Coming eye-to-eye with rats in a shop's crisps aisle and seeing the aftermath of the illegal slaughter of more than 100 chickens is all in a day's work for Calderdale Council's environmental health team.

"You need to have a strong stomach in this job," says senior environmental health officer Mark Coleman.

"But you need to think that what you're doing is protecting people's health.

"We have no problems with businesses who are making a profit from food that is safe but if people are trying to make money through unsafe food then we need to stop them."

There are around 2,400 places serving food in Calderdale, and the officers have to inspect every one.

Peter Broadbent, environmental protection manager, said: "We are a small team but it's a busy team, our officers are out every day carrying out inspections."

Each is given a star rating – five being the best and zero the worst.

The food police visit the places getting the worst ratings the most often, carrying out inspections at least every six months. Those getting two or three stars are checked every 12 months, and four or five star premises are inspected every 18 months.

The environmental health team says they are keen to offer advice, especially to those getting the worst ratings, so they can improve their scores.

They will help with suggestions on improvements that can be made, support in keeping up to date with paperwork and information about food standards law.

They say they are always happy to answer questions.

But the best way for them to carry out their checks is if they make unannounced visits.

Mr Coleman says: "That way we see what the customers are exposed to.

"The number of times I've heard people worried because they've seen us at a premises but don't understand that we're just inspecting. It's just a health check."

The team receive more than 100 food-related complaints to investigate every year and nearly 200 requests for food safety advice.

They have the power to shut places down if they are deemed an imminent risk to public health.

Their investigations have led to several high-profile prosecutions, including Tesco, which was fined over £35,000 in March for selling ready meals and yoghurts up to 28 days past their sell-by date at its Brighouse store.

The work of the food police also involves investigating complaints of food poisoning and tackling bugs such as salmonella and e.Coli.

But they say this can be difficult if people do not go to their doctors.

"It's important people report their sickness so that we can stop premises who are risking people's health," says Mr Coleman.

Their inspections cover a wide range of issues, from asking questions about food-hygiene qualifications and business practice, to storage and hand-washing facilities checking for dirt, signs of rats, mice or any other pests.

The team say they receive a mixed response from Calderdale's food traders when they turn up to do their checks.

Among those pleased to see them is Sara-Jo Cooper from The Works at Hollins Mill Lane, Sowerby Bridge, which has been awarded the sought-after five star rating.

She said it is important members of the public have the opportunity to check on an eaterie's food hygiene score before they go out to eat.

She added: "If you have a business that serves food and want to get it right then you will take up every offer of help that is going."

Food Safety Week runs until Sunday.