throughout the whole production chain. The safety of foodstuffs should be ensured by preventive approach such as product design, implementation of good hygiene practice (GHP) and application of the principles of hazard analysis and critical control point (HACCP) throughout production, processing, handling, distribution, storage, sale, preparation and use. This type of control throughout the whole production chain can assure that the level of protection is met in many circumstances where end-production testing alone realistically cannot. One of the management options available for usage, in order to improve food safety or to verify the safety status of a food lot, is microbiological criteria. However, it should be kept in mind that the microbiological safety of many foods can be assessed by a variety of methods besides microbiological testing (e.g. process or product characteristics). Microbiological criteria cannot be applied without microbiological testing, although testing itself can be used for many different purposes which may or may not be connected to microbiological criteria. The main targets for microbiological testing in food production are: • acceptance of a lot of raw materials, food ingredients or end products; • establishment of shelf life of certain foods; • monitoring of the production lines; • monitoring of the hygienic status of the processing environment; • verification of GHP and HACCP; • baseline studies for the occurrence of specific microbes at a specific step(s) of production; • surveillance at a specific step of production; and • outbreak investigations. According to the definition of the Codex Alimentarius Commission (1997), a microbiological criterion defines the acceptability of a product or a food lot, based either on the absence or presence, or number of microorganisms, including parasites, and/or on the quantity of their toxins/metabolites, per unit(s), volume, area or lot. It can be focused on pathogens, indicator or index organisms, microbial metabolism or specific genetic sequences, and it can be either qualitative or quantitative. Some of the basic terms in the field of microbiological criteria are presented in Table 10.1. Microbiological criteria can be either mandatory or advisory, and they usually fall into three categories: namely standards, guidelines and specifications: 1. Standards (also termed mandatory criteria) are based on legal requirements and may result in reprocessing, rejection or destruction of a lot. 2. Guidelines can be applied during production and processing or on the end products, and they are intended for verification of safe and hygienic production or shelf life, and usually result in corrective actions. 3. Specifications are criteria used for contractual purposes by food businesses. ICMSF (2002) has described these different types of criteria as follows: 1. Microbiological standards are used to determine the acceptability of a food with regard to a regulation or policy. These standards are established by regulatory authorities and they define the microbiological content that foods must meet to be in compliance with a regulation or policy. Foods not meeting the standard are in violation of the regulation or policy and are subject to removal form the market. 3. Microbiological specifications are used by buyers of a food or ingredient to reduce the likelihood of purchasing a product that may be of unacceptable safety or quality. Microbiological specifications can define the microbiological limits for an ingredient so that, when it is used, the final product will meet all the requirements for safety and quality. Buyers throughout the food systems establish microbiological specifications for materials they purchase. In most cases, specifications are advisory and the materials are sampled periodically. When microbiologically sensitive ingredients are purchased, each incoming lot may be sampled and tested. Table 10.1. Some terms defined in the field of microbiological criteria. For a criterion, it must be defined exactly what type of hazard (e.g. Staphylococcus aureus or coagulase-positive staphylococci) and food category, production or processing steps are involved; the sampling plan, the analytical method accepted and the acceptable frequency of positive samples – as well as the consequences from positive test results are all essential components also. There are two widely accepted types of sampling plans: the two-class plan (e.g. n = 5, 10, 15, 20 or more and c usually = 0) and the three-class plan (e.g. n = 5, c = 2, m = 103, M = 104) (ICMSF, 2002). In this notation n is the number of sample units (chosen separately and independently) examined from a lot and c is the maximum allowable number of defective sample units (two-class plan) or marginally acceptable sample units (three-class plan). In two-class plans m separates good quality form defective quality, and in three-class plans good quality from marginally acceptable quality. Consequently, M is used in three-class plans to separate marginally acceptable quality from defective quality. The two-class plan is used mainly for pathogens and/or where a presence/absence test is to be performed, whereas a three-class plan is frequently used to examine for hygiene indicators where enumeration of microbes in a unit/volume or mass is possible. An example of a three-class plan would be coagulase-positive Staphylococci in milk powder with five samples to be taken (n), two samples (c) allowed to fall between 10 cfu/g (m) and 100 cfu/g (M). If these limits are not met when testing a food lot, it can be reprocessed, rejected or destroyed and/or further investigations made to determine appropriate actions to be taken. The results can also result in checking the efficiency of heat treatment and prevention of recontamination. What actions are to be taken with this kind of microbial criterion depends on its status (standard, guideline or specification) and the actions defined in the criterion. Since many microbiological criteria are currently under revision, a list of them is not presented in this chapter. However, several reports and books have listed microbiological criteria for different foodstuffs (e.g. EC, 1998, ICMSF, 2002, FNB, 2003) and, for example, the European Commission is planning to have established a new set of microbiological criteria in 2006. The new code of Codex (2004) on microbiological risk management will most probably have a great influence on the development of criteria in future. In practice, the interpretation of microbiological results after testing is often made just by comparison with the microbiological criteria. However, it is important to keep in mind that confidence in a test result depends on many factors, e.g. lots selected for sampling, number of samples/units tested, homogeneity of the microbe distribution in the lot, randomization of sampling, time/temperature history of the samples at the time of analysis in the laboratory, true prevalence of microbe in the lot, sensitivity and specificity of the testing method and method validation and laboratory accreditation. Ensuring product safety by end product testing has a number of inherent weaknesses, not least the statistical problems associated with selecting samples for analysis. In fact, no sampling plan can assure the absence of a pathogen from a lot. These factors are often neglected in decision-making, and it may be forgotten that, e.g. one sample analysed with a method with poor sensitivity can lead to a false sense of product security. When current and planned microbiological criteria are studied, it can be seen that there are several factors which influence the setting of a criterion: 1. New trends and prerequisites for food control; 2. Different aims for microbiological testing; 3. Reality factors; and 4. The actual content of a criterion (Fig. 10.2). A final microbiological criterion is always a compromise of all these factors, e.g. it may be set without a clear connection to FSO or without formal risk assessment procedure. Microbiological criteria should be based on scientific knowledge and take into account the practical, economical, etc. aspects. Therefore, the first decision to be made before setting a criterion is its aim. If it will be applied to international trade as a mandatory criterion, the need for solid and transparent scientific background information is much higher compared to the setting of a specification between two companies. The traditional use of microbiological criteria to assess the safety of a specific lot or consignment is increasingly changing its focus to verifying the effectiveness of all or part of a food safety control system. In this context, microbiological criteria should be used only when they will have an impact on public health. In principle, they should, therefore, be one of the means to achieve the Appropriate Level of Protection (ALOP), which is, by definition, the level of protection deemed appropriate by the (WTO) member country establishing a sanitary or phytosanitary measure to protect human, animal or plant life or health within its territory (WTO, 1995).
10.1 Food Hygiene at Retail–Consumer Level
Food Safety at the Retail Level
Food legislation
The retailer – shops and supermarkets
Product shelf life
Date-marking of foods
Display of foods for retail
Chilled and frozen foods
Raw and cooked meats
Delicatessen foods
Catering establishments
Food Safety at the Consumer Level
Food-borne outbreaks in the home
Inadequate storage
Inadequate cooking
Cross-contamination
Pets in the kitchen
Further Reading
10.2 Microbiological Criteria for Foods
Introduction
Microbiological Criteria
Interpretation of test results
Setting microbiological criteria
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Food Hygiene and Safety at the Retail–Consumer Phase
